?DVANCED EllGIAE STUDY FOR N79- VEHICLES Final · PDF file(NASA-CR-159491) ?DVANCED EllGIAE...

(NASA-CR-159491) ? D V A N C E D El lGIAE STUDY FOR N79- 19074 n1XED-MODE ORBIT-TRANSFER VEHICLES F i n a l Report (Aero j e t Liquid Rocket Co.) 228 p RC A I I / ~ P A Q I CSCL 2 18 Dnclas

63/20 16369

NASA CR-159491

ADVANCED ENG l NE STUDY FOR

MIXED-MODE ORB IT-TRANSFER VEHI CLES

by J. A. M e l l i s h

AEROJET L I Q U I D ROCKET COMPANY

p r e p a r e d fo r

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

NASA L e w i s R e s e a r c h C e n t e r

C o n t r a c t NAS 3-21 0 4 9

https://ntrs.nasa.gov/search.jsp?R=19790010903 2018-04-17T08:23:31+00:00Z

The work described herein was performed a t the Aerojet L i qu id Rocket Company under NASA Contract NAS 3-21 049 w i t h M r . Dean i). Scheer, NASA- Lewis Research Center, as Pro ject Manager. The ALRC Program Manager was Mr. Lar ry B. Bassham and the Pro ject Engineer was M r . Joseph A. Me1 1 ish.

The technical per iod of performance f o r t h i s study was from 22 September 1977 t o 15 September 1978.

The author wishes t o acknowledge the e f f o r t s o f the fo l low ing ALRC engineering personnel who contr ibuted s i g n i f i c a n t l y t o the study e f f o r t and t h i s report :

K. L. Christensen R. D. Entz J. W. Hidahl J. E. J e l l i s o n J. W. Salmon

I also wish t o thank M r . Rudi Beichel , ALRC Senior Sc ien t i s t , f o r h i s comments and assistance throughout the study e f f o r t .

TABLE OF CONTENTS

Section

I. Sumnary

A. Study Object ives and Scope

B. Results and Conclusions

11. In t roduct ion

A. Background

B. OTV Engine Requirements

C. Approach

111. Task I - Propel lant Propert ies and Performance

A. Objectives and Guidel ines

B . Propel 1 an t Property Data

C. Thrust Chamber Combustion Gas Propert ies and Theoretical Performance Data

D. Preburner Combustion Gas Propert ies and Performance Data

I V . Task I 1 - Cooling Evaluation

A. Objectives and Guidelines

B. Dual -Expander Engine Concept D e f i n i t i o n

C. Thrust Chamber Assembly (TCA) Geometry De f i n i t i ons

D. S t ruc tu ra l Analysis

E. Thermal Analysis

U. Task III - Base1 i n e Engine Cycle, Weight and Envelope Analysis

A. Objectives and Guidel irles

B. Engine System Evaluations

V I . Task I V - Engine Performance, Weight and Envelope Parametri cs

A. Object ives and Gui del ines

B. Parametric Data

V I I. Conclusions and Recommendations

A. Concl usions

Page

B . Recomrnenda t i ons

References

?RECED\NG P A M BLANK NOT FkM@

Table No.

I

I I

I11

I V

'J

V I

V I I

V I I I

I X

X

X I

X I I

X I I I

X I v X V

XV I

X V I I

X V I I I

X I X

X X

XX I

X X I I

X X I I I

X X I V

xxv

X X V I

X X V I I

LIST OF TABLES -

Base1 in€ Tri propel lant Engine Data Summary 10 Baseline Dual-Expander Engine Data Sumnary Base1 i ne Plug Cluster Engine Data Summary

Mixed-Mode OTV Engine Requirements

Case1 i ne Tri propel lant Engi ne Guidel i nes Base1 i ne Dual -Expander Engine Gui del i nes Base1 ine Plug Cluster Engine Guidel ines

Properties o f Candidate Propel lants

L02/RP-1 /H2 Tri propel lant TCA Gas Properti?:

L02/RP-1 Preburner ODE Gas Properties

L02/LH2 Preburner ODE Gas Properties

Coolant Evaluation Study Criteria

Thrust Chamber Geometry Definition Summary 58

Thermal Analysis Nomenclature 7 5 Tri propel 1 ant Engine Tube Bundle Pressure Drops

Tripropel lant Engine Cool ing Summary Plug Cluster Engine Cool i n g Summary

Dua 1 -Expander Engine Cool i ng Summary

Prel irninary Tri propel lant Engine Pump Analysis

Tripropellant Engine Operating Specifications, Mode 1

Tri propellant Engine Pressure Schedule, Mode 1

Tri propel lant Engine Operating Specifications, Mode 2

Tripropel lant Engine Pressure Schedule, Mode 2 1 20

Base1 ine Dual-Expander Engine Operating Specifications, Mode 1

Base1 ine Dual -Expander Engine Operating Specifications, 136 Mode 2 Baseline Dual-Expander Engine Pressure Schedule 137 Plug Cluster 02/RP-1 Gas Generator Cycle Pressure 143 Schedule

X X V I I I Pl ug Cluster 02/H2 Expander Cycl e Pressure Schedul e 145

LIST OF TABLES ( cbn td -

Table No.

- XXX

X X X I

X X X I I

X X X I I I

X X X I V

xxxv X X X V I

X X X V I I

X X X V I I I

X X X I X

Plug Cluster Engine Pre l imirldry Operating Spec i f ica t ions

LOX/RP-1 Pump Parameters For S ing le Shaft Turbine Drive

Baseline Tr ipropel l a n t Engine Data

T r i propel l a n t Engine Parametric Data, Mode 1 = 137 atms (2000 ps ia )

T r ip rope l lan t Engine Data, Mode 1 Thrust = 66723N (15,000 I b s ) , Thrust S p l i t = 0.8

Baseline Dual-Expander Engine Data

Dual -Expander Engine Parametric Data

Baseline Plug Cluster Engine Data

Plug Cluster Engine Parametric Data

Plug Cluster Engine Parametric Data, MR = 6.0, PC = 20.4 atm (300 ps ia)

Plug Cluster Engine Parametric Data, MR = 7.0, PC = 20.4 atrn (300 ps ia)

Plug Cluster Engine Parametric Data, MR = 6.0, PC = 34 atrn (500 ps ia)

Plug Cluster Engine Parametric Data, MR = 7.0, PC = 34 atm (500 ps ia )

Page

147

v i i i

LIST OF FIGURES

vw " Figure No. . ;'# ? -

Mode 1 T r i propel l a n t Engine Cycle Schematic

Mode 2 T r i propel l a n t Engine Cycle Schematic

Dual -Expander Engine, Mode 1 Schematic

Dual -Expander Engine, Mode 2 Schematic

Made 1 Plug Cluster Cycle Schematic

Mode 2 Plug Cluster Cycle Schematic

Advanced Engine Study For M i xed-Mode OTV Program Summary

Study Base1 ine Engines

Task I : Propel l a n t Propert ies and Performance

T r i propel 1 ant ODE Speci f ic Impul se

02/RP-I ODE Speci f ic Impulse

02/H2/RP-1 ODE (MRf = .2) ODE Sgec i f i c Impulse

02/H2/RP-1 uUE !MRf = .4) ODE Spec i f i c Impulse

02/H2/RP-1 ODE (MRf = .6) ODE Spec i f i c Impulse

O2/iI2/RP-1 ODE (MRf = .8) ODE Spec i f i c Impulse

02/Hp ODE Speci f ic Impul se

L02/RP-1 Fuel -Rich Preburner Performance

Tensi le Propert ies (Zirconium Copper)

Tensi le Stress-Strain

Creep-Rupture and Low Cycle Fatigue

Conduct iv i ty and Expansion

Prel iminary Mode 1 T r i propel l a n t Engine Schematic

Prel i m i nary Mode 2 T r i propel 1 ant Engine Schematic

Prel iminary Mode 1 Plug Cluster Engine Schematic w i t h HDF Module RP-1 Cooled

Prel iminary Mode 2 Plug Cluster Engine Schematic

Prel iminary Mode 1 Plug Cluster Engine Schematic w i t h HDF Module O2 Cooled

Prel iminary Dual-Expander Engine Schematic, Mode 1

Prel iminary Dual -Expander Engine Schema t i c , Mode 2

LIST OF FIGURES (cont.)

Figure No. Pqge

29 Dual -Expander Engine Nozzle Area Ratios 57

3 0 L02/RP-1/H2 Tr ipropel l a n t Engine Shear Coaxial 60 Element Performance

31 L02/RP-l/H? Tr ipropel l a n t Engine Shear Coaxial 61 Element Performance Versus Contraction Rat io and Chamber Pressure

3 2 Chamber Pressure Drop Due t o Combustion 62

3 3 Dual -Expander Combustion Chamber Geometry 65

34 Dual -Expander Ilozzl e Geometry 66

35 Copper Channel S t ra i n Concentration Factor 6 8

3 6 Allowable Temperature D i f f e r e n t i a l s f o r MMOTV 70 Regen Chambers

3 7 Allowable Channel Aspect Ratios f o r MMOTV 71 Regen Chambers

3 8 Gas-Side Heat Transfer Corre la t ion Coe f f i c ien t 74

3 9 Schematic o f Modif ied Wall = 5 Model 76

40 Channel Design Opt imizat ion Study a t Throat f o r 78 Hydrogen Cool i ng

41 Tr ipropel l a n t Engine Cool i n g Schematic 8 1

42 OTV Tr ipropel l a n t Radiation Cooled Nozzle Attach 82 Area Ratio

4 3 OTV T r i propel 1 ant Chamber Pressure Drop 86

44 OTV T r i propel 1 ant Chamber Pressure Drop I n c l udi ng 87 Tube Bundle

45 Plug Cluster Engine Cooling Schematic 89

4 6 OTV Plug Cluster LOX/LH2 Module Pressure Drop 9 3

47 Plug Cluster LOX/RP-1 Module Coolant Jacket AP 9 6

4 8 Plug Cluster LOX/RP-1 Module Cool ant Bul k Temperature 97

4 9 Dual -Expander Engine Cool i ng Schematic 9 8

50 Dual -Expander Engine Cool ant Pressure Drop 1 02

51 Mode 1 Tr ipropel l a n t Engine Schematic 105

5 2 Code 2 T r i propel 1 ant Engine Schema t i c

53 Head Coef f i c ien t vs Spec i f i c Speed

LIST OF FIGURES ( c o d

Figure No,

54

5 5

56

Inf luence o f Pump Size Upon Ef f ic iency

Pump E f f i c i ency vs Impel ler T i p Diameter

T r i propel 1 ant Engine Pump Discharge Pressure Requi rements

L f f e c t o f Thrust Spl i t Upon Hydrogen Pump Discharge Pressure Requirements

E f f ec t o f Thrust S p l i t Upon Oxygen Pump Discharge Pressure Requirements

RP-1 Pump Discharge Pressure Requirements for A1 1 Thrust Spl i t s

Mode 1 Dual -Expander Engine Schematic

Mode 2 Dual -Expander Engi ne Schematic

Pump Discharge Pressure Requirements f o r Dual-Expander Engine LOXIRP-1 System

Pump Discharge Pressure Requirements for Dual-Expander Engine LOX/LH2 System

E f f ec t o f Thrust S p l i t Upon Hydrogen Pump Discharge Pressure, Dual -Expander Engine

E f f ec t c f Thrust S p l i t Upon LOX/LH2 Oxygen Pump Discharge Pressure, Dual -Expander Engine

Mode 1 Plug Cluster Engine Schematic

Mode 2 Plug Cluster Engine Schematic

E f f ec t of Nozzle Area Rat io on Tr ip rope l lan t Engine Mode 1 Del ivered Performance

E f f ec t o f Nozzle Area Rat io on Tr ip rope l lan t Engine Mode 2 Del ivered Performance

E f f ec t o f Thrust on Tr ipropel l a n t Engine Mode 1 Del i vered Performance

E f f ec t o f Thrust on T r ip rope l lan t Engine Mode 2 Del i vered Performance

E f f ec t o f Area Rat io on Tr ip rope l lan t Engine Weight

E f f ec t o f Thrust on T r ip rope l lan t Engine Weight

E f f ec t o f ~ o z z l b ~ r e a Rat io on T r i propel lant Engine Envelope

L I S T OF FIGURES (cont.1

Figure No,

75

7 6

E f f e c t o f Thrust on Tr ipropel l z n t Engine Envelope

Dual -Expander Engine Mode 1 LOX/RP-1 Chamber Pressure

E f f e c t of Mode 1 Overal l Area Rat io on Dual -Expander Engine Mode 1 Del i vered Performance

E f f e c t o f Mode 2 Nozzle Area Rat io on Dual -Expander Engine Mode 2 Del ivered Performance

Dual-Expander Engine Mode 2 Nozzle Area Rat io

E f fec t o f Thrust on Dual-Expander Engine Mode 1 Uel i vered Performance

E f f e c t o f Thrust on Dual-Expander Engine Mode 2 Del i vered Performance

E f f ec t o f Mode 1 Overal l Nozzle Area Rat io on Dual- Expander Engine Weight

E f f ec t o f Thrust on Dual-Expander Engine Weight

E f f ec t o f Mode 1 Overal l Area Ratio on Dual-Expander Engine Envelope

E f f ec t o f Thrust on Dual -Expander Engine Envelope

E f f ec t o f Mode 1 Overal l Area Ratio on Plug Cluster Engine Mode 1 Del i vered Performance

E f f ec t o f Mode 1 Overal l Area Ratio on Plug Cluster Engine Mode 2 Del ivered Performance

Plug Cluster Module Area Rat io Requirements

E f f ec t o f Thrust on Plug Cluster Engine Mode 1 Del i vered Performance

E f f ec t o f Thrust on Plug Cluster Engine Mode 2 Del i vered Performance

E f f ec t o f Mode 1 Overal l Area Rat io on Plug Cluster Engine Weight

E f f ec t o f Thrust on Plug Cluster Engine Weight

E f f ec t of Mode 1 Overal l Area Rat io on Plug Cluster Engine Envet ope

E f fec t o f Thrust on Plug Cluster Engine Envelope

SECTION I

A. STUDY OBJECTIVES AND SCOPE

The major cb ject ives o f t h i s study program were t o provide design charac- t e r i s t i c s , parametric data and i d e n t i f y technology requirements f o r advanced engines t o be used on mixed-mode o rb i t - t r ans fe r vehic les (OTV).

Three basel i ne engine concepts ( tri propel 1 ant, 1 ug c luster , and dual - expander) were studied. Oxygen (02). kerosene (RP-17 and hydrogen (Hz) were evaluated as the propel lants f o r these engines. A basel ine Mode 1 t h rus t l eve l o f 88,964N (20,000 i b s ) and a t h rus t s p l i t o f 0.5 were preselected. (Thrust s p l i t i s defined as the r a t i o of the OzIRP-1 t h rus t t o the t o t a l engine thrust . ) This establ ished the base po in t f o r parametric evaluations.

To accomplish the study program object ives, the e f f o r t was d iv ided i n t o four technical tasks p lus a repor t ing task. I n Task I, the proper t ies and/or theore t i ca l performance o f the propel lants and propel lant combinations were determined over a parametric range. Task I 1 involved the evaluat ion o f th rus t chamber coo l ing methods f o r each of the concepts t o determine the maximum a t ta inab le chamber pressures w i t h i n the const ra in ts o f low cyc le thermal fat igue and propel lant propert ies. Upon completion of Task 11, cool ing methods were selected and the operat ing parameters f o r each o f the baseline engines were updated f o r use i n the remaining e f f o r t . I n Task I i I, cycle power 1 im i t s were established, po in t design chamber pressures were selected, and del i vered performance, weight and envelope dimensions were determined fo r each o f the base1 i n e engines. Using the Task I 1 1 resu l t s as a base, parametric analyses were then conducted over ranges o f t h rus t leve l , t h rus t s p l i t and Mode 1 area r a t i o i n Task I V t o provide the engine data and descr ip t ions necessary f o r mixed-3'1ode o rb i t - t r ans fe r - veh ic le studies.

8. RESULTS AND CONCLUSIONS

Simp1 i f i e d engine cyc le schematics o f the concepts selected as base1 ines and f o r parametric analyses are shown on Figures 1 through 6.

The t r i p r o p e l l a n t engine uses a staged combustion engine cyc le and a conventional be1 1 nozzle, To conserve space i n the shu t t l e payload bay, an extendi b l e / re t rac tab l e nozzle extension i s used. Thwe preburners a re used t o d r i v e the turbines. Oxygenlhydrogen fue l - r i ch gas dr ives the hydrogen turbopump, oxygenlhydrogen ox i d i z e r - r i & gas d r i ves the oxygen turbopump and oxygen1RP-1 fuel - r i c h gas dr ives the RP-1, turbopump. The exhausts o f a1 1 turbines are burned i n the main t h r u s t chamber dur ing Mode '1 operation. Only the 021H2 propel lants are burned dur ing Mode 2 operation.

FRDM

Fl\rr(

BOO

ST

8005

2

CONT

ROL

VALV

E

CHEC

K VA

LVE

SHUT

OFF

VAL

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PB

PREB

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P T

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TC

THRU

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O

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lt D

LVSI

TY

FUEL

(R

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STIO

N P

RO

Nm

Fig

ure

1.

Mod

e 1

Tri

pro

pe

lla

nt

Eng

ine

Cyc

le S

chem

atic

rn

BOOST

pnf?

Fig

ure

2.

Mod

e 2

Tri

pro

pel

lan

t E

ngin

e C

ycle

Sch

emat

ic

P:

a W

f t U z w

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OST

PO

W

TC

THRU

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HAM

BER

Fig

ure

6.

Hod

e 2

Plug

Clu

ster

Cyc

le S

chem

atic

I, B, Results and Conclusions (cont.)

The dual-expander engine burns oxygen as the ox id izer and RP-1 and hydrogen as the fuels i n Mode 1. Some o f the oxygen and a l l o f the RP-1 are delivered t o a central thrust chamber i n jec to r as i iquids. These propel lants are combusted and pa r t i a l 1 y expanded i n a conventional be1 1 nozzle. The r e s t o f the oxygen and the hydrogen are combusted i n preburners. An ox id izer- r ich preburner i s used t o provide the oxygen turbopump dr ive gases and a fuel-.r ich preburner i s used t o provide the RP-1 and hydrogen turbopump dr ive gases. The turbine exhaust gases are delivered to an annular combus- t i o n chamber. Expansicn of the O2/H2 combustion products occurs i n a forced def lect ion nozzle extension along w i th the complete expansion of the 021RP-1 center core combustion gases. During Mode 2 operation, the center th rus t chamber i s inac t ive and only the 02/H2 combustion gases are expanded i n the forced def lect ion nozzle. This substant ia l ly increases the Mode 2 area ra t io .

The plug c lus ter engine uses 021Hp and 02/RP-1 th rus t chamber modules clustered around a central plug of zero isentropic length w i th the module ex i t s touching . The oxygenlhydrogen sys tem employs an expander d r ive cycl e and the oxygen/RP-1 turbopumps are dr iven by fue l - r i ch oxygen/RP-1 gas- generator. Some o f the heated hydrogen i s used as base-bleed to improve the base th rus t contr ibut ion i n both Mode 1 and Mode 2. The 02/RP-1 fuel - r i c h turbine exhaust products are expanded through a 5:l nozzle. A l l of the nlodules f i r e i n Mode 1 operation while only the 02/H2 modules operate during Mode 2.

Hydrogen was selected as the coolant f o r the t r i p rope l l an t and dual - expander engines and the LOXILHp module of the plug c luster . Hydrogen cooled t r ip rope l lan t engines are pract ica l for the en t i re chamber pressure range o f 34 to 136 atm (500 to 2000 psia) and thrust s p l i t range o f 0.4 t o 0.8 investigated. Dual-expander engines are cooling l im i ted and the niaximum operating chamber pressures were defined as a funct ion o f th rus t s p l i t a t a baseline thrust o f 88,964N (20,000 l b ) as fol lows:

Mode 1 Chamber Mode 2 Chamber Thrust Pressure, Pressure, Spl i t atm (psia) atm (psia)

It may be possible t o ra ise these chamber pressure T'imi t s i f advanced technology chambers using a combination o f regenerative and transpi ra t i on cooling are considered. However, t h i s was beyond the study scope.

f'.

I, 6, Results and Conclusions (cont.)

Cooling of the LOXILH2 plug c l us te r engine module was p rac t i ca l over t t c e n t i r e chamber pressure range of 20.4 t o 68 atm (300 t o 1000 ps ia ) i - ivest igated. However, both oxygen and RP-1 cool ing o f the LOXIRP-1 ,. odule was found t o be impract ica l over the e n t i r e chamber pressure range. Oxygen cool ing o f the module i n the p lug c l u s t e r engine i s impract ica l because of phase changes a t low pressures and sh i f t s i n t ranspor t proper t ies near the c r i t i c a l temperature and pressure po in ts a t the higher pressures. HP-I cool ing u f these modules r e s u l t s i n excessive bu lk temperature Fises b(,cause o f wa l l temperature 1 im i t a t i ons imposed i n order t o p r o h i b i t cracking, g; m i n g and coking o f the RP-1 i n the coolant channels. The p lug c l u s t e r s udy proceeded assuming t h a t i f some o f the impur i t i es were removed from the Ri -1, the coolant bu lk temperature would no t be l i m i t i n g . A basel ine LOX/ RF- l chamber pressure o f 20.4 atm (300 ps ia ) was selected f o r the parametric evaluations.

With the coo l ing evaluat ion r esu l t s as a foundation, basel ine engine operat ing po in ts were selected. The basel ine engine weight, performance and envelope data for each o f the engine concepts were establ ished and are sumnarized on Tables I, I 1 and 111. Parametric studies were then conducted around these baselines. The parametric data i s presented i n Section V I f o r a t h rus t range o f 66.7 kN t o 400 kN (15,000 t o 90,000 l b ) , t h rus t s p l i t s from 0.4 t o 0.8, and ove ra l l Mode 1 area r a t i o s from 200:l t o a t l e a s t 600:l.

TABL

E I. -

BA

SE

LIN

E T

RIP

RO

PE

LLA

NT

ENG

INE

DATA

SU

MM

ARY

Th

rust

, N

(I

b)

ilod

e 1

88,9

64

(20,

300)

Th

rust

Sp

lit

0. 5

Cha

mbe

r P

ress

ure

, at

m

(ps

ia)

137

( 2,

001)

)

ilix

ture

Ra

tio

LOX

/RP

-1

LOX

/LH

2 O

ve

rall

No

zzle

Are

a R

ati

o

400 : 1

En

gin

e V

acuu

m

Del

i ve

red

Sp

ec

ific

Im

pu

lse

, se

c 41

3.6

En

gin

e D

ry !

Jeig

ht,

kg

(lb

)

No

zzle

Ex

it D

iam

ete

r,

rn (i

n.)

En

gin

e L

en

gth

, rn

(i

n.)

Ext

en

dib

le N

ozz

le R

etr

act

ed

E

xte

nd

ible

No

zzle

De

plo

yed

Mod

e 2

44,1

06

(9,9

15)

Th

rust

, N

(lb

)

Th

rust

Spl

i t

TABL

E 11

. -

BA

SE

LIN

E D

UAL-

EXPA

NDER

EN

GIN

E DA

TA

SUM

t4ARY

Cha

mbe

r O

ress

ure,

at

m

( ps

ia)

LOX

/RP

-1

Cha

mbe

r LO

XIL

H2

Cha

mbe

r

Mix

ture

Ra

tio

LOX/

RP -

1 LO

X/L

fi2

Ove

rall

Noz

zle

Are

a R

ati

o

LOX

/RP

-1

LOX

/LH

2 O

vera

ll

Eng

ine

Vac

uum

Del

i ve

red

Spe

ci f i c

Impu

lse,

se

c

Eng

ine

Dry

Wei

ght,

kg

(lb

)

No

zzle

Ex

it D

iam

eter

, m

(i

n.

)

Eng

ine

Leng

th,

m (i

n.)

Mod

e 1

Hod

e 2

88,9

64

(20,

000)

45

,497

(1

0,22

8)

0.5

TABL

E 11

1.

- BA

SE

LIN

E

PLUG

CL

USTE

R EN

GIN

E DA

TA

SUM

MAR

Y

Mod

e 1

88,9

64

(20,

000)

T

hru

st,

N (l

b)

Th

rust

Sp

lit

Num

ber

of

Mod

ules

Gap

B

etw

een

M~

du

i es/M

odul

e E

>.i t

Dia

. %

Ise

ntr

op

ic P

lug

Le

ng

th

Cha

mbe

r P

ress

ure

, at

m (

pz

i a)

LOX

/RP

-1

Mod

ules

LO

X/L

H2

Mod

ules

Mix

ture

Ra

tio

LOX

/RP

-1

Ove

ral

Are

a R

ati

o

LOX

/RP

-1

Mod

ules

LO

X/L

H2

Nod

ules

O

ve

rall

Geo

met

ric

Eng

ine

Vac

uum

Del

i ve

red

Sp

eci

fic

Impu

lse,

se

c

Eng

ine

Dry

Wei

ght,

kg

(I

b)

Eng

ine

Dia

met

er,

m

(in

.)

Eng

ine

Leng

th,

m

(in

.)

SECTION I 1

1141 RODUCT I ON

A. BACKGROUND

From the ea r l y t o mid-1 970ts, the NASA and DOD sponsored a number of studies which examined both i n t e r im and so-cal led f u l l c a p a b i l i t y vehic les f o r the i n t e r -o rb i t t rans fe r o f payloads. These studies, which considered sol id, storable, and cryogenic propel lants f o r main engine propul siqn, general ly cc,.i l uded t h a t a high area r a t i o , h igh pressure staged combustion cyc le engine i n a hydrogen-oxygen s t a y o f fered the highest payload capa- b i l i t y . Several veh ic le and propuls ion system concepts, however, d i d no t

1 . receive in-depth study as candidates i n t h i s ea r l y o r b i t - t rans fe r -veh ic le (OTV) e f f o r t . Not considered, f o r example, were the p lug c l u s t e r engine

. . and the more recent mixed-mode propuls ion concept. Work was i n i t i a t e d i n 1976 (Contract NAS 3-20109) t o provide p lug c l us te r engine data f o r use i n f u t u re hydrogen-oxygen OTV studies. H i t h regard t o mixed-mode propul s ion , studies of s ingle-stage-to-orbi t (SSTO) vehic les conducted by both indus t ry and NASA have shown t h a t mixed-mode p r o p ~ l s ion o f f e r s s i g n i f i c a n t bene f i t s i n veh ic le performance and s ize f o r advan~ed ear th - to -o rb i t t ranspor ta t ion systems. This suggests t h ~ t mixed-mode propul s ion might a lso be bene f i c ia l i n o r b i t - t r ans fe r vehicles.

Mixed-mode propuls ion consists of two separate modes (here in ca l l ed Mode 1 and Mode 2) of combustion i n the same propuls ive stage. This can be accomplished e i t h e r sequent ia l ly o r i n p a r a l l e l . During a Mode 1 p a r a l l e l burn, a high densi ty fuel , 1 i ke kerosene (RP-1) o r monomethyl hydrazi ne (MMH) , i s burned together w i t h oxygen and hydrogen. Only the h igh dens i ty fue l and oxygen a re burned dur ing Mode 1 of the ser ies concept. Oxygen (02) and hydrogen (HZ) are used i n the Mode 2 burn o f both concepts. I n Reference 1, Beichel and Sal keld compare an 02/MMH/H2 mixed-mode OTV w i t h a reference 02/H2 OTV which u t i l i z e d the RL10-IIB engine (standard RL10-3 w i t h add i t i on o f i d l e - mode capab i l i t y and an extendable nozzle t o an area r a t i o o f 205:l). Results showed t h a t the mixed-mode OTV was 60% shorter than the reference design a t no penal ty i n payload weight o r 43% shorter w i t h a geosynchronous payload increase o f 21%. The c i t e d improvements were accomplished by the app l i ca t jon o f the mixed-mode propuls ion p r i n c i p l e i n a high pressure oxygen-cool2d dual - fue l engine (Mode 1 area r a t i o = 130:1, Mode 2 area r a t i o = 400:1), use o f a 1 ightweight columbium r o l l i ng diaphragm nozzle extension, an 02/H2 mix ture r a t i o o f 7: 1, and storage o f the oxygen i n a to ro ida l tank o f spher ical seg- ments. The work o f Beichel and Salkeld was extended t o inc lude 02/RP-l/H2. These ALRC in-house e f f o r t s showed t h a t the OTV length could be reduced by 27% and the vehic le d ry weight reduced by 19% f o r essen t ia l l y no penal ty i n payload weight. A l l studies have shown t h a t the requirements f o r a small size, h igh performance OTV dr ives the m i xed-mode propul s i on t o high chamber pressures and large nozzle area ra t i os .

The purpose o f t h i s work was t o provide the data necessary f o r the study o f o r b i t - t ransfer -veh ic les u t i 1 i z i n g m i xed-mode propulsion. The e f f o r t

11, In t roduc t ion (cont. )

involved parametric analyses t o es tab l i sh engine data and descr ip t ions and the i d e n t i f i c a t i o n o f technology needs i n the propuls ion area.

B. OTV ENGINE REQUIREMEhTS

The requirements f o r the mixed-mode OTV engines used i n t h i s study are summarized on Table I V . I n addi t ion, the study was conducted assuming cur ren t l y achievable component performance 1 eve1 s and cur ren t l y ava i l able mater ia l s.

C. APPROACH

A summary of the study program e f f o r t i s shown on Figure 7. This f i g u r e shows the major past study e f f o r t s which provided basic data and inputs t o t h i s e f f o r t , the study tasks conducted and the outputs obtained. Much of the basic propel 1 ant data, proper t ies and theore t i ca l performance was ava i lab le from Contract NAS 3-19727 (Reference 2 ) t o support t h i s study. The resu l t s o f work performed f o r Contract NAS 3-20103 (Reference 3 ) were used t o es tab l i sh the plug c l us te r engine parameters such as, p lug i sen t rop ic length, module gap r a t i o and module nozzle expansion ra t i os .

The engine concepts described by Figure 8 were analyzed i n t h i s study. Those base1 i ne engine guide1 ines and parameters t ha t could be i d e n t i f i e d p r i o r t o the i n i t i a t i o n o f a l l de ta i led analyses are shown on Tables V, V I and V I I . A1 1 i tems marked TBI) ( t o be determined) were establ ished dur ing the study by conducting the tasks which fo l low.

" Task I - Propel lant Propert ies and Performance

This task generated fundamental data necessary f o r the performance o f the remaining tasks.

This task establ ished the best coolant f o r each o f three basel ine engines and determined the maximum a t ta inab le chamber pressure on the basis o f coolant pressure drop o r propel l a n t property 1 i m i t s .

" Task I 11 - Bacel i ne Engine Cycle, Weight and Envelope Analysis

This task consisted o f engine cyc le power balance analysis, engine del ivered performance evaluations , engine and component weight estimation, and engine envelope analysis f o r three base1 ine engine concepts selected on the basis o f the Task I and I 1 r esu l t s .

" Task I V - Engine Performance, Weight and Envelope Parametrics

Engine de l ivered performance weight and envelope d :a were generated over parametric ranges o f thrust , t h r u s t - s p l i t and Mode 1 ared r a t i o f o r each of the selected engine concepts.

TABLE I V . - MIXED-MODE OTV ENGINE REQUIREMENTS

Propel lants :

Oxidizer Mode 1 Fuel

Mode 2 Fuel

Propel lant I r r l e t Temperature:

Oxygen Boost Pump RP-1 Boost Pump

Hydrogen Boost Pump

NPSH a t Boost Pump I n l e t ( f u l l t h rus t ) :

Oxygen RP-1

Oxygen RP- 1 Hydrogen

0.61 m (2 f t ) 13.7 m (45 f t )

Hydrogen 4.57 m (15 ft)

Service L i f e Between 0,~erhaul s :

Service Free L i f e :

300 thermal cycles o r 10 hours accumulated run t ime

60 thermal cycles o r 2 hours accumulated run t ime

STUD

Y IN

PUTS

LONT

RACT

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3-1

9727

, AD

VANC

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PRES

SUR

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CONT

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TR

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(R

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, EN

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PAC

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i

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ER

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WEI

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AND

ENV

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Fig

ure

7.

Ad

van

ced

En

gin

e S

Tud

y fo

r M

ixed

-Mod

e O

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ram

Sun

mar

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TABLE V. - BASELINE TRIPROPELLANT ENGINE GUIDELINES

MODE 1 PROPELLANTS : O X I D I Z E R

FUEL

MIXTURE RATIO (O/F) 3.1 7 . 0

CHAMBER PRESSURE TBD

VACUUM THRUST, N ( I b f ) I 88,964 ( 2 0 , 0 0 0 ) I THRUST S P L I T (02/RP- 1 THRUST)

TAL THRUST

VACUUM IMPULSE, SEC . I TBD I DRIVE CYCLE

NOZZLE TYPE I 9 0 % B E L L I NOZZLE EXPANSION RAT!O I 4 0 0 : 1

TBD

TBD

TB D

STG. Cr)llB.

9 0 % BELL

40C : 1

TABLE V I . - BASELINE DUAL-EXPANDER ENGINE GUIDELINES

PR3PELLANTS : OXIDIZER

FUEL

MIXTURE RA"0 (O/F) I CHAMBER PRESSURE I VACUUM THRUST, N (I b f )

THRUST SPL IT (02/RP- 1 THRUST)

TOTAL THRUST

VACUUM IMPULSE, SEC I DRIVE CYCLE

NOZZLE TYPE

NOZZLE EXPANSION RATIO I

MODE 1

O2 O2 RP- 1

3.1

TBD TBD I

BELL Expansion- D e f l e c t i o n

MODE 2

O2

2 7 . 0

Expansion- D e f l e c t i o n TB D

TABLE V I I . - BASELINE PLUG CLUSTER ENGINE GUIDELINES

PROPELLANTS : OXIDLZER

FUEL

MIXTURE RATIO (O/F)

CHAMBER PRESSURE

VACUUM THRUST, 13 ( I b f )

THRUST SPLIT (02/RP- 1 THRUST)

TOTAL THRUST

VACUUM IMPULSE, SEC.

DRIVE CYCLE

NUMBER OF MODULES

MODULE NOZZLE TYPE

MODULE NOZZLE EXPANSION RATIO

MODULE GAP RATIO (GAP BETWEEN MODULES/MODULE EXIT DIA)

CLUSTER EXPANSION RATIO

PLUG ISENTROPIC LENGTH, %

MODE 1 :: I TBD TB D

i . 5

TBD

Gas Gen. Expander

5 5

90% BELL 90% BELL 1 TBO TED

I TBD

MODE 2

O2

7.0

TBD

TBD

Expander

5

90% BELL

TB D

1

TBD

TBD

SECTION 111

TASK I - PROPELLAtlT PROPERTIES AND PERFORMANCE

A. OBJECTIVES AND GUIDELINES

The ob ject ives o f t h i s task were t o provide propel lant and combustion gas property data, and theore t i ca l performance f o r the propel lants and propel l a n t combinations considered i n t h i s study. To accompl i s h these cbject ives, ! i te ra tu re surveys and analyses were conducted. Much o f the propel lant property data i s r ead i l y ava i lab le i n the 1 i t e r a t u r e and the best references are c i t e d herein.

The l o g i c diagram and var iab les considered i n conducting t h i s task a re shown on Figure 9. As noted by the f igu re , much o f the basic propel lant property data was already ava i lab le from Contract NAS 3-19727 (Ref. 2). I n addi t ion, combustion product and theore t i ca l performance data ava i l able from Contracts NAS 3-19727 and NAS 3-20109 (Ref. 3 ) were extended t o meet the study requirements.

The thermodynamic and t ranspor t property data f o r the combustion products were obtained from the One-Dimensional Equi 1 i b r i urn Computer Program w i t h Transport Propert ies (TMN 72), described i n Reference 4. This computer program was obtained from NASA/LeRC and includes ODE and frozen spec i f i c impulse and cha rac te r i s t i c v e l o c i t y data i n add i t i on t o the extensive com- bust ion gas t ranspor t property output.

Main chamber theoret ica l performance data was a1 sb generated using the prev ious ly referenced TRAN 72 computer program. The ODE performance por t ion of the program i s equivalent t o the JANNAF one-dimensional equ i l i- b r i um program.

B . PROPELLANT PROPERTY DATA

The physical and thermal property data f o r oxygen, RP-1, and hydrogen, were assembled for Contract NAS 3-19727 (Ref. 2 ) . Propert ies o f these various propel lants and t h e i r data sources are:

" Oxygen - References 5,6,7,8 " Hydrogen - Reference 9 " RP-1 - References 10,11

The data i s sumar ized on Table V I I I .

I n add i t i on t o these data, Reference 2 presents data on the propel lant operational charac te r i s t i cs ( i .e., safety, avai labf 1 i ty , cost hand1 ing, chemical s t a b i l i t y , mater ia l compat ib i l i t y , thema1 s t a b i l i t y , and corrosive- ness).

N

I NP

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PC

OPE

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ACTE

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029

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1

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THER

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MIC

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ALL

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FROM

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7 IN

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& 20

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(2)

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DATA

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FROM

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400

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(300

TO

200

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= 2

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TO

13

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= 1 T

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3000

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2000

PS

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1.

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1 (D

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O/F

=

7.0

(02/

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2.

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20

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TO

136

atm

(3

00

TO

20

00 P

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)

O/F

=

3.1

(02/

RP-

1)

O/F

=

7.0

(02

/~2

) 14)

2.

BIPR

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(BIP

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= 2

0.4

TO

306

atm

(3

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TO

4500

PS

IA)

(2)

O/F

'S

= TB

D

= 55

6 TO

13

67°K

T

c (1

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TO

24

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)

3. TR

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= TB

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= -2

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. -6

. -8

r5

(TO

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FUEL

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PER

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ANCE

--

--

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) 20

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4 a

tm

(300

T

500)

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DAT

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09

TASK

I1

L

111

Fig

ure

9.

Task

I:

P

rop

ella

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Pro

per

ties

and

Per

form

ance

TABLE VI I I. - PROPERTIES OF CANDIDATE PROPELLANTS

- Fornula -- -. -. -. b l e c u l a r Yeight 31.9988 2.01594

f .. -- .. - 173.5151

I Free;g Point. OK 224.8 I (-361.818) (-434.767) I I -5s) I

Ba i l i ng Point, 'K (OF)

C r l t i c a l Temperature. OK

('F) ------- Cr l t i c a l Pressure. MNlm2 5.063 2.344

(ps is) (731.4) --.- (340)

C r i t i c a l Density, kg/m3 436.1 31.43 - - j l b l f t 3 ) (27.23) (1.962) - -

Vapor Pressure a t 298.15"K. k~/rn' 1.8 ( a t 77'F. ps ia j

1

I Density. l l q u i d a t 298.15°K. kg/m3 1140.8" (a t 77*F. I b l f t l ) (49.94) ~ - 1 - (at 77OF. Btu/lb-OF) 7~1

V i ~ c o s i t y . l i q u i d I

a t 298.15°u. d / m .ima 1 nil^ 1 . I 3 I (at 77'F. l bd f t - se : ) ( 1 . 3 1 6 1 0 - (.~8:x10-5) i1.04~10-3)

Them1 Conductivity. l i q . a t 298.15'K. U/m-OK ( a t 77"F, Btu/ft-sec-OF)

Heat o f F o m t i o n , l ~ q u l d a t 298.1:*1. k c a l / m l -3.093" -2.134' (a t 77'C. B t u l l b ) (-174.0) (-1905) ( -796)

a At Nfi? b kcnl lg CH2 u n f t

111, Task I - Propel lant Propert ies and Performance (cont.)

C. THRUST CHAMBER COMBUSTION GAS PROPERTIES AND THEORETICAL PERFORMANCE DATA

This subtask consisted of the parametric evaluat ion o f one-dimensional equi 1 ibr ium (ODE) spec i f i c impulse, gas stagnation temperature, character- i s t i c exhaust ve loc i ty , molecular weight, thermal cx tduc t i v i t y , dynamic v iscos i ty , spec i f ic heat, spec i f ic heat r a t i o ( v ) , and D i t tus-Boel t e r f ac to r f o r the LOz/RP-1/LH2 t r i - p rope l l an t combination. The parametric mix ture r a t i o range var ied from 3.1 :I (LOz/RP-1 on ly ) t o 7.0:l (L02/LH2 on ly) . Chamber pressure values included i n the study were 20.4, 34, 68, and 136 atm (300, 500, 1000 and 2000 ps ia) . ODE spec i f i c impulse was a1 so evaluated over an expansion area r a t i o range from 1 :1 t o 3000:l. The TRAN 72 computer program (Ref. 4) was used to ca lcu la te the ODE TCA performance and gas propert ies. Propel lant molecular formulas and heats o f formation used were presented i n Table VIII.

The data were calculated f o r hydrogen t o t o t a l fue l f l ow r a t i o s ( fue l f rac t ions ) of 0, 0.2, 0.4, 0.6, 0.8 and !.O and the fo l low ing ove ra l l ox id ize r t o t o t a l fue l mixture r a t i os :

Fuel Overal l Fraction, Mixture Ratio,

0.0 3.10 (LOXIRP-1 on ly )

1 .O 7.00 (LOX/LH2 only!

The ra t iona le f o r the se lect ion o f the ove ra l l mixture r a t i o po in ts f o r each o f the fue l f rac t ions i s described i n the fo l lowing paragraph.

The theoret ica l one-dimensional vacuum spec i f i c impulse was ca lcu la ted for the LOX/Ltt2/RP-1 t r i p r o p e l l a n t combination a t an area r a t i o of 400:l and a chamber pressure o f 68 atm (1000 ps ia) . This i s shown f o r the various fuel f ract ions on Figure 10. Both maximum IS and maximum bulk densi ty speci f ic impulse occur a t a mixture r a t i o 3.1 f o r LOX/RP-1 a t t h i s high area r a t i o . Hence, t h i s mixture r a t i o was selected f o r LOXIRP-1 operat ion. The contract Statement o f Work spec i f ied a mixture r a t i o o f 7.0 f o r the LOXILH2 Mode 2 operation. This se lec t ion i s based upon analyses such as

490

480

470

460

A50

440

U W

430 v,

C

U W can 420 >o cn

C(

41 0

900

390

380

370

k~~ = 0 ( L o x / I ? ~ - only)

Figure 10. T r i -Propel l a n t ODE Specif ic Impulse

I1 I, C, Thrust Chamber Combustion Gas Propert ies and Theoret ical Performance Data (cont.)

Beichel 's and Salkeld 's (Ref. 1) which conclude t h a t some penal ty i n 0Z/h2 engine performance i s warranted t o obta in a higher propel lant bu lk densi ty. Therefore, as higher percentages o f Hz are put i n t o the t r i p r o p e l l a n t system, i t i s des i rab le t o move s l i g h t l y o f f peak performance. This i s represented by the l i n e passing through the various f ue l f r a c t i o n performance curves. The equation f o r t h i s l i n e i s a func t ion o f the mixture r a t i o s f o r the LOXIRP-1 and LOX/LH2 systems as we1 1 as the fue l f rac t ion . For the selected mixture r a t i o s :

MRo = Overal l mix ture r a t i o

MRf = Fuel Fract ion

ODE spec i f i c impulse i s p l o t t e d versus area r a t i o f o r each f ue l frac- t i o n ca lcu la t ion po in t on Figures 11, 12, 13, 14, 15 and 16. The very high area r a t i o data was establ ished i n an attempt t o cover a l l possible po in ts tha t might r e s u l t f o r the various engine concepts over a wide t h rus t s p l i t range.

The TCA combustion gas property data i s shown on Table I X . The symbols used on t h i s tab le are:

PC = chamber pressure

MRo = ove ra l l mixture r a t i o

MRf = f ue l f rac t ion

C* = charac te r i s t i c exhaust ve l oc i t y

To = c~mbust ion temperature (gas stagnation temperature)

PIb, = molecular weight

CHAM

BER

PRES

SURE

, a t

m (P

SIA

)

38 0

10

1 00

1,00

0 10

,000

Are

a R

ati

o (

%/A

t)

Fig

ure

12.

02

/H2/

RP-1

OD

E (M

Rf

=

.2)

ODE

Sp

ec

ific

Imp

ulse

' ' I*:. '

1

CHAM

BER

PRES

SURE

at

m

(PS

IA)

136

( ~O

(N)

68

(1

000

) 34

(

500)

20

.4

( 30

0)

490

470

460

450

--

440

h'd-

='--

l L

#

' *

,?

,*

I

t #

t 1

I1

11

i a

7 90

7,03

0 IO,OOO

Are

a R

zti

a (

A,/P

,)

Fig

ure

16.

02

/H2

ODE

Sp

ec

ific

Im

pu

lse

mmmmmm mmmmmm m m m m m m m m a e e e ? - - - - C ------ .--.--c--- ------ :I . . . . . . . . . . . . . . . . . . . . . . . . - c 7-ccc- .---F--- .?--F-F

-3 i - o a ~ m m m o m h ~ h ~ a c u h - a a a ~ h ~ m ~ - h ~ m b N N Q W ~ ~ m w m m h m m m o a c o o

Y E T=ryqyT y y y q y : ? y y q ? Y y q y T T y

h a * - m m -3mr-W-N NNGCnWuY -.$aa.-m m b c v a o m OlnNOrna) - W W O r n h GZSJS2 m m m - m * ,,,wmm m,hh,to

mmmmmm mmmmmm mmmmmm o m m m m m

=Tm-wmm w h Q < U h - U L A U 3 h h J :

I . . . . .

- m N O 0-Qml.F. LI)V)NbOC.) mw-Wr. q q - y N e : 8 - w m m m . . . w w w w w d d d d d

mm%r-WN hN0113UC.I w CU LC, 0') 'a N LDWIDIDhh

I I I, C, Thrust Chamber Combus t i o n Gas Proc l r r t ies and Theoret ical Performance Data (cont.)

Kf = thermal conduct iv i ty

Ye = r a t i o o f spec i f i c heats, equ i l i b r ium

Yf = r a t i o o f spec i f i c heats, frozen

= dynamic v i s cos i t y

Cpe = spec i f i c heat a t constant pressure, equ i l i b r ium

C ~ f = zpec i f ic heat a t constant pressure, f rozen

Dbf = Di t tus-Bol e l t e r f ac to r

D. PR'EBURNER COMBUSTION GAS PROPERTIES AND PERFORMANCE DATA

This subtask consisted o f ca lcu la t ing the combustion gas proper t ies for f ue l - r i ch and ox i d i ze r - r i ch L02/RP-1 and L02/LH2 preburner operation. These data were developed over a chamber pressure range from 20.4 t o 408 atm (300 t o 6000 ps ia ) and mix ture r a t i o ranges corresponding t o gas temperatures between a t l eas t 700 t o 1367°K (1260 t o 2460°R).

The data presented i n t h i s repor t i s a compi lat ion of r esu l t s obtained during t h i s program and appl icab le data f o r pressures o f 136 t o 408 atm (2000 t o 6000 ps ia) developed dur ing d s im i l a r task on the Advanced High Pressure Engine Study, Contract NAS 3-19727 (Ref. .2). The LOz/RP-I preburner gas property data presented i n t h i s reference a t pressures o f 136, 272 and 408 atm (2000, 4000, 6000 ps ia ) was expanded t o the lower chamber pressures o f 20.4, 34, and 68 atm (300, 500, and 1000 ps ia ) used i n t h i s study. No propel lant pre-heating was allowed f o r s ince Hz was the baseline TCA coolar,t f o r t h i s study. The non-equil ibrium performance o f the f ue l - r i c h LO /RP-I perfomance was accounted f o r as described i n Ref. 2. Also, the LO2 f LH2 preburner gas property data presented i n the reference was ve r i f i ed as accurate f o r the 20.4 t o 68 atni (300 t o 1000 psia) pressure range. Therefore, t,he L02/LH2 data i s v a l i d f o r a l l pressures from 20.4 t o 408 atm (300 t o 6000 ps ia) .

Study preburner gas proper t ies were a lso ca lcu la ted w i t h the TRAY 72 computer program (Ref. 4) . L02/RP-1 preburner gas proper t ies are tabulated i n Table X. The symbols used on t h i s tab le were defined i n SectSon I1I.C. The stagnation temperature, cha rac te r i s t i c exhaust ve loc i t y , molecular weight cnd spec i f i c heat r a ~ i o data shown on t h i s tab le were adjusted from t h e i r ODE values for the L02/RP-1 f ue l - r i ch preburner data. The adjusted To and C* data along w i t h molecular weight and spec i f i c heat r a t i o are p l o t t ed i n Figure 17. This adjustment accounts f o r the emp i r i ca l l y observed non- equi l ib r ium performance o f fuel - r i c h hydrocarbonloxygen mixtures. E f f i c i ency factors were devtloped \lersus equivalence r a t i o , as described i n Ref. 2, and used t o p red ic t To and C* values a t the s ta ted chamber pressures.

L02/LH2 preburner data were a1 so ca lcu la ted a t chamber pressures of 20.4, 34 and 68 atm (300, 500, and 1000 ps ia ) . These data agreed w i t h

TABL

E X.

-

LOX/

RP-1

PR

EBUR

NER

ODE

GAS

PRO

PERT

IES

S.I

. UN

ITS

CPf

' Cal

/g-O

K

NOTE

S:

(1)

Ox

idiz

er-

ric

h

pro

per

ties

do

no

t ch

ange

as

a fu

nct

ion

of

cham

ber

pre

ssu

re f

rom

20

.4

to 4

08 a

tm.

TABL

E X

(con

t. )

ENG

LISH

UN

ITS

NOTE

S:

(1 )

Ox

ldlz

er

Ric

h P

rop

ert

ies

Do

Not

Cha

nge

as a

Fu

nct

ion

of

Cha

mbe

r P

ress

ure

fro

m

300-

6000

p

sla

PC = 34 atm (500 P S I A )

PC = 20.4 atm (300 P S I A )

M I X T U R E R A T I O , O/F

Figure 1 7 . L02/RP-1 Fuel-Rich Preburner Performance

. i i '. ; 1 . : : i ' , . 111, D, Preburner Combustion Gas Properties and Performance Data (cont.)

'- .$

, ! f

. z ! ! I ; previous data developed for the 136 to 408 atm (2000 to 6000 psia) pressure range. The LOz/LHz preburner data i s shown on Table X I . I t was concluded

1 . that the LO /LH2 preburner performance curves presented in Ref. 2 were

. i / . t 4 .

valid for t 2 e parametric pressure range of this study.

TABL

E X

I. - L

OX/

LH2

PREB

URNE

R OD

E GA

S PR

OPE

RTIE

S

S.I. UNITS

C*

To,

atm

-

O/F

m

/sec

O

K

---

3CO

% E

4

to

1.

CCOO

1.

5

300

to. '

70

6000

12

0 20

0

ENGLISH UNITS

SECTION I V

TASK I I - COOLING EVALUATION


The primary ob jec t i ve o f t h i s task was t o determine the r e l a t i v e capa- b i l i t y o f oxygen, RP-1, and hydrogen t o cool the t h rus t chamber and nozzle o f the t r i p r o p e l l ant, p lug c luster , and dual -expander OTV engine concepts. Secor~dary ub j2ct ives were t o : ( 1 ) establ i sh cool i ng methods and associated power cycles f o r the dual-expander engine concept, and (2 ) def ine the geometry o f the t h rus t chamber and nozzle f o r each o f the basel ine OTV engine concepts.

Parametric hydraul i c , heat t ransfer and low cyc le fa t igue analyses were conducted over the fo l low ing ranges o f chamber pressure and t h rus t s p l i t .

Chamber Pressure Thrust Engine Concept atm (ps ia) Spl i t

Tr ipropel l a n t 34 t o 136 (500 t o 2000) .4 t o .8

Plug Cluster 20.4 t o 68 (300 t o 1000) .5 Dual-Expander 34 t o 136 (500 t o 2000) .4 t o .8

The r e l a t i v e me r i t o f the various cool ants considered (Figure 8) were evaluated on the basis o f a t ta inab le chamber pressure, as r e f l ec ted i n the coolant pressure drop. This evaluat ion was conducted w i t h i n the const ra in ts o f the study c r i t e r i a l i s t e d i n Table XI1 and considerat ion o f the po ten t ia l problems and 1 im i t a t i ons such as coking o f RP-1 and i n s t a b i l i t i e s i n subcr i t i c a l oxygen heat exchangers.

The Task I 1 guidel ines provided by NASA/LeRC are sumnari zed on Table XI1 and Figures 18 through 21. Rectangular channel const ruct ion was spec i f i ed i n the high heat f l ux por t ion o f the chambers using a zirconium-copper a l loy . The channel dimension and wa l l thickness 1 i m i t s are presented on Table X I I . Figures 18 through 21 show the zirconium-copper proper t ies used i n t h i s study.

The cool ing methods and assoziated power cycles evaluated for the tripropel lant and plug c l us te r ccncepts are shown on Figures 22 through 26. These concepts were defined by the cont ract statement o f work. The dual- expander concept was defined dur ing the study and i s described i n the next section. As shown by the figures, the basel ine plug c l us te r concept i s regenerat ively cooled. The t r i p rope l l a n t engine i s regenerat ively cooled t o a nozzle area r a t i o corresponding t o the po in t where a r ad ia t i on cooled nozzle can be u t i l f z e d . This t r a n s i t i o n area r a t i o was establ ished dur ing the study.

TABLE X I I . - COIILANT EVALUATION STUDY CRITERIA

O Coolant I n l e t Temperature

O Coolant I n l e t Pressure

Staged Combustion Cycle: 2.25 times chamber press. Gas Generator Cycle : 1.8 times chamber press. Expander Cycle: 2.25 times chamber press.

O Service L i fe : 300 cycles times a safe ty f ac to r o f 4

O High heat f l ux por t inn o f chamber sha l l be o f nontubular co~ i s t r uc t i on w i t h the fo l low ing dimensional 1 i m i t s :

Minimum S l o t Width = 0.762 mn (.03 i ; ~ . ) Flaximum S l o t DepthIWidth = 4 t o 1 Minimum Web Thickness = 0.762 mn (.03 i n . ) Minimum Wall Thickness = 0.635 mn (.025 i n . )

O Mater ia l (nontubular po r t i on ) : Copper a1 l o y (Zirconium Copper) con- forniing t o proper t ies given i n Figures 18 through 21

O Maximum Coolant Veloci ;'I

i i q u i d : To Be Determined Gas : To Be Determined

O Possible Bene f i t o f Carbon D e p ~ s i t i o n on Hot Gas Wall sha l l be Neglected

O Coking L i m i t

RP-1 Coolant Side Wall Temperature = 58g°K (600°F)

Creep-Rupture

U) U)

2 G i i i i 9 w P .r V) r w k-

Figure 20. Creep-Rupture and Low Cycle Fatigue

700°K (800°F)

,.

Time to Rupture, h rs 1 - 100 1 1

5. -. c, C 0, U L aJ 0

" w m C (0 P:

e I.-- .F (0 L u V)

C

Q C, 0 c.

L

t- W a

0.1 -

4

Range: 2.Z°K to 8G6.7OK (-456°F t o llOO°F)

Low-Cycl e Fatigue

1 I

L ______t

1 00 1000 10,000 Cycles t o Failure

I r 1

I I

I I

I I I

33.1

25

5.4

477.8

700.

0 92

2.2

(-400)

(0)

( 400

) (8

00

) (1

200)

TE

MPER

ATUR

E O

K (OF)

Figu

re 2

1.

Cond

ucti

vity

and

Exp

aasi

on

FROM

PR

OM

FROM

BO

OST

.

BOO

ST

BOO

ST

P

XZ

XX

HYDROGEN

PB

PREB

URNE

R 7

Z OXYG

EN

P PU

MP

- HIG

H DENSITY

FUEL

(RP

-1)

T TU

RBIN

E COhfBUSTION PR

ODUC

TS

. . . TC

TH

RUST

CH

AMBE

R

TRIPROPELLANT

MOD

E 1

OZ!HDF/HZ

HYDR

OGEN

COO

LED

Fig

ure

22.

Prel

imin

ary

%de

1 T

ri p

rope

l lan

t E

ngin

e S

chem

atic

FROM

BO

OST

FROM

BO

OST

PUMP

I.

PUM

P

HYDI

IOGE

N .

. PB

PR

EBUR

NER

P PU

MP

m. OX

YGEN

T

TURB

INE

COM

BUST

1oN

TC

THRU

ST C

HAMB

ER

PIP

RO

PE

LM

T

MOD

E 2

02

'"~

HY

DROG

EN C

OCLE

D .

Fig

ure

23.

P

rel '

qin

ary

Mod

e 2

Tri

pro

pel

lan

t E

ngin

e S

chem

atic

FRO

n B

OO

ST

PUM

P

FRO

M

BOO

ST

PUM

P

GG

GAS

GENE

RATO

R GB

GE

AR

BOX

P PU

MP

T TU

RB

INE

TC

THRU

ST

CHAM

BER

L !

L-

L

,=-&

, CO

MBU

ST I O

N PR

OD

UC

TS

Fig

ure

25.

Pre

lim

inar

y M

ode

2 P

lug

Clu

ster

Eng

ine

Sch

emat

ic

FRO

U

830S

T

PUMP

FRO

M

BO

OST

P

OX

?

mom

BOO

ST

PW

P

HDF w

Hl G

H O

EN

SIT

Y

F'iS

L !f??-! )

- P='J

CO

Flbi

fST

f O?; PZC

DSCT

S cC

Fig

ure

26.

P

reli

min

ary

Mod

e 1

Plu

g C

lust

er ~

n~

in

e

Sch

emat

ic w

ith

HD

F M

odul

e O

2 C

oole

d

I V , T ~ s k I 1 - Cooling Evaluatfon (cont.)

0. DUAL-EXPANDER ENGINE CONCEPT DEFINITION

The dual -expander engine concept analyzed dur ing t h i s study was def ined and i s shown schematical ly on Figures 27 and 28.

The dual-expander engine burns oxygen as the ox i d i ze r and RP-1 and hydrogen as the fue ls i n the t r i p rope l l a n t Mode 1. Some o f the oxygen and a l l o f the RP-1 are pumped t o h igh presswe and de l ivered t o a cent ra l t h r u s t chamber i n j e c t o r as 1 iqu ids . These propel l an t s a re combusted and p a r t i a l l y expanded i n a conventional b e l l nozzle extension. The r e s t o f the oxygen and the hydrogen are combusted i n preburners. An ox i d i ze r - r i ch preburner i s used t o provide the oxygen turbopump d r i ve gases and a f u e l - r i c h preburner i s used t o provide the RP-1 and hydrogen turbopump d r i v e gases. The turb ine exhaust gases are de l ivered t o an annular combustion chamber. Expansion of the 0 /Hz combustion products occurs i n a forced def lec t ion f nozzle extension a ong w i t h the complete expansion of the 02/RP-1 center core combustion gases.

During Mode 2 operation, the center t h rus t chamber i s i nac t i ve and on ly the 0 /Hz combustion gases are expanded i n the forced def lec t ion 2 nozzle. T i s subs tan t ia l l y increases the Mode 2 area r a t i o .

The statement of work spec i f i ed a base1 ine t h rus t o f 88964N (20,000 l b ) a t h rus t s p l i t o f 0.5 and a Mode 1 nozzle area r a t i o o f 200:l f o r the dual -expander engine. I n addi t ion, the cool i ng evaluat ion was performed fo r a t h rus t chamber pressure range of 34 t o 136 atm (500 t o 2,000 ps ia ) and t h rus t s p l i t s from 0.4 t;o 0.8.

To es tab l i sh the dual-expander engine geometries, i t was necessary t o def ine the ind iv idua l system area r a t i o s and Mode 2 engine area r a t i o f o r the f i x e d basel ine Mode 1 area r a t i o o f 200:l. The fol lowing sketch and equations show the areas, area r a t i o s and in te r re la t ionsh ips .

I V , B, Dual -Expander Engine Concept D e f i n i t i o n (cont . )

where:

E = Mode 2 Area Rat io = A E / A ~ ~ 0

E~ = Mode 1 LOXIRP-1 Area Rat io = A ~ l / A t l

E2 = Mode 1 LOX/LH2 Area Rat io = A E ~ / A ~ ~

F = Mode 1 Area Rat io (LOXIRP-l/LH2) = A~l(At.1 + Atp)

= Throat Area LOX/RP-1 Nozzle

It' = Throat Area LOX/LH2 Nozzle A t 2 Equations ( 2 ) and (3) can be approximated by:

where :

FS = Thrust S p l i t

Pc2 = LOX/LH2 Chamber Pressure

Pc l = LOXIRP-1 Chamber Pressure

For a f i x e d Mode 1 engine area r a t i o , numerous valuer o f €1 and ~2 can be chosen t o s a t i s f y Equation (5 ) . However, the nozzle e x i t pressures a t ~1 and €2 must be equal and t h i s closes the so lu t ion prov id ing t h a t the r a t i o o f the LOXILH2 and LOX/RP-1 system pressures are known.

I V , B, Dual -Expander Engine Concept De f i n i t i on (cont. )

Prel iminary heat t rans fe r analysis ind icated t h a t i t i s des i rab le t o maintain a 0.5 r a t i o of the LOX/LH2 system chamber pressure t o LOXIRP-1 system chamber pressure. This i s based upon maintaining approximately equivalent th roa t heat f luxes i n the annular and b e l l nozzles. This was used throughout the r e s t o f the coolant evaluat ion study and more de ta i l ed thermal analyses (Section IV,E,5) ve r i f i ed t h i s assumption.

Based upon the foregoing analysis, nozzle area r a t i o s can be defined for a l l modes of operat ion as a func t ion of t h rus t s p l i t . Typical resul t ; are displayed on Figure 29 for an overa l l Mode 1 ( t r i p r o p e l l a n t operat ion) area r a t i o o f 200:l.

C . THRUST CHAMBER ASSEMBLY (TCA) GEOMETRY DEFINITIONS

Thrust chamber geometry analyses were conducted t o de f ine the chamber length and cont ract ion r a t i o f o r the t r i p rope l l an t , p lug c l u s t e r and dual- expander engines over the parametric design ranges. The r e s u l t s of these analyses are summarized on Table X I I I . A b r i e f descr ip t ion o f the geometry analysis conducted f o r each engine concept fol lows.

1 . T r i propel 1 ant Engine

The base1 i ne tri propel l a n t engine concept u t i 1 i zes a staged combustion cyc le comprised of para1 l e l O2IH2 (Hzr ich) , 02/H2 (Ozr ich) , and 02/RP-1 (RP-1 r i c h ) preburners and a gaslgas i n j ec ted primary t h r u s t chamber. I n Mode 1, a l l three preburners operate. The TCA i s hydrogen cooled, and the t o t a l preburner f low ra tes are i n l e t t o the i n j ec to r . I n Mode 2, the 0 /RP-1 (RP-1 r i c h ) preburner i s shutdown. TCA gas condi- t i ons were esta g l i shed t o provide inpu t condi t ions for a gas/gas mixing performance analysis which was used t o es tab l i sh chamber length requi rements t o meet an ERE (energy release e f f i c i e n c y ) goal o f 982.

I n j e c t o r energy release e f f i c i ency was evaluated as a funct ion o f chc~nber 1 ength ( L ' ) , chamber pressure (PC), chamber cont ract ion r a t i o ( r C ) , and i n j e c t o r pressure drop using a simp1 i f i e d gas/gas mixing model (Ref. 12). The analysis was i n i t i a t e d by se lec t ing an i n i t i a l design po in t and evaluat ing i n j e c t o r ERE as a funct ion o f chamber length f o r a shear coaxial i n j ec to r . The shear coaxial i n j e c t o r was selected on the basis of analysis and evalua- t ions conducted f o r the Advanced High Pressure Engine Study ;Reference 2). The chamber leng th study was conducted for a constant t h rus t per element (FIE) o f 703N (158 1 b f ! which r esu l t s i n 127 elements a t the basel ine 88964N (20,000 I b f ) t h rus t l e v e l . This element s i ze was selected on t.he basis of

Aerojet L iqu id Rocket Company (ALRC) Space Snu t t le A u x i l i a r y Propulsion System (APS) and M-1 Engine design experience.

I NOTES: ( 1 ) OVERALL TRIPROPELLANT MODE 1 AREA RATIO = 200

- ( 2 ) RATIO OF LOX/LH2 PC TO LOXIRP-1 PC = 0.5

0 l I 1 1 1 1 0.3 0.4 0.5 0.6 0.7 0;8

THRUST SPLIT

F igure 29. Dual -Expander Engi ne Nozzle Area Rat ios

TABL

E X

III.

-

THR

UST

CHA

MBE

R G

EOM

ETRY

D

EF

INIT

ION

SUH

MARY

Pro

pe

l la

nt

Cha

mbe

r E

ngin

e C

once

pt

Eng

ine

inje

ctio

n

Co

ntr

act

ion

L

' C

ycle

P

rop

ell

an

ts

- S

tate

R

ati

o -

cm

(in

che

s )

Tri

pro

pe

l la

nt

Stg.

C

mb.

O

z/R

P-l/

H2

Gas

-Gas

2.

0 5.

51

-+

15.2

4 2.

17

4-c +

6.0

O

Plu

g C

lust

er

02/!i

2 M

odul

e E

xpan

der

o2

IH?

L

iqu

id-G

as

3.3

6.35

J2

3.1/P

c +

9.91

2.

50 .?==

+

?-9

02/R

P-1

M

odul

e G

as-G

en.

02/P

?-1

Liq

uid

-Liq

uid

3

.3

6.68

J2

0.4/

Pc +

30.

48

2.63

flm

c

+ 12

.0

Dua

l E

xpan

der

02/R

P-I

C

ente

r C

ompo

site

02

/RP

-1

Liq

uid

-Liq

uid

3

.3

6.68

v'

20.4

/Pc

+ 30

.48

2.63

17-c

+ 1

2.0

Cha

mbe

r

0 /H

A

nn

ula

r S

tg.

Comb.

02/H

2 G

as-G

as

3.3

6.35

m

C

+ 9.

91

2.50

/

Im

p;

+ 3

.9

~ft

am

be

r

L'

= C

ham

ber

Le

ng

th =

C

yli

nd

ric

al

Le

ng

th +

C

on

ica

l S

ecti

on L

en

gth

PC =

Cha

mbe

r P

ress

ure,

at

m (

ps

ia)

I V , C, TCA Geometry De f i n i t i ons (cont,)

Figure 30 shows ERE versus chamber length and notes the i n i t i a l analysis design condi t ions. Three fue l i n j e c t i o n pressure drop values were evaluated because shear coaxial element performance i s sens i t i ve t o the r e l a t i v e fue l t o ox id ize r i n j e c t i o n ve loc i t y . Figure 30 ind icates a maximum chamber l e t ~ g t h requirement o f 17.8 t o 22.9 cm (7-9 inches) t o guarantee the 98% ERE goal. A length o f 20.3 cm (8 inches) was selected f o r the nominal design po in t .

A f t e r the se lec t ion o f a design chamber length o f 20.3 cm ( 8 inches), the inf luences of chamber cont ract ion r a t i o and chamber pressure on ERE were determined. Figure 31 presents these resu l t s . The top p l o t ind icates t ha t ERE increases as chamber cont ract ion r a t i o ( E ~ ) decreases. The bottom p l o t shows that, f o r a constant t h rus t per element, ERE increases as chamber pressure increases. The se lect ion o f the design chamber cont ract ion r a t i o was tempered w i t h the knowledge t h a t the Rayleigh l i n e combustion pressure loss increases w i t h decreasing con t rac t ion r a t i o , as shown on Figure 32. A design cont ract ion r a t i o value o f 2.0:l was selected t o minimize the combustion pressure loss and chamber weiqht and t o a t t a i n near maximum performance.

TCA th roa t area requi r m e n t s were eval ua ked f o r t h r u s t s p l i t s from 0.2 t o 0.8 and f o r a chamber pressure range from 34 t o 136 atm (500 t o 2000 ps ia) . Thrust s p l i t does not s i gn i f i can t l y in f luence the required chamber th roa t area, Using a radius equal t o one th roa t radius. RT, t o blend i n the chamber cy l i ndr ica l and convergent sections and the convergent sect ion t o the throat , the fo l lowing formula was developed t o account f o r chamber length va r ia t ions w i t h chamber pressure:

L ' = 3.18 RT + 15.24; f o r chamber (6 ) length i n cm.

L ' = 1.253 RT + 6.0; f o r chamber (6a length i n inches.

The equations r e s u l t i n a chamber length requirement o f about 20.8 cm (8.2 in . ) a t a nominal chamber pressure o f 68 atm (1000 psia). Scaling t o any chamber pressure r esu l t s i n :

L ' = 5.51 + 15.24; f o r chamber ( 7 ) length i n cm and PC i n atm

L ' = 2.17 J(mC + 6.0; f o r chamber ( 7 4 length i n inches and PC i n ps ia

2. Plug Cluster Engine

The base1 ine plug c l us te r engine i s composed of f i v e 02/H2 and f i v e 02/RP-1 modules a1 te rna te ly mounted on a olug. The t h rus t per module

KOM. DESIGN PO I NT

2 a t m (400 PsIA)

= 13.6 atm (200 PSIA)

6.8 a t m (100 PSIhj

O/F = 4.25

FIE % 703N (157 LBF)

= 6.8 atm (100 PSI)

= 68 atm (1 000 PSIA)

E = 2: l C

1 1 I I 1 1 1 I I 1 I I I I I 1 0 2 4 6 8 10 12 14 16 18 20 22 23 26 28 30

CHAMBER LENGTH, cm

Figure 30. LO?/RP-l/H2 Tri propei l a n t Engine Shear Coaxial Element Performance

92 1 I I I i I J 1.6 1.8 2.0 2.2 2.4 2.6 2.8

CHAMBER CONTRACTION RATIO, c C

NOM. DEI IGN POINT

NOM . DESIGN PO I NT

100

98

W

9 6 - W

94

= 2:1 - LF = 20.3 crn ( 8 IN.) A P ~ = nPf = .10 x PC

F/': % 703M (157 LBF) - O/F = 4.25

t

- O/F = 4.25

PC = 68 atm (1000 PSIA)

L ' = 29.3 cm (8 IN.)

AP, = b.8 atm (100 PSI) = APf - '/E c 703N (157 LBF)

92 I I I I 1

0 (400) (800) ( l l?OO) ( 1 600) (2000) CHAMBER PRESSURE, (!'CIA)

Figure 31. LO2/RP-l/H2 Tripropel l a n t Engine Shear Coaxial Element Performance Versus Contraction Ratio and Chamber Pressure

PRESSURE DROP FRCf'1 INJECTOh ;ACE TO PLENUM IN PERCENT OF PLENUM PRESSURE

A d 4

0 IU P m CO 0 IU P

I-- - .,.- .". . ,. -.-- - ,----.- '-v

I V , C, TCA Geometry Def ini t ions (cont.)

i s 8896N (2000 I b f ) and thrust s p l i t i s 0.5. The 02/H2 baseline module i s the ALRC Integrated Thruster Assembly (ITA) engine, as defined by the Uncon- ventional Nozzle Trade-Off Study (Ref. 3). The ITA, modified t o an a l l regen- e ra t i ve ly cooled conf igurat ion w i t h a 40: 1 norzl e expansion ra t io , w i 11 de l i ver 8896N (2000 l b f ) th rus t a t a chamber pressure o f 23.1 atm (340 psia). The fol lowing formula scales the 0 /H2 th rus t chamber radius f o r the study chamber pressure range o f 20.4 t o Q 8 atm (300 t o 1000 psia) :

RT = 4 m F x 2.44; f o r throat radius i n cm and PC i n atr,~.

(8)

RT = fna)lpc x 0.96; f o r throat radius i n inches and PC i n psia.

( 8 4

The nominal ITA chamber length i s 16-26 cm (6.4 inches) and the design contract ion r a t i o i s 3.3:l. The fo l iowing fornula was derived t o calculate chamber length for the study operating chamber pressure range:

L ' = 6.35 ~ I 3 7 ; + 9.9; ; f o r chamber length i n cm and PC ill a tn~

(9)

L ' = 2.50 A m C + 3.9; f o r chainber (9a ) length f n inches and PC i n pis

A vaporization 1 i m i ted performance c3l cul a t ion was conducted t o estimate the chamber length requirement f o r the 02/RP-1 nrodule. The ca l - cu lat ion indicated a 35.6 to 38.1 cm (14-15 inch) L ' would r e s u l t i n a t t a in - ment o f the p ?gram 98% ERE goal a t an operating chamber pressure of 20.4 atm (300 psia). This ca lcu lat ion agrees w i th the baseline 35.6 cm (14 inch) chamber length selected for the High Density Fuei Combustion and Cooling Investigation, Contract NAS 3-21030. A contract ion r a t i o of 3.3:l was also baselined f o r the 021RP-1 module. The fol lowing formula scales the chamber length f o r the study:

L ' = 6.68 mC + 30.46; for chamber length i n cm and PC i n atm.

(10)

L = 2.63 ,/Imc + 12.0; for chamber (lea) length i n inches and PC i n psia

Dual -Expander Engi ne 3. - - The central chamber f o r t h i s concept uses 1 i qu id / l i qu id propel -

l a n t in ject ion. This i n j ec t i on scheme i s s im i la r t o that employed on the 021RP-1 module o f the plug c luster . Therefore, the chamber length for the

I V , C, TCA Geometry Definit ions (cont.)

02/RP-1 engine o f the dual-expander concept i s specif ied w i th the formula previously developed for the plug c lus ter engine (equations 10 and 10a). The 0 /RP-1 chamber contraction r a t i o was selected t o be 3.3:l which i s f also dentical t o the plug c lus ter module value.

The gas/gas 021H2 in jec t i on f o r t h i s concept i s s imi la r t o tha t employed on the 02/H2 module of the plug c lus ter engine. Therefore, the plug c lus ter chamber length formula was u t i l ized f o r the dual-expander annular combustor (equations 9 and 9a).

A contraction r a t i o o f 3.3:1 was also selected for t h i s combus- t i o n chamber.

Further design guidelines were established f o r the chamber and nozzle contours. These guidelines were the resul t o f ALRC in-house studies and are as follows:

a. 02/RP-1 nozzle contour truncated a t an area r a t i o of 8.8:1

b. Annular inner wal l expansion ha l f angle 31 degrees; outer wal l expansion ha1 f angle 38.5 degrees.

c. Minimum wal l thickness separating combustors o f 1.02 cm (0.4 inches).

d. Outer wall contour (O2/H2) i s parabolic. The attach angle a t 02/RP-1 nozzle truncation plane i s 38.5 degrees. The nozzle e x i t ha1 f angle i s 11 degrees.

Typical dual -expander combustion chamber and nozzle g e a ~ e t r i e s are shown i n Figures 33 and 34, respectively.

D. STRUCTURAL ANALYSIS

Structural analyses were undertaken to determine the design constraints imposed by low cycle thermal fatigue and creep-rupture strength. These analyses were conducted i n conjunction w i th the coolant heat transfer evalua- t i o n to establ ish the chamber temperature, pressure and coolant channel geometry l i m i t s created by the chamber service l i f e requirements. For t h i s analysis the service l i f e between overhauls i s 300 cycles times a safety factor o f 4 (1200 to ta l cycles) or 10 hours accumulated run time.

LOX/

RP-

1 PC

= 6

8 at

m (

1 000

PSI

A)

LOX/

LH2

PC =

34

atm

(50

0 PS

IA)

Fs

= 0.

5

X (I

NCHE

S)

Fig

ure

34.

D

ual-E

xpan

der

No

zzle

Geo

met

ry

I V , D, S t ructura l Analysis (cont. )

The parametric s t r uc tu ra l analyses o f a1 1 three MMOTV engine concepts were conducted over the study chamber pressure and t h rus t spl i t ranges a t a base1 ine t h rus t l e ve l o f 88964N (20,000 1b).

The materi a1 used f o r the combustion chamber on-tubul a r por t ion ) i s zirconium copper w i t h mater ia l proper t ies assumed t o conform t o those shown on Figures 18 through 21. The low cyc le fa t igue data f o r zirconium copper ,das assumed i u have compressive ho ld t ime e f fec ts included, so no creep damage f r a c t i o n was used i n the low-cycle fa t igue analyses. The outer she l l o f the t r i p r o p e l l a n t and plug c l us te r engine chambers i s e lec t ro - formed n icke l w i t h adequate thickness t o remain e l a s t i c under the outward pressure and copper expansion forces. Total s t r a i n ranges i n the copper 1 i n e r could be reduced and fa t igue 1 i f e increased by f u r t he r opt imizat ion o f the she l l thickness bu t t h ~ s was beyond the scope o f these parametric studies. The cent ra l chamber o f the dual -expander engine has m i 11 - s l o t t ed copper channels on both sides o f an inner n icke l s t ruc tu re she l l . The outer annular chamber f o r the dual -expander engine i s a lso o f zirconium copper const ruct ion w i t h an electroformed n icke l she l l whose thickness was no t optimized.

The low cyc le fa t igue l i f e i s dependent upon the t o t a l s t r a i n range induced on the hot gas-side wa l l o f the regen-cooled t h rus t chamber. The la rge number o f chamber conf igurat ions and thermal loadings i n the parametric studies precluded the use o f f i n i t e element computer analysis a t each design po in t . A simp1 i f i e d s t r a i n p red ic t ion method was developed, based upon a s t r a i n concentration fac tor (K,), thermal expansion c o e f f i c i e n t (a), and the temperature d i f f e r e n t i a l between gas and backside temperatures (AT).

The value o f K, f o r a b i a x i a l l y constrained "hot spot" i n the p l a s t i c range i s 2.0 (Reference 13). F i n i t e element model computer so lu t ions for selected MMOTV conf igurat ions and previous studies (Ref. 2) a re p l o t t e d on Figure 35 and v e r i f y t h i s factor. Lower gas-side wa l l temperatures e x h i b i t lower KE values due to reduced p l a s t i c i t y and re1 i e f from outward def lec- t i o n o f the outer chamber she1 1 . Higher gas-side temperatures e x h i b i t h igher Kc values due t o less outward de f l ec t i on o f the she l l when the copper softens, and from uneven s t r a i n d i s t r i b u t i o n s when the copper l i n e r moves f u r t he r i n t o the p l a s t i c range and pressure-induced s t r a i ns become s i gn i f i can t .

The design curve ~f Figure 35 was used t o determine K, and Equation (11) was used t o p red i c t t o t a l s t r a i n ranges f o r the MMOTV regen-chambers. This s t r a i n range was then ctsn~pared t o copper low cyc le fa t igue al lowables o f Figure 20 to ensure a 1200-cycle 1 i f e (maximum s t r a i n range o f 2.15%).

0

LEGE

ND

0

HIG

H P

RESS

URE

ENG

INE

STUD

Y

0

MMOT

V CO

MPU

TER

RESU

LTS

- DES

IGN

CUR

VE

(REF

. 2

)

I I

I I

I I

1

(400

) (5

00)

(600

) (7

00)

(800

) (9

00)

(100

0)

(110

0)

1

TW

~

' G

AS-

SID

E W

ALL

TEM

PERA

TURE

-

(OF)

Fig

ure

35.

C

oppe

r C

hann

el

Str

ain

Co

nce

ntr

atio

n F

acto

r

I V , 0, St r t1~ t .u ra l Analysis (cont. )

Thermal stresses are sel f - equ i l i h r a t i n g and do no t s i g n i f i c a n t l y a f fec t strength margins o f safety. Mechanical (pressure) loads must be car r ied by the channels f o r the f u l l engine durat ion, however. The mechanical stresses were predicted by a three-hinge po in t method and compared t o y i e l d strength below the creep :egime. A f u l l y p l a s t i c l i m i t analysis was used i n the creep regime, and the stresses compared t o the lower 10- hour creep rupture strertgth. The most c r i t i c a l channel 1 ocat ion f o r mechan- i c a l stresses i s near the coolant i n l e t where near ly f u l l coolsnt pressure acts on high aspect r a t i o channels a t maximum temperatures. Since low aspect r a t i o s a t t h a t l o ca t i on would requi re a large number o f coolant channels and the 10-hour s t rength a t 867OK (llOO°F) i s estimated t o be very low, the gas-side tempera Lyres were I i n ~ i ted t o 81 1 O K (1 000°F).

The resu l t s of the analyses show tha t the low-cycle fa t igue l i f e requi re- ment 1 i m i t s the maximum temperature d i f f e r e n t i a l between the gas-side surface and the surrounding c ~ o l e r s t ructure. This (AT) value f o r the regeneratively-cooled t h rus t chambers i s shown i n Figure 36. f~taximum AT i s l i m i t e d by fa t igue l i f e f o r outer jacket surface temperatures below 394°K :250°F) and by engine dura t i cn f o r outs ide temperatures above 394OK (250°F).

The gas-side temperature i s l i m i t e d t o 811°K (10003F) as a r e s u l t of low 10-hour creep-rupture 1 i f e fo r copper. Higher temperatures would requi re the use o f many very narrow coolant channels, which i s f e l t t o be impract ica l . Enhanced creep damage e f f ec t s on the low-cycle fa t igue l i f e are a lso l i k e l y .

Coolant channel geometry i s 1 i m i ted by copper y i e l d s t rength a t low temperatures and creep-rupture 1 i fe a t elevated temperatures . The channel width/thickness (aspect r a t i o ) i s l i m i t e d by y i e l d s t rength a t gas-side wa l l temperatures up t o 700°K (800°F) and by cr2ep-rupture 10-hour 1 i f e a t higher temperatures i n the creep regime as shown on Figure 37.

E. THERMAL ANALYSES

Cooling analyses were conducted a t a Mode 1 t h rus t l eve l o f 88964N (20,000 l b ) . Parametric studies over a chamber pressure range from 6.8 to 136 atm (100 psid t o 2000 ps ia) and over a t h rus t spl i t range from 0.40 t o 0.80 were covered in d i f f e r e n t por t ions o f the study. The chamber pressure ranges, and t h rus t s p l i t rdnges considered for Mode 1 and Mode 2 operat ion of each of the engine systems i s summarized belcw:

ALLOWABLE AT = IWG - TBS

1200 CYCLES (300 X S.F. OF 4 )

10 HOURS DURATION

LIMITED BY 81 (lOOO°F) MAX GAS-SIDE TEMP.

STRAIN (LCF)

LIMITED

(-300) (-200) (-100) 0 (100) (200) (300) (400)

T~~ ' BACKSIDE TEMP. - (OF)

1 I I I I

100 200 3 00 4 00 503

T ~ ~ ' BACKSIDE TEMP. - O K

F igure 36. A1 lowable Temperature D i f f e r e n t i a l s f o r MMOTV Regen Chambers

I V , E, Thermal Analyses (cant.)

Mode 1 Thrust Engine Type Mode 1 PC Range Mode 2 PC Range S p l i t Range

T r i propel 1 ant 34-136 atm 6.8-81.6 atm .4-.8 (500-2000 ps ia ) (1 00-1 200 ps ia)

Plug Cluster 20.4-68 atm 20.4-68 atm . 5 (300-1000psia) (300-1000psia)

Dual Expander 34 t o 136 atm 17-68 atm .4-.8 (500-2000 ps ia) (250-1 000 ps ia)

The r e l a t i v e f e a s i b i l i t y o f the d i f f e r e n t engine systems was assessed based on the a t ta inab le chamber pressure, as determined by the respect ive pressure drop requirements.

Rectangular channel const ruct ion was used f o r a l l the engine chamber designs. A gas s ide wal l thickness o f .635 mn (0.025 in . ) , the minimum allowed by the study c r i t e r i a (Table X I? ) , was used wherever possible. Larger wa l l thicknesses were d ic ta ted i n some o f the designs because o f s t ruc tu ra l requi rements. The maximum gas-side wa l l temperatures were l i m i t e d t o 811°K (1000°F) because o f the 10 hour l i f e requirement. The gas-side wa l l thickness and wa l l temperature 1 im i ta t ions used i n t h i s study were presented i n sect ion IV,D.

A I 1 designs a re based on s t radd le -mi l l machining w i t h a constant land width o f 1.02 mn (0.040 in . ) . Based on channel opt imizat ion studies f o r hydrogen cool ing, the 4: l channel depthlwidth 1 i m i t of Table XI1 was used i n the th roa t region. Applying t h i s 4: l depthlwidth l i m i t a t the th roa t resu l ted i n the se lect ion o f the number o f coolant channels f o r most o f the designs. The channel w id th was no t allowed t o go below 1.02 mm (0.040 inches), however, and i n sonle designs t h i s l i m i t was used t o se t the number of channel s.

Methods o f .qnalysis - A two dimensional nozzle expansion performance analysis fo r a

chamber pressure o f 68 atm (1000 psia), 50/50 t h rus t s p l i t , exit = 400:l and the previously referenced TRAN 72 computer runs were used t o determine gas-side wa l l boundary layer proper t ies nesded i n the analyses o f the tripropel lant engines. Two dimensional nozzle expansion performance and TRAN 72 programs were a lso used f o r analyses o f the LOX/LH2 and LOX/RP-1 modules o f the plug c l us te r engine systems. Onc d i *onsional wa l l boundary layer proper t ies were used f o r the p lug sidewal l b,lalyses, and Cornel l data (Reference 14) were used f o r the p l ~ g base heat load approximation. One dimensional propert ies were a1 so employed i n the dual -expander engine systems analyses.

I V , E, Thermal Analyses (cont.)

Heat t ransfer from the combustion products t o the chamber wa l l was ca lcu la ted by the fo l low ing non-reactive formulat ion:

0.026 Cg pf ue Ref -0.2 Prf C (Taw - Twg)

p f

i n which s r r h ~ c r i p t i' r e fe r s tc, the f i l m temperature Tf, defined as Tf = 0.5 (Taw + Twg) w i t h of = pe T,/Tf and Ref = o f ue D/uf. The coe f f i c i en t Cg accounts for flow acce lerat ion e f fec ts and i s shown i n Figure 38 as a funct ion of area r a t i o .

The symbols used i n t h i s sect ion are def ined on Table X I V .

The design data were generated w i t h a regenera t i ve-cool i ng program s im i l a r t o the HOCOOL program (Ref. 15) constructed f o r NASA/Lewis under Contract NAS 3-17813. The opt ion designated WALL = 5 was used w i t h some added modif icat ions t o simulate two-dimensional cor~duct ion e f f ec t s and the spa t ia l va r i a t i on o f the coolant heat t rans fe r coe f f i c i en t . This option, shown schematical ly on Figure 39 represents t he ho t wal l , the 1 and and t h a t p a r t o f the external wa l l adjacent t o t+e channel as f i n s . That p a r t o f the external wa l l adjacent t o the land i s assumed t o be isothermal. The modified wa l l = 5 model establ ishes three co r re l a t i on coe f f i c i en t s which are appl ied t o the ho t wal l , the land, and the back wa l l separately. The f i l m c o e f f i c i e n t f o r the hot wa l l i s the groduct o f an inpu t f ac to r (HFAC) and the co r re l a t i on c o e f f i c i e n t evaluated a t a temperature which i s the average o f the wa l l temperature a t the center o f the channel (TWL 2) and the wa l l temperature a t the corner o f the channel (TCORN). Tne f i l m coef f ic ient f o r the back wa l l i s evaluated a t the back side wa l l temperature a t the center of the channel (TBS). The f i l m coe f f i c ien t which i s appl ied t o the land surface i s the product OF an inpu t f ac to r (GFAC) times the back wal l c o e f f i c i e n t p lus 1-GFAC times the ho t wa l l coef f ic ient . The se lect ion o f the HFAC and GFAC parameters p:-ovides a means of s imulat ing the actual coolant coe f f i c ien t va r ia t ion .

A l i m i t e d number o f two dimensional node network analyses using SINDA (Ref. 16) were perfhmicd a t the maximum heat f l u x l oca t i on near the throat . These studies accom?l ished the f o l lowing:

a. Provided t i le basis f o r determining the Wall = 5 s imulat ion parameters f o r hydrogen cool i ng .

b. Established the optimurri channel geometry f o r a f i x e d coolant f low area w i t h hydrogen cool ing.

A channel opt in i izat ion study was conducted t o de f ine the channel geometry which minimizes the loca l gas-side wa l l temperature f o r a f i x e d

TABLE X I d . - THERMAL AYA' "S I S NOMENCLATURE

English Letters

c9 Gas-cide hee t transfer correlation coefficient

C P

Specific hedt; F i s an integrated average between the coolant bul kPtemperature and the wall temperature

0 Local chamber diameter

h Factor applied to the coolant heat transfer coefficient evaluated a t the center1 ine wall temgerature to obtain the average coefficient f o r the gas-side wall

k Thermal ccnductivi t y

Yu Nussel t nunber

Pr Prandtl -t!nber

Re Reynold; ~,~rnber

T Temperature

u Axial velocity

Greek Letters

tc Viscosity

P density

fi Gas-side heat flux

Subscripts

aw Adiabatic wall

b Coolant b u l k or mixed mean temperature

e Frees tream

Film temperature. 0.5 (Taw + Tw)

w Coolant-side wall surface '

wg GES-side wall surface

wher

SCHEMATIC OF MODIFIED WALL = 5 MODEL

I I TINT I-+ External Fin TRS I , '1172

h = F [GFAC hL + ( I - s F I C ) ~ ~ ~ ] L2

Figure 39. Sche~i la t ic o f Modif ied Wal I = 5 Model

I V , E, Thermal Analyses (coi l t .)

.- . - . y pressurs gradient. This study assumed a l oca l th roa t s t a t i c pressure o f . . . 102 atm (1500 ps ia) , and a bulk temperature o f 11 1 O K (200°R). The heat - t rans fe r c o e f f i c i e n t f o r hydrogen i s greater a t lower wal l temperatures,

due p r i m a r i l y t o the f i l m y o p e r t ) e f f ec t s i n the Hess and Kunz co r re l a t i on

. . (Reference 17). The lanr! i s therefore a very e f f e c t i v e f i n and the maximum wa l l temperatures occ1:r a t t3e center o f the channel. Figure 40 presents the r e s u l t s o f the -+.annel o a t i r n i z ~ t i o n study. Channel depth i s p l o t t e d against c h a v n ~ l width w i t h l i n e s o f varying 'iand width superimposed. Two dimensional SINDP. network analyses w i t h a hot wa l l thickness o f .635 mn (0.025 i n . ) were used, and the r e s u l t i n g n~aximum wa l l temperatures are displayed on the f igure. The f i gu re a lso ind icates t h a t channel w id th a f f ec t s the maximum wal i temperature rnuch more than channel depth does. M i n i r i z i n g the land width f a r a given channel w id th reduces the maximum wal l temperatures pr imar i l y Gicause o f the channel depth reduct ion a1 lowed f o r a f i xed pressure gradient. Therefore, the cjtimum channel conf igurat ion has the channel width and land width minimized. The channel depth i s the design var iab le used t o ad just l oca l coolant ve l oc i t i e s . Use o f a 1.02 inn] (0.040 in . ) land i n the present desiqns instead o f the .762 mn (0.030 in . ) minimum allowed bv the study c r i t e r i a r esu l t s i n approximately a l l ° K (20°R) higher maximum wa l l temperature.

Simulation parameters HFAC and GFAC used i n the Wall = 5 model were also based on two dimensional SINDA network analyses. The coolant bulk temper- a ture used t o generate the parameters was s l i g h t l y higher, bu t the same general techniques were used. The maxirnun~ temperatures produced by the computer program used for t h i s analysis matched the SINDA r esu l t s whsn the HFAC parameter was set a t 1.0, ana the GFAC parameter was 0.5.

Curvature enhancement o f the cool ant f i l m c o e f f i c i e n t was included i n the t r i p r o p e l l a n t and plug c l us te r engine systems analyses. The dual-expander system analyses d i d no t include the enhancement e f fec ts . The enhancement o f the l oca l neat t rans fe r c o e f f i c i e n t dge t o chamber curvature was appl ied i n the same manner as aescr i bed i n Reference 18 fo r f r i c t i o n coe f f i c ien ts .

The e f i h ~ f i c e i i m t f ~ i the pur.i iur~ of the th roa t region where the b u ~ k moment~rrn i s being forced against the coolant s ide wa l l nearest the hot gas s ide i s expressed as [Reb (r . /~)2]0.05 where Reb i s the Reynolds number based upon the bulk propert ies, r i s the ins ide radius o f the loca l passage, and R i s the l oca l radius o f curvature o f the passage. Conversely, the por t ion o f the th roa t region where the bu lk momentum 5s f o r c i ng the coolant away from the hot gas side i s expressed as the fo l lowing m u l t i p l i e r [Reb ( r / ~ )2 ] - 0 .05 . For the purposes o f t h i s a ~ a l y s i s , on ly the heat t rans- f e r coe f f i c i en t o f the gas side 1 i q u i d wa l l was corrected. The other ~ a l l s of the passage were exempted from curvature e f f ec t s and t reated separately.

n - - W It II u U n

at-

n h n 0 br Lo

hh Q, e I-m hN cow 0- hl- el- m u tnv m u

( ' N I ) ' ~ l d 3 0 13NKWH3

I V , F, Thermal Analyses (cont.)

2. -- Chamber Wall Construction

Zirconium-copper was spec i f i ed as the gas-side wa l l mater ia l f o r a l l the chambers o f the engine systems analyzed. The analyses assumed a Nickel closeout o f .254 cm (0.10) inches i n a l l the designs. A s ing le design scheme was selected f o r a1 1 the chambers based on the imposed channel design constraints, the hydrogen cool i ng opt imizat ion study and fabr ica- b l i i t y . St raudle-mi l l machining, which y i e l d s 3 constant land width was selected as the primary fab r i ca t ion method. To s imp l i f y the analyses no b i f u r c a t i o n o f the coolant channels was assumed i n the nozzle regions of the chamber.

A constant land width o f . I02 cm (.040 in . ) was selected based upon the hydrogen cool i ng op~ i r ;~ : za t i on study conducted, and OMS engine design pract ice. While the op t i n i za t i on study ind icated a s l i g h t advan- tage i n using the minimum al lowable land width o f .0762 cm (C.030 in . ) , the OMS channel designs l i m i t the minimum land thickness to approximate . I02 cm (0.040 inches) t o insure adequate bond area on the land fo r the Nickel closeout process.

The niinimum allowable gas-side wa l l thickness of .0635 cm (0.025 i n . ) was used i n the designs whenever possible. However, the la rge channel widths encountered i n the nozzle regions o f some o f the chamber designs d ic ta ted wa l l thicknesses as la rge as .305 cm (0.120 i n . ) based on the s t r uc tu ra l requirements shown on Figure 37. These t h i cke r gas- s ide wa: 1 dimensions do not cause excessive pressure drop requirements because they on ly occur i n the low heat f l u x regions of the chambers.

Other channel geometry parameters which were determined f o r each design were the number o f channels and the channel depth ax i a l p ro f i l e . With the land width f i xed and the channel depth 1 im i ted t o fou r times the channel width, the maximuni l o r a l coolant f low area was set by the number o f channels. C!~annel opt imizat ion studies w i t h hydrogen cool ing ind icated tha t i t was desirable t o design a t the channel depthjwidth l i m i t of four . However, t h i s could be accomplished a t on ly one ax i a l pos i t i on i n most cases. A t o ther locat ions, i t was necessary t o s a t i s f y the thermal design z r i t e r i a w i t 5 lower d?pth/width r a t i o s o r t o overcool, i . e . , not reach the appl icab le wal l temperature l i m i t s . I n order t o avoid overcool ing i n high f l u x regions, the number o f channels i n each design was set by sa t i s f y i ng the design c r i t e r i a a t the th roa t w i t h a channel depth/ width r a t i o as c lose t o four t o one a s possible.

The ir~inimum channel width was l i m i t e d t o . I02 cm (0.040 i n . ) i n the study f o r p rac t i ca l f ab r i ca t i on reasons. This resu l ted i n a few chamber designs whereby the depth t o width r a t i o a t the th roa t f e l l below four t o one.


3. T r ip rope l lan t Engine Cooling Evaluation

T r i propel 1 ant engine designs combined three d i f f e r e n t methods o f th rus t chamber assembly fabr i ca t ion . M i l l - s l o t t e d zirconium copper channel construct ion was employed t o cool the chambcr from an e x i t area r a t i o o f 8:1 t o the i n j ec to r . A tube bundle constructed o f A-286 was then used from the 8:1 area r a t i o t o the appl icable rad ia t ion cooled nozzle t r ans i - t i o n area r a t i o .

The t r i p r o p e l l a n t engine cool ing schematic i s shown on Figure 41. This scheme was used t o evaluate the coolant pressure drop requirements over the e n t i r e range o f chamber pressures 34 t o 136 atm (500 t o 2000 psia), and th rus t s p l i t s , 0.4 t o 0.8. The coolant enters a t an area r a t i o of 8:l and flows counter t o the gases through the m i l l - s l o t t e d zirconium copper chamber. The t o t a l hydrogen f low e x i t s a t the in jec to r , i s brought back ex te rna l l y t o the tube bundle i n l e t mdnifold, and i s then used t o cool the two pass A-286 tube bundle nozzle from 8:l t o the rad ia- t i o n cooled nozzle t r a n s i t i o n point . The tube bundle nozzle was used t o conserve weight. An i n l e t area r a t i o o f 8:l was establ ished a t a t h r u s t chamber pressure o f 136 atm (2000 psia) and a t h rus t s p l i t of 0.5. The tube bundle t r ans i t i on area r a t i o could be var ied w i t h t h rus t s p l i t and chamber pressure. However, 1 le tube bundle pressure drop was very small (about 1% o f the t o t a l ) and hence, the a f f e c t o f the en t ry area r a t i o upon pressure drop i s small. Therefore, t o s imp l i f y the geometric scaling, the coolant i n l e t was f i xed a t an area r a t i o o f 8: l throughout the study.

Radiation cooled nozzle t r a n s i t i o n area r a t i o s are presented i n Figure 42. The attach po in t area r a t i o s vary as funct ions o f chamber pressure and th rus t s p l i t . FS-85 columbium w i t h an R512-E s i l i c i d e coat ing was selected as the nozzle mater ia l . Based on OMS engine design experience, a gas-side wal l temperature maximum o f 1617°K (2450°F) was used f o r the analyses.

A s ing le tube bundle design was invest igated and then ana l y t i ca l scal ing techniques were used t o estimate the pressure drops f o r the other chamber pressures and th rus t s p l i t s . Tube bundle pressure drops are generally small when compared t o the chamber pressure drops. Only the high th rus t s p l i t cases a t high chamber pressure r e s u l t i n tube bundle pressure dr;,)s greater than .54 atm ( 8 ps ia) . Table XV presents the tube bundle pressure drops f o r the tri propel 1 ant engines .

Table X V I and Figures 43 and 44 present the resu l ts o f the zirconium-copper chamber analyses. Table X V I presents per t inent design parameters as a function o f the Mode 1 chamber pressure and th rus t spl i t

LH2 t o

Preburners

Pump

Chamber

Tube Bundle Nozzle

Radiation Cooled Nozzle

1 - 1 Figure 41 . Tripropel l a n t Engine Cool ing Schematic

= 1617OK (2450°F) Twal COI ~ m b i um

140 , FS85 Colirrirbiurn w i t h R512-E S i l i c i d e C ~ a t i n g

n u

W Y

0 120 _ .,- c, (0 w

0

9

a#-

& V)

TI a C

40/60 Thrust S p l i t 0 50/50 Thrust S p l i t

0 80/20 Thrust S p l i t

F = 88964N (20,000 1 b )

E Exit = 400:1

( 500 (1 000) (1 500) ( 2000)

Chamber Pressure, PC, (ps ia )

t I 1 t 34 68 1 02 136

Chamber Pressure, atm

Figure 42. OTV T r i p r o p e l l ant Radiat ion Cooled rlozzle At tach Area Rat io

TABLE XV . - TRI PAOPELLANT ENGINE f UBE BUNDLE PRESSURE DROPS

Chamber Pressure, Tube Bundle Pressure Drop, - atm (psia) Thrust S p l i t Area Ratio atm (psi )

TABL

E X

VI.

-

TRIP

ROPE

LLAN

T EN

GIN

E CO

OLI

NG S

UMM

ARY

S.I

. U

NIT

S

Co

ola

nt

Inle

t a

t E

=

8:

1 T

~n

let =

50°K

=

811°

K

F =

8896

4N

Cha

mbe

r T

ota

l M

ax.

Pre

ssu

re

Th

rust

"C

hani

ber

AT

~u

l k 'c

ool

an

t H

eat

Load

, H

eat

Flu

x,

Max

N

umbe

r o

f M

qx

atm

S

pli

t a

tm

OK

-- -

kg/s

ec

K W

~/m

2

Mac

h N

o.

Cha

nnel

s D

B~

A-2

86

Tube

Bun

dle

Des

ign

E

= 8:

1 to

Rad

iati

on

Coo

led

Sk

irt,

E

=

150

T~~

= 86

7°K

m

ax

TABL

E XV

I (c

ont.

)

ENG

LISH

Uf4

ITS

Coo

lant

In

let

at E

=

8:1

T~

nl et

= 90

°R

T =

1000

°F

F =

20,0

00 l

b

"Gmx

Cha

mbe

r T

otal

M

ax

"cha

mbe

r A

T~

ul

k fi C

oola

nt

Hea

t Lo

ad

Hea

t Fl

ux

Pre

ssur

e T

hrus

t H

ax

Num

ber

of

Max

D

B~

(p

sia)

S

pli

t (p

sia)

(O

R)

(lb

m/s

ec)

(Btu

/sec

) (~

tu/i

n.*

-se

~)

Mac

hNo.

C

hann

els -

A-2

86

Tube

Bun

dle

Des

ign

,

E

= 8:

1 to

Rad

iati

on C

oole

d S

kir

t, E

=

160

T =

1100

°F

WGm

a x

(10001, COOLANT INLET

F = 88964N (20,000 LB)

( 1 1 I ( 500 ) (1 000) ( 1 500) (2000)

CHAMBER PRESSURE, (PSIA)

34 6 8 102 136 CHAMBER PRESSURE, atm

THERMAL

F igure 43. OTV T r i p r o p e l l a n t Chawber Pressure Drop

THRUST SPLIT

3 40160

A 50150

0 {0/20

I F = 88964N (20,000 L B )

( 1 ) I I I 1

(500) ( 1 000) ( 1 500) (2000) CHAMBER PRESSURE, (PSIA)

-- - -- -

34 6 8 102 136 CHAMBER PRESSURE, a cm

.- -. .

Figure 44. OTV Tr i propel 1 a n t Chamber Pressure Drop In, ! udi ng Tube Bundl e


f o r the nine chambers analyzed. The chamber pressure range covered i n t h i s study was from 34 t o 136 atm (500 t o 2000 ps ia ) i n Mode 1 operation. The Mode 2 chamber pressure range ran from approximately 6.8 t o 81.6 atm ,1@0 t o 1200 ps ia) . Mode 1 operat ion was used t o desfqn the chambers. Mode 2 O2!H2 operat ion i s less severe thermal ly becauLC, the coolant f low r a t e remains a corlstant and the chamber pressure i s reduced. Figures 43 and 44 present the pressure drop vs chamber pressure r e s u l t s f o r the zirconium-copper chambers on ly and chambers p l us A-286 tube bundles , respect i vel y . The ef fect o f t h rus t s p l i t upon pressure drop i s a lso displayed on these f igures. The highest pressure drops occur a t the highest t h r u s t s p l i t (80120). This occurs p r i m a r i l y because o f the lower coolant f low r a t e which r e s u l t s i n higher hydrogen bulk temperatures and thus, lower heat t rans fe r coeff i - c i en t$ f o r a given pressure gradient. However, the pressure drops for the 40160 t h rus t s p l i t cases are greater than f o r the 5C/50 t h rus t s p l i t cases. This i s caused p r ima r i l y by the s l i g h t l y more severe gas environment a t the lower t h rus t s p l i t . Even though tt:e coolant f low r a t e i s greater, the maximum heat f luxes and t o t a l heat loads are a lso groater than a t the 50150 t h rus t spl i t * jo in ts . The pressure drop versus t h rus t spl i t opt imizat ion po in t tDpears t o be l i m i t e d on the h igh t h rus t s p l i t s ide by the bulk temperature r i s e inf luence, and on the low t h rus t s p l i t s i d r by the higher heat fluxes and heat loads encountered.

Cooling o f the tri propel l a n t engine over the en t i r e t h rus t s p l i t a ~ d chamber pressure range i s p rac t i ca l .

4 . Plug Cluster Engine Cool - in$ Evaluation

The plug c lus te r engine cool ing schematic analyznd i s displayed on Figure 45. The hydrogen i s f i r s t used t o coo! the pluq, f lowing from the low area r a t i o regions t o the high area r a t i o regionq, and then across the base o f the plug. The hydrogen i s then brought back UP t o the LOX/LHz module &x i t s ( E = 40) and f lows up the noz7le through +.he th roa t region and chamber t o e x i t a t the i n j e c t o r . SPV : . : ~~ d i f fe ren \ ' coolant, f low paths were tested f o r the oxygen cool ing cases o f th:? I.OX/RP-: module. RP-i cool ing of the LOX/RP-1 module was a1 so invest igated.

During the course o f t h i s study, the r esu l t s from the Unconven- t i ona l Nozzle Tradeoff S t .~d j l (Ref. 3 ) showed t h a t i : i s des i rab le t o have the module ex i i s touch to ~l~axirnizc! performance. Tkis r esu l t s i n very high area r a t i o rnod..les. To minimfze the weight c f the module nozzle extensions, r a d i a t i r ) ~ ~ cooled nozzles are used. The follob!inc a+tackrnen+, area r a t i o s were established:


Thrust Radiat ion Cooled Nozzle

Chamber Pressure, Attachment Area Rat io

atm (ps ia) LOXIRP-1 Module LOX/LH2 Module

For these cases, the coo l ing sch..,natic i s essen t i a l l y the same as described except t h a t the hydrogen enters the module coo l ing jacket a t the above area r a t i o s a f t e r coo l ing the p lug base instead o f a t the module e x i t .

Results from the plug c l us te r engine design thermal analyses are presented i n Table X V I I and Figure 46. Table X V I I presents per t inen t design parameters as a func t ion o f chamber pressure. Thrust s p l i t was f i x e d a t 501 50. The f ou r cases invest igated included the H2 cooled LOX/LH2 modu'le, RP-1 cooled LOX/RP-1 modul e, 02 cooled LOX/RP-1 module and Hz cooled plug. Conclusive r esu l t s were obtained on ly f o r the Hz cooled cases f o r reasons t o be explained l a t e r i n t h i s section. Figure 46 displays the e f f e c t o f chamber pressure upon pressure drop for the Hz cooled LOX/LH2 mdol ue.

The LOX/LH2 module coolant channel designs a l l r e s u l t i n prac- t i c a l pressure drops. These resu l t s were obtained by assuming t h a t the piug surfaces would be cooled i n i t i a l l y fo l lowed by the module. This assumption resu l ted i n d i f f e r e n t coolant i n l e t temperatures f o r the module as a funct ion o f chamber pressure.

Detai led coolant channel designs f o r the p lug were no t pursued i n t h i s study. Prel iminary r esu l t s ind icated t h a t the pressure drops associated w i t h the plug were extremely low. Computer modeling of the plug was therefore done ov l y t o estimate the heat load associated w i t h the plug to obta in the bu lk temperature r i s e t o be used i n the module analyses.

RP-1 cool i ng the LOX/RP-1 mgdul e proved to be impract ica l because o f bulk temperature r i s e 1 im i ta t ions . The RP-1 coolant i n l e t temperature speci f ied i s 311°K (1CO0F) and a l i qu i d - s i de wa l l temperature l i m i t o f 589°K (600°F) i s required t o minimize cracking and coking o f the RP-1. These 1 i m i t s r e s u l t i n a p rac t i ca l bu lk temperature r i s e 1 i m i t o f 250- 278°K (450-500°F). The 02/RF-1 module employs a gas-generator cycle. I n order to meet the 98% combustion e f f i c i e n c y goal t h i s r e s u l t s i n chamber L ' values on the order o f 33 t o 3 3 cm (13 t o 15 inches). These long chamber lengths r e s u l t i n t o t a l heat loads which are 17 t o 30%

TABL

E X

VII

. - P

LUG

CLU

STER

ENG

INE

COO

LItiG

SU

MR

Y

S.I

. U

NIT

S

Th

rust

Sp

lit

= 50

/50

'~n

let "

2 =

T WG

Hax

81

1°K

F 1

889

64N

TIn

let O

2 11

1°K

TIn

letRP-

1 =

31 1°

K *

589°

K

T"t4

it~

(RP

-1)

Max

. C

ham

ber

El

Heat

a

x

~~

er

P

ress

ure,

A

P~

ha

mb

ers

AT

~u

l k

'~0

01

an

t *

Load

, M

ach.

o

f E

ngin

e T

ype

atm

at

m

OK

kg/s

ec

kU

W/rn

N

o.

Cha

nnel

s

LOX/

LH2

Mod

ule

20.4

0.

3 21

0 .2

49

855

18x1

!I6

.065

6 2

(cE

Xit

=

40

:l)

34

1.33

23

9 .2

49

319

29.6

~10

' .I

18

6

0

(In

let

@ E

=

40

:l)

68

23.1

26

4 .2

49

1024

5

7.7

~1

o6

.380

46

LOX/

RP-

1 M

odul

e 20

.4

- - 49

8*

.599

10

06

13

.9~

10

~ ---

--

RP-

1 C

oola

nt

34

-- 53

9f

.599

11

33

22

.7~

10

~ --

- --

('~

xi t =

40

:l)

(In

let

@ E

=

4031

)

LOX

Coo

lant

68

, - **

---

1.

86

- 48

.7x1

06

---

43

(cE

xjt

40

:l)

(In

let

@ E

=

40

:l)

Plug

20.4

c.

07

91

1.25

18

77

.65x

lo6

---

(tE

Ait

223:

l)

34

< .0

7 12

2 1.

25

2466

.9

8x10

6 ---

(

Inle

t@~

=4

0:1

)

68

<. 0

7 16

8 1.

25

4156

1

;196

x106

---

'B

ulk

tem

pera

ture

ris

e e

xcee

ds d

esi

gn

lim

it o

f 27

8OK

Wx

yg

en

co

ol f

ng

was

im

pra

ctic

al

beca

use

of

cool

an

t d

en

sity

cha

nges

enc

ount

ered

a

t th

e c

ri tl

ca

l te

mp

era

ture

and

/or

cri

tf ca

l p

ress

ure

po

ints

TABL

E XV

II (

co

nt.

)

ENG

LISH

UN

ITS

Thr

ust

Sp

lit

= 50

/50

T~

n~

et ' "O

R

T =

~OO

OO

F '%

ax

Tot

al

Max

. M

ax.

Num

ber

Cha

mbe

r H

eat

Hea

t M

ach

of

Eng

ine

Typ

e P

ress

ure

AP

~ha

moe

r AT

~u

l k

'coo

lant

Lo

ad

Flu

x N

o. C

hann

els

(psi

s)

(ps

ia~

(OR)

(lbm

/sec

) (~

tu!

(B~

u/

let)

in

2-se

c)

LOX/

LH2

Mod

ule

300

4.4

392

.55

81 1

11

.0

-065

G2

(E

~~

~~

=

4:

l)

500

19.5

a3

0 .5

5 87

2 18

.1

.118

60

(In

let

@ c=

40

:l)

1000

34

0 47

5

.55

97 1

35

.3

.380

46

.

LOX

/RP-

1 K

odul

e 30

0 -

- -

-.

896*

1.

32

954

8.5

RP-1

C

oola

nt

500

- 97

1f

1.32

10

75

13.9

-

-

( In

let

@ E

=

d0

:l)

\

*+

LOX

/RP-

1 M

odul

e 330

- -

4.10

-

9.2

- -

80

LOX

Coo

lant

10

00

- +w

-

4.10

-

29.8

-

43

(fE

Xi

= d0

:1)

(In

let

@ E

=

40:l

)

Plug

30

0 ~1

1 6

4 2.

75

1780

.4

-

- - -

(fE

xit

22

3:l)

50

0 c1

21

9

2.75

23

39

.6

- -

(In

let

@ c

= 4

0:l

) 10

00

<1

303

2.75

39

42

1.2

- -

* B

ulk

tem

pera

ture

ris

e e

xcee

ds d

esig

n li

rnit

of

SQflo

R

** O

xyge

n co

ol in

g w

as

irp

ract

ical

D

ecas

se o

f cc

clan

t da

nsi t

y c

hang

es e

ncou

n:cr

cd

at

the

cri

tic

al

tem

pera

ture

an

d/o

r'cr

f tic

al p

ress

ure

po

fnts

0 (200) (400) (600) (800) (1000) (1200) CHAMBER PRESSURE, ( P S I A )

(1000)

h

5 V)

% (100) ., Q

a

1 I I I I I I 0 19.6 27.2 40.8 54.4 68.0 81 $6

CHAMBER PRESSURE, atm

- .. - - - - - - H2 COOLANT

-

- - - -

Figure 46. OTV Plug Cluster LOX/LH2 Module Pressure Drop

W CI: 3 V) V) W CL n CY W m x 4 X U W

(10) 3 0 aE (u

x J -. X 0 J

- -

- - - - - - -


greater than those for the LOX/LH* modules a t the same chamber pressure even though the gas environment i s less severe. Bulk temperature r i s e values of 498 and 539°K (896 and 971°F) were obtained f o r the.20.4 and 34 atm (300 and 500 psia) PC cases, respect ively. RP-1 coolant heat t ransfer c o e f f i - c ien ts were determined from the Hines co r re l a t i on (Ref. 19).

Cxygen cso l ing o f the LOX/RP-1 module a lso p r w d t o be imprac- t i c a l . The oxygen cool ing cases a re af fected by a phase change a t low chamber pressures and by sh i f t s i n t ranspor t proper t ies near the c r i t i c a l temperature and pressure po in ts a t the higher chamber pressures. Oxygen c r i t i c a l temperature and pressure values are 1548°K (278.6"R) and 49.7 atm (730.4 psia), respect ive ly . With the 1.8 i n l e t pressure t o chamber pressure r a t i o spec i f i ed f o r gas generdtor cycles i n the study guide1 ines, the r esu l t i ng i n l e t pressures f o r chamber pressures o f 20.4 and 68 atm (300 and 1000 ps ia ) are 36.7 and 122.4 atrn (540 and 1800 psia), respect ively. The spec i f ied oxygen in1 e t temperature i s 11 1 O K (200°R). For the low chamber pressure point , 02 i s a compressed l i q u i d a t the coolant channel i n l e t . As the 02 passes down the coolant channels, the bu lk temperature r i ses u n t i l the sa tu ra t ion temperature i s reached and a phase change from a compressed l i q u i d t o a vapor begins. The corresponding sh i f t s i n the oxygen t ranspor t proper t ies great1 y reduce i t s cool i n g effectiveness u n t i l a t a po in t near the c r i t i c a l temperature, the pressure drop requirements become excessive. S im i la r l y , a t the high chamber pressure po in t the 02 i s supercr i t i c a l a t the coolant channel i n l e t , being above the c r i t i c a l pressure value bu t below the c r i t i c a l temperature value. As the coolant passes down the coolant channels the bu lk temperature r i s e s past the c r i t i c a l temperature value. This has no adverse ef fec t because on ly gradu31 s h i f t s i n t ranspor t proper t ies occur ?t pressures s i g n i f i c a n t l y above c r i t i c a l . As the bulk temperature continues r i s i n g and the coolant s t a t i c pressure drops, the oxygen cool i ng ef fect iveness decreases u n t i l the pressure drop requirements become excessive.

Therefore, i t appears t h a t oxygen cool ing a t the low chamber pressures i s l i m i t e d because o f the s h i f t i n t ranspor t proper t ies caused by the phase change from 1 i q u i d t o vapor. A t the high chamber pressure, i t i s l i m i t e d by the t ranspor t proper t ies changes associated w i t h the bulk temperature r i s e and a lso w i t h the coolant s t a t i c pressure degradation. Oxygen appears t o be an impract ica l coolant over the e n t i r e chamber pressure range covered a t t h i s 86964N (20,000 I b ) t h rus t l eve l . The r e l a t i v e l y low t h rus t t o chamber pressure r a t i o covered i n t h i s study, resu l ted i n low coolant f low r a t e per u n i t heat f l u x leve ls which l i m i t e d the f e a s i b i l i t y o f oxygen cool ing. Oxygen cool i ng was dropped from fu r t he r study ef for ts .

Oxygen cool ing heat t rans fe r coe f f i c i en t s were calculated based on the supercr i t i c a l oxygen heat t rans fe r co r re l a t i on o f Reference 20. Sub-cr i t ica l heat t rans fe r coe f f i c i en t s were evaluated using the same


co r re la t ion . No appl i cab le sub-cri t i c a l cool i ng co r re la t ions f o r oxygen were known t o ex i s t .

To continue the mixed mode p lug c l us te r evaluat ions i n the re - maining study tasks, RP-1 cool ing and a module chamber pressure o f 20.4 atm (300 ps ia ) was selected. This assumes t h a t impur i t i es can be removed from the RP-1 t o r a i se the bu lk temperature 1 i m i t above 589°K (600°F). The RP-1 module coo l ing analyses then proceeded assuming t h a t the coolant temperature was no t 1 i m i t i ng . This was done i n order t o ob ta in coolaat AP data a t the basel ine t h rus t l eve l and over a range o f th rus ts f o r use i n the power balance analyses and engine parametric studies. The resu l t s o f t h i s analyses a re shown on Figures 47 and 48. Even w i t h t h i s assump- t i o n a 8896N/module (2000 1 b ) t h rus t module design cooled w i t h RP-1 i s very marginal t o meet the l i f e requirements as noted by Figure 48.

Other po ten t ia l so lu t ions t o the HDF module coo l ing problem which might be considered i n f u t u re e f f o r t s i f the concept proves t o be a t t r a c t i v e f o r o ther reasons are:

O Reduction i n chamber 1 i f e goals.

O Reduction i n performance goals t o reduce chamber length.

O Consideration o f dump o r f i l m cooling.

O Hydrogen cooled OdRP-1 module.

Some of these approaches might be considered i n combination ra ther than a1 one.

5. Dual-Expander Engine Cooling Evaluation

The dual -expander engine cool ing schematic i s presented on Figure 49. The hydrogen f low i s s p l i t i n t o two paral l e l f low paths i n t h i s scheme. To opt imize the cool ing capab i l i t y o f hydrogen, i t i s necessary t o keep the coolant bulk temperature low when i t passes through the high heat f l u x regions. The dual-expander concept r e s u l t s i n three separate surfaces which must be cooled. Each o f these surfaces has a high heat f l u x ( t h roa t ) region instead of the s ing le region encountered i n a conventional chamber design. The se lect ion o f paral l e l f l ow paths per- m i ts the coolant f lowrate t o be s p l i t i n order t o minimize pressure drop. I n t h i s scheme, the smaller percentage of the t o t a l coolant f low i s used to cool the outer annular chamber wa l l . This coolant introduced a t the i n j e c t o r plane, f lows through the throat, and 2xi t s a t a manifold located i n the ,.. forced de f lec t ion nozzle extension. 'The cool ant f l owra te spl i t was chosen

RP-1 COOLANT

MODULE CHAMBER

I I I 1 I I I

0 ( 2 0 ) ( 4 0 ) ( 6 0 ) (80 ) $100) (120) TOTAL ENGINE THRUST, (LB X 10- )

Figure 47. Plug C l u s t e r LOXIRP-1 Module Coolant Jacket AP

MAXIMUM FOR CYCLE LIFE

P

Ew MODULE CHAHBER PRESSURE,

m atm ( P S I A )

C-

4

Figure 48. Plug Cluster LOX/RP-1 Module Coolant Bulk Temperature

Figure 49. Dual -Expander Engine Cool ing Schematic


t o keep the bulk temperature o f the coolant a t the forced de f l ec t i on nozzle e x i t a t approximately 756°K (900°F). The l a rge r percentage o f the flow i s brought from the cent ra l combustion chamber i n j e c t o r plane t o the throat, through the truncated nozzle, turns and f lows up the i ns i de wa l l of the annular chamber and e x i t s a t the i n j ec to r . I t i s the second t h roa t reg ion which l i m i t s the design.

Re;i~l t s from the dual expander engine design analyses a re d is - played i n Table X V I I I and Figure 50. Table X V I I I presents per t inen t design parameters as a func t ion o f chambw pressure and t h r u s t s p l i t . Figure 50 shows the required pressure drop as a func t ion o f t h r u s t s p l i t and chamber pressure.

Four d i f f e r e n t design po in ts were studied i n these analyses. Thrust s p l i t s o f 40% and 50% were evaluated a t central /annular chamber pressures o f 68/34 atm (10013/500 psia). The 50% th rus t s p l i t designs were also invest igated a t 102/51 and 136/68 atm (15001750 and 2000/ 1000 psia) central /annular chamber pressures. The 80% th rus t s p l i t values were a1 so invest igated. For the chamber pressure range used i n t h i s study, regenerative cool i n g f o r the 80% th rus t spl i t designs proved impract ica i because o f bu l k temperature r i s e 1 im i ta t ions .

The 136/68 atm (2000/1000 ps ia) design po in t resu l ted i n imprac- t i c a l coolant ve l oc i t i e s which exceeded sonic ve loc i t y . It appears t h a t there are two sets o f const ra in ts which l i m i t the dual-expander engine design concept. They are bulk temperature 1 i m i t s and coolant Mach number 1 im i ts . The gas-side wa l l temperature must be 1 im i ted t o a maximum value o f 811°K (1000°F) i n order t o meet the cyc le 1 i f e requirements. This i n t u r n impl ies a p rac t i ca l coolant bulk temperature l i m i t o f roughly 756- 783°K (900-950°F). When the coolant flow r a t e t o the t o t a l heat load r a t i o gets too low, a bulk temperature problem ex is ts . This i s the case f o r the 80% th rus t s p l i t l e ve l . Coolant Mach number l i m i t a t i o n s must be appl ied i n order t o minimize l oca l ve l oc i t y e f f ec t s and shock wave phenomena.

An appropr iate bulk temperature r i s e l i m i t l i n e i s shown on Figure 50. Appraoximate coolant Mach number l i m i t a t i o n l i n e s are a lso p lo t ted. The coolant Mach No. o f 0.5 i s the more p rac t i ca l l i m i t i n g case. The 1 i m i t i n g 1 ines roughly out1 i ne the acceptabl e/nonacceptable design l i m i t s f o r a 88964N (20,000 1 b) t h rus t engine. A t the low chamber pressure point , 34 atm (500 psia), p rac t i ca l designs can be achieved for t h rus t s p l i t s ranging from 40% t o roughly 70%. As chamber pressure i s increased however, the acceptable t h rus t s p l i t range must be reduced. A t 68 atm (1000 psia), t h rus t s p l i t s ranging from 40% t o roughly 60% dould prove feasible. The max ,num chamber pressure values for 50% and 40% t h r u s t s p l i t s are roughly 88.4 and 102 atm (1300 and 1500 psia), respect ive ly . Any chamber pressure design above 102 atm (1500 ps'a) appears t o be unacceptable f o r the range o f th rus t s p l i t s studied w i t h i n the design guide1 ines assumed a t the base1 i ne t h rus t 1 eve1 .

S.I

. U

NIT

S

Tot

al

Cha

mbe

r A

A

T

\j

Hea

t C

ham

ber

Pre

ssu

re,

Th

rust

C

ham

ber,

Bul

k C

oola

nt

Loa

d,

Sec

tf o

n .-

atm

Sp

l f t

OK

kg/s

ec

KU

ah

-

Cen

tral

Com

bust

ion

68

40/6

0 1.

48

162

.962

25

81

Ann

ular

In

sid

e 34

3.

02

153

.962

22

65

Ann

ular

Ou

tsid

e 34

4.

05

708

.544

58

76

Ov

eral

l E

ngin

e 68

/34

4.50

45

7 1

.SO

6 10

722

Cen

tral

Con

~bus

tio

n

68

50

/50

1.68

26

6 .6

35

2729

A

nnul

ar

Insi

de

34

8.15

23

8 .6

35

2330

Ann

ular

Ou

tsid

e 34

1.

82

627

.621

59

53

Ov

eral

l E

ngin

e 68

/34

9.83

56

5 1.

256

1101

2

Cen

tral

Com

bust

ion

1 02

50/5

0 6.

53

287

.'Of3

32

74

Ann

ular

In

sfd

e 51

39

.05

1 92

.708

25

37

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ular

Ou

tsid

e 51

1

.44

708

.544

59

24

Ov

eral

l E

ngin

e 1 O?/ 5

1 45

.58

578

1.25

2 11

735

Cen

tral

Co

mb

ust

ion

13

6 50

/50

17.2

1 29

2 .7

08

3361

Ann

ular

In

sid

e 6

8

- .7

08

2707

Ann

ular

Ou

tsid

e 6

8

48.3

70

9 .5

44

6067

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eral

l E

ngin

e 13

6/68

c

- 1.

252

1213

5

*Coo

lant

Mac

h no

. ex

ceed

ed 1

.0

Ma%.

Wc

b.

Nvn

~ber

of

U/n

Cha

nnel

s Icr

'o. -

--

TABL

E XV

III

(co

nt.

)

ENG

LISH

UN

ITS

Chamber

Chamber Section

Pressure

(psi

s)

Central Combustion

1000

Annular

Inside

500

Annular Outside

500

Overall Engine

1000/500

Thrust

Spl i t

AP~hamber

(psis)

Total

flax

Heat

Heat

~u

l

k 'coolant

Load

Flux

(*9

! (lbd

(Btu/

(B$u/

sec)

sec)

in

- -

--

set)

Max

Mach

No. -

.I75

-166

,207

.207

Number

of

Channel s

74

-

158

220 -

Central

Combustion

1000

50/50

24.7

479

1.40

2583

24.1

-165

92-

Annular

1cs:de

509

119.8

429

1.40

2210

24.6

1 172

4nnular Outside

500

26.8

1128

1.37

5646

24.4

.188

226

Overall Engine

1000/500

144.5

1017

2.77

10464

24.4

.dl8

- Central Combustion

1500

50/50

96

51 6

1.56

3105

36.2

-302

80

Annular Inside

750

574

365

1.56

2406

36.8

.a83

160

Annulst

Outside

750

227

1275

1.20

5619

36.8

.dl9

192

Overall Engine

'1 500/750

67 0

1041

2.76

11130

36.8

-883

- -

Central Combustion

2000

50/50

253

525

1.56

3188

47.2

.a92

70

Annular Inside

lo00

-*.

- 1.56

2507

49.2

~1.0

130

Annular Outside

lo00

71 0

1268

1.20

5754

49.2

-768

172

Overall Engf ne

2000/1 000

- * -

2.76

11509

49.2

~1.0

-

i

- I

I?

*Coolant Mach no.

exceeded 1.0

F H2 COOLANT

BULK TEMPERATURE R I S E L I M I T

THRUST S P L I T

0 40/60

( lo) i I I J ( 5 0 0 ) ( 1 0 0 0 ) : 1 5 0 0 ) ( 2 0 0 0 )

CENTRAL COMBUSTION CHAMBER PRESSURE, ( P S I A )

34 6 8 1 0 2 1 3 6 CENTRAL COMBUSTION CHAMBER PRESSURE, atm

F igure 5 0 . D u a l -Expander Engine C o o l a n t P r e s s u r e Drop

SECT ION V

TASK 111 - BASELINE ENGINE CYCLE, WEIGHT AND ENVELOPE ANALYSIS


The objectives of t h i s task were t o determine the engine system pressures, temperatures, and delivered performance f o r each of the baseline d1V engine concepts previously described i n Tables V, V I and V I I . For each o f the baseline concepts described by the schematics shown on Figures 1 through 6, point design sumaaries o f Mode 1 and 2 operation were established. These sunmarizes include the cycle schematic, del ivered specif ic Smpul se, engir:e system weight flows, pressures and temperatures, pump and turbine speeds, e f f i c ienc ies and horsepowers, engine system #eight and overa l l envelope dircensions. Cool -,its and cool i ng schemes used i n t h i s task are as defined i n Task 11, Section I V . Each of the baseline concepts were analyzed t o determine the maximum Mode 1 and Mode 2 chamber pressure attainable w i th in the constraints o f the cycle power 1 i m i t, thrust chamber thermal fat igue 1 i m i t, propel lant property l i m i t o r a b i l i t y o f components to operate a t both Mode 1 and Mode 2 design conditions.

Engine cycle power balances were performed a t the baseline th rus t level o f 88964N (20,000 lb) . Engine performance data were evaluated f o r a combus- t i o n e f f i c iency o f 98%. Simplif ied JANNAF performance prediccion techniques (Ref. 21) were used t o determine the other performance losses. The boundary layer loss charts i n the simp1 i f i e d procedures were adjusted t o agree w i th the l a tes t experimental data obtained a t area r a t i o o f 400:1, a th rus t level o f 88964N (20,000 1 b) and 136 atm (2000 psia) chamber pressure (Ref. 22). For these tes t conditions, the experimental data indicates tha t the o l d procedures predicted a boundary layer loss approximately 4 secs too high.

Addit ional study guide1 ines are as fol lows:

O System Pressure Losses (~PlPups tream)

Injectors:

L iquid - 15% (minimum) Gas - 8% (minimum)

Val ves :

Shutoff - 1% Liquid Control - 5% (minimum) Gas Control - 10% (minimum)

V, A, Objectives and Guidelines (cont.)

O Boost Pump Drive Requirements

Boost pumps are not evaluated i n the power balancing. However, appropr iate main pump i n l e t condi t ions were ca l - cu la ted and main pump horsepower penal t ies o f 3% were assumed t o account f o r the f low requi red f o r hyd rau l i ca l l y dr iven boost pumps.

RPM) (m3/sec)1'2 S = 387 ( (ld3l4

(maximum) S I Un i t s

S = 20,000 ( R P M ) ( G ~ ) ~ / ~ (maximum) Engl i s h Uni ts ( f t ) I4

O Maximum Bearing DN Values (Ro l le r and B a l l )

LH2 Pump - 2 x l o 6 (RPR) (mm)

LOX Pump - 1.5 x l o 6 ( R P M ) (rm) RP-1 Pump - 1.8 x l o 6 (RPM) (mn)

" Minimum Bearing Size: 20 mn

O Turbine I n l e t Temperatures

LH2 TPA - 1033OK (1860°R) (Fuel-Rich 0Z/H2 Dr ive Gas)

LOX TPA - 922OK (1660°R) (Ox-Rich 0p/H2 O r i #e Gas)

R P - I TPA - 1089'K (1 960°R) (Fuel-Rich 02/RP-I Dr ive Gas)

B. ENGINE SYSTEM EVALUATIONS

1. T r i propel 1 ant Engine

Engine power balance analyses were conducted a t the basel ine !lode 1 t h rus t l eve l o f 88964N (20,000 l b ) and a t h rus t s p l i t o f 0.5. The e f f e c t o f t h rus t s p l i t was a lso established. The t r i p r o p e l l a n t engine system considered i n these evaluations i s shown schematical ly on Figures 51 and 52. Power balances were conducted as a funct ion o f t h rus t chamber pressure over the e n t i r e study range o f 34 t o 168 atm (500 t o 2000 ps ia )

Figure 51.

Mod

e 1 Tripropellant

Engine S

chem

atic

FRm

FP

.m

800S

T BO

OST

PL

W

HYDR

OGEN

a OR

IFIC

E:

7- O

XYG

EV

C04

(8U

STIO

N P

RC

DU

rn

SHU

T OF

F VA

LVE

CHEC

K VA

LVE

PB

PREB

URNE

R P

PUMP

T

TURB

INE

TC TH

RUST

CHA

MBER

Fig

ure

52.

Mod

e 2 Tr

ipro

pell

ant

Eng

ine

Sch

emat

ic

V, 0, Engine System Evaluations (cont.)

because the Task I 1 resul ts d id not show t h i s concept t o be cooling l imited. The resu l ts of the Task 11, cooling evaluation provided the necessary coolant jacket pressure drop data f o r use i n t h i s analysis.

Prel i m i nary turbopunip analyses were conducted i n i t i a l l y t o estab- l i s h component e f f i c ienc ies t o b used i n further evaluations. The main pump speeds were evaluated as a function of pump discharge pressure w i th in Ihe Learing t':l and suction specif ic speed constraints. The number of pump stages were selected t o maintain a pump speci f ic speed (Ns) greater than [600 (RPM) ( G P M ) ~ / ~ / ( ~ ~ ) 3 / 4 ] t o get reasonable ef f ic iencies . Pump t i p speeds and impeller diameters were calculated w i th the a id of Figure 53 and pump efficiency estimates were made from Figures 54 and 55 which are based upon data i n Reference 23. Results o f pre l iminary calculations, which formed the foundation f o r fur ther power balancing, are shown on Table X I X .

Turbine ef f ic iencies were estimated as:

LH2 TPA - 809

LOX TPA - 75%

RP-1 TPA - 75% Pump discharge pressure requirements are shown as function o f

thrust chamber pressure on Figure 56 f o r a th rus t s p l i t of 0.5. The f igure shows tha t the LOX pump discharge pressure requirements are approximately equal t o those of the hydrogen TPA. A l l o f the oxygen i s pumped to high pressure t o meet the preburner and turbine i n l e t pressure requirements. Both the hydrogen and oxygen pump discharge pressures are functions of the thrust chamber pressure, cool ant jacket pressure drop and turbine pressure r a t i o requirements. The RP-1 pump discharge pressure i s p r imar i l y only a function o f the chamber pressure and turbine pressure r a t i o . A l l of the RP-1 i s combusted i n a fue l - r i ch preburner. Figure 56 also shows tha t the cycle i s not power balance 1 i m i ted. Therefore, a th rus t chamber pressure of 136 atm (2000 psia) was selected as a baseline f o r generating the engine operating specif ications .

The t r ipropel l a n t engine and component Mode 1 operating specif i - cations, for a thrust chamber pressure o f 136 atm (2000 psia), are shown on Table X X . The pressure budget f o r t h i s engine which resulted from the study guidelines and power balance analysis i s shown on Table X X I . From t h i s table, i t can be noted tha t the power balance i s governed by the LH2 TPA turbine pressure ra t io . The Mode 2 operating conditions f o r t h i s engine and components are shown on Table X X I I . This preliminary design analysis indicates that the component operating parameters f o r both Mode 1 and 2 are reasonable. The pressure schedule for Mode 2 operation i s shown on

Ns*

SP

EC

IFIC

SPE

ED,

(RPM

) (G

PM

) '12

/(~

~)

3/4

200

300

500

7 00

1000

20

00

3000

50

00

7000

I I

1 I

I I

I I

' 0.7

- - 0

.6

- - 0

.5

u z L

L

LL

W

0

C)

S,

SUC

TIO

N S

PE

CIF

IC S

PEED

=

- 0

- 0.

4 ;5

387

(RPM

) (m

3/s)

1'2

/(m

)3/4

I

20,0

00

(RPM

) (G

PM

) 1/2

/(~

~)3

/4

L

I I

4 5

6 7

8 9

10

12

14

16

18-2

0 3 0

40

50

60

70

80

90

100

120

Nss

SP

EC

IFIC

SPE

ED,

(RP

M) (m

3/s)

1/2/

(m)3

'4

Fig

ure

53.

H

ead

Co

eff

icie

nt

vs S

pe

cif

ic S

peed

an

, RE

FERE

NCE:

L

IQU

ID R

OCKE

T EN

GIN

E CE

NTRI

FUG

AL F

LOW

TU

RBO

PUM

PS,

NASA

SPA

CE V

EHIC

LE D

ESIG

N

CR

ITER

IA M

ONOG

RAPH

, NA

SA S

P-81

09,

FIG

. 6

DEC.

19

73.

IMPE

LLER

T

IP D

IAM

ETER

CM

(I

N.)

/~ /

/ /

/ 40

. I

J I

I I

I 1

400

600

800

1000

15

00

2000

30

00

Ns

SP

EC

IFIC

SPE

ED,

(RPM

) (G

PPI)~

/'/ (

FT)

3/4

1

I I

I

I I

1 I

I

6 8

10

15

2

0

30

40

50

60

N,,

SP

EC

IFIC

SPE

ED,

(RP

M)(

H~

/SE

C)~

/*/(

M)~

/~

Fig

ure

54.

In

f7u

ence

of

Pum

p S

ize

Upo

n E

ffic

ien

cy

I-

I I

I 1

I

I 0

2

4 6

8 10

12

14

16

IM

PELL

ER T

IP D

IAM

ETER

, CM

90

80

70

- >

2 - W

e4

z 6

0-

W

50

406

Fig

ure

55.

Pu

mp

Eff

icie

nc

y v

s Im

pel

ler

Tip

Dia

met

er

- Ns,

SP

EC

IFIC

SPE

ED,

(RP

M) (G

PM

)"*/

(FT

)~/~

'

1/2

3/4

RPN

(m3

/s~

c)

/m

(200

0)

38.7

(1

500)

29

.0

(120

0)

23.2

(100

0)

19.4

(9

00)

17.4

(800

) 15

.5

(700

) 13

.6

- (6

00)

11.6

I

1 I

I

(1

I (2

) (3

) (4

) '(5

) .(

6)

IMPE

LLER

TIP

DIA

MET

ER,

(INCH

ES)

TABL

E X

IX . -

PR

ELIM

INA

RY

TRIP

ROPE

LLAN

T EN

GIN

E PU

MP

AN

ALY

SIS

S.I

. U

NIT

S

Th

rust

= 8

8964

N

Th

rust

Sp

lit

= 0.

5 N

ozzl

e A

rea

Ra

tio

= 4

00

Mod

e 1

Th

rust

Cha

mbe

r P

ress

ure,

at

m

To

tal

Eng

ine

Flo

w R

ate,

kg

/sec

Oxy

gen

Flo

w R

ate,

kg

/sec

Hyd

roge

n F

low

Rate,

kg/s

ec

RP-1

F

low

Rat

e,

kg/s

ec

LOX

Pum

p LH

2 Pu

mp

RP-

1 Pu

mp

Dis

char

ge P

ress

ure,

at

m

68

136

306

81.6

15

0 30

6 68

13

6 30

6 3

Vo

lme

tric

Flo

w R

ate,

m

/sec

-0

1 57

.015

7 .0

155

.017

6 .0

175

.Dl7

4 ,0

0372

.0

0370

.0

0367

Su

ctio

n S

pe

cif

ic S

peed

, (R

PM)

387

(m3/

sec)

1/2/

(m

)3/4

Net

Po

sit

ive

Su

ctio

n P

ress

ure,

at

m

3.02

Net

Po

sit

ive

Su

ctio

n H

ead,

m

27

.5

Spe

ed,

RPM

37,0

60

To

tal He

ad R

ise,

m

59

1

No.

of

Sta

ges

1

2p

eci

fic

Spe

ed,

(~

~~

)(

m~

/s

ec

)~

/~

/(

m)

~/

~

38.7

Hea

d C

oe

ffic

ien

t .4

6

Tip

Spe

ed,

m/s

ec

112

Imp

ell

er

Dia

met

er, a

5.77

Pun

p E

ffic

ien

cy

, X

64

TABL

E X

IX (

con

t.)

ENG

LISH

UN

ITS

-.

Mod

e 1

ntu

st

Cha

mbe

r- P

ress

ure,

p

sfa

T

ota

l E

ngin

e F

low

Rat

e,

1b/s

ec

Oxy

gen

Flo

w R

ate.

I b/

sec

Hyd

roge

n F

lw R

ate.

lb

/se

c

RP-

1 F

low

Rat

e.

lb/s

ec

Dis

char

ge P

ress

ure,

p

sia

Vo

lum

etr

ic F

low

Rat

e.

GPH

Su

ctio

n S

pe

cif

ic S

peed

. (R

DM

) (G

PM

)'/~

/(F

T)~

/~

Set

Po

sit

ive

Su

ctio

n P

ress

ure,

p

sia

X

et

Po

sit

ive

Su

ctio

n H

ead,

f

t

Spe

ed,

RPM

To

tal

Hea

d 2f

se.

ft

No. of

:tage

s

Sp

aii

fic

Spe

ed.

(RW

) (G

PM

)'/~

/(F

T)~

/~

Hea

d C

oe

ffic

ien

t

Tip

Spe

ed,

ft/s

ec

In~:

.elle

r T

ip D

iam

eter

. in

ches

Pgm

p E

ffic

ien

cy

. X

Th

rust

= 2

0.00

0.

Th

rust

Sp

lit - 0.5

Noz

zle

Are

a R

ati

o =

400

LOX

Pum

p

2000

248.

3

20.0

00

88.8

180

62.3

70

3.87

6 1

2000

.46

521

1.91

62.5

LH2

Pum

p

2200

277.

5

8,00

0

37.7

1234

10

0,00

0

70,7

70 3

875

.578

1146

2.62

56.5

RP-

1 P

unp

2000

45

00

58.6

5 58

.11

20.0

03

20.0

00

38.9

38

.6

112.

1 11

1.5

90.0

00

90.0

00

5,65

9 12

.880

1 2

1056

9 5

4

-555

.5

7

573

603

1.46

1

-54

57.5

56

MODE 1 THRUST

THRUST = 88964N (20,000 LBS) SPLIT = 0 5 TURBOPUMP

(500) I I 1 I I

( 0 ( 500 ) (1000) (1500) (2000) (2500) THRUST CHA'rliJER PRESSURE, (PSIA)

0 20 40 60 80 100 120 140 160 180 THRUST CHAMBER PRESSURE, atm

Figure 66. Tripropel l a n t Engine Pump Discharge P~*essure Requirements

TABL

E XX

. - T

RIPR

OPE

LLAN

T EN

GIN

E O

PERA

TING

SPE

CIF

ICA

TIO

NS

lH2

LO

X R

P-1

1u

rbo

p.p

rv

rboprr

p

Tur

bopl

lp

E_rmlr

YH

~U

Th

rust

. Il

vu

um

Sp

eci

fic

I.~

!se

. s

tc

To

tal

Flw

Rate.

kp

lsu

Ov

cra

ll I

lla

ture

Ra

tio

Inle

t P

ress

ure,

a

b

183.

1 17

9.1

175.

2 In

let

Ta

pc

ratu

re.

'K 10

33

922

1089

G

as

Flw

Rat

e.

kg

/su

1

.a41

15

.848

3.

9%

bs

Pro

pe

rtie

s

Cp.

Sp

ec

ific

Hea

t a

t C

on

sta

nt

Rcs

sure

. 2.

19

0.27

7 0

.m

ca

1lg.

K

Fra

cti

on

of

LHZ

to T

ota

l F

ue

l F

lw

Oxy

gen

Flw

Rat

e.

kg

/su

Hyd

roge

n F

low

Lte

. k

gls

u

RP

-1 fl

w P

ate.

k

gjs

u

r. R

ati

o o

f S

pe

cffi

c H

eats

sh

aft

~o

rs-r

'l).

.HP

Eff

icie

nc

y.

2

Pre

ssu

re O

tie

!'io

ta1

to

Sta

tic

) T

hru

st C

hd

cr

Vac

uun

Th

rust

. I(

Vac

uun

Sp

eci

fic

lap

uls

e.

su

Ch

rbc

r P

ress

ure.

a

m

No

zzle

4.m

Lt

io

(IJ

x

bh

ors

ep

acr

pe

rult

y f

or

bo

ost

fnm

p h

yd

rau

lic

tu

rbin

e d

riv

e fla

.

L"2

LOX

0-

1

!!!Ee

!!@E

!%Q

Ov

era

ll M

ixtu

re R

ati

o

4.25

Tn

roa

t D

imte

r, a

Ch

wb

cr D

irc

ttr.

cm

Ilo

zzle

Ex

it D

irc

ter.

cu

too

lan

t Ja

cke

t LH

2 F

low

Rat

e.

kpls

ec

Co

ola

nt

Inle

t T

empe

ratu

re.

'l(

Co

ola

nt

Ex

it T

ap

crra

turc

. 'K

Co

ola

nt

~a

ck

et :.P

. rt

m(1

)

Sp

wd

. rp

ll

Dis

chb

rge

Pre

ssu

re. st

. H

ead

Ris

e. l

Nm

be

r o

f S t

aw

s

5w

cif

ic

spee

d (I

tS).

(~

~)1

)(m

~/s

ec

)~/~

(m)~

/~

Hc+

d to

cff

lcic

nt

llpclltr T

ip S

pe

d.

Ws

u

Iwe

lle

r T

ip D

lrc

ter,

a

Inje

cto

r G

as F

low

Rat

es.

kq

lsu

02/H

2 F

ue

l-R

ich

O

2/H

O

xid

ize

r-R

ich

~~

/Rb-

l Fue

l-R

lch

rw

Copp

er C

-r an

d lu

be

Bun

dle

Pre

ssu

re O

mp

Ozl

RP

- 1

Eff

icie

nc

y.

2 F

wl-

Ric

h

we

igh

t m

d E

nrc

lop

c 17

5.2

Ch

..b

cr

Pre

ssur

e.

atm

-sti

on

T

cnp

cra

ture

. '1:

10

89

En

gin

e Y

clp

ht

= 2

Y.7

kg

0.37

E

ng

ine

Lm

gth

:

1.07

5 E

xte

nd

ible

llo

ule

Dcp

loye

d =

241.

8 u

Ext

en

dib

le l

lozz

le S

tac

d

= 16

9 =

2.

907

En

gin

e ~

zz

lt

F

-+-

:., 12

5.2

ra

Mix

ture

Ra

tio

ox

Flo

w b

te.

kg

/su

Fu

el

Flw

Rat

e.

kpls

cc

TAB

LE X

X (c

on

t . )

ENG

LISH

UNITS

LOX

IC-1

T

urbo

- lu

rboW

26

33

2575

16

60

1960

34.9%

a. ?a

Lw

le

Va

cum

Th

rust

. lb

In

let

Pre

ssur

e.

ps

i*

Inle

t T

eq

x-ra

ture

. *R

G

as F

l~

l

Rat

e,

lbls

ec

bs

Pro

pe

rtie

s

Vac

uum

Sw

cif

is

lwa

lse

. se

c

l0:~

l F

led

Rat

e.

Ib/s

ec

Ov

err

ll M

ixtu

re K

~t

io

Fra

ctio

n o

f L

IZZ

to i

o:r

l F

uei

F1.w

Oljg

en

Flw

Rs'

e.

lbis

ec

Hy

dr~

~e

tl

Flbw !&

tt..

Ib/s

ec

R1 -1

F

lc-

RJ

?~

. lb

,'sr

c

Cp.

S

pe

cifi

c H

e3t

at

C~n

;:3nt

P

re%

s~

re.

2.19

B

tu/l

b "

R

I.

Ra

tio

of

Zw

cif

sc

Hea

ts

1.35

8 Sh

a?:

Ho

rs

e~

~e

r"

;

1024

~f

fr

ci

m~

~.

r

80

Pre

ssu

re R

ati

o {

To

tal

to S

tatl

cj

1.23

8

m -In

clu

de

s 3:

ho

rre

~o

ne

r pen

al t

y f

or

bo

ost

pu

m~

hy

dra

uli

c

Ckn

nhcr

Src

ssu

re.

pci

a

turb

ine

dri

r? f

lw.

No

zzle

Arc

s R

at10

Ove

rall

Rin

ture

Ra

tro

Th

roa

t D

iete

r.

in.

Ou

tle

t F

lon

Rat

e.

lbli

ec

2.

69

Yo1

urr:

ric

Fle

w q

dte,

~

P'I

27

1.4

WS

H. f

t I7

75

Suctlon

fpe

cif

vc

Spe

ed.

(Rr!':

;

5~

!)

"~

/~

f~

)'

~~

wa

Sp

ed

. rcm

10

0.&

?0

Cha

mbe

r 2

:aw

ter.

In.

Ibz

zle

Ex

it 0

ir~

tc.r

. in

.

Co

ola

nt

Jack

et

LH

2 F

led

Qa

te.

15

,'s

~

bo

lrn

t ln

let

Te

a:w

ratu

re.

'R

too

lan

t E

at+

T-r

atur

e.

'R

Cw

lmt

Jack

et

:P. p

ri('

; D

l sc

brg

e P

ress

ure

. p

sia

33

90

Ma

d R

ise

. ft

10

9.70

0 k&

er

of

Icd

ge

s 4

Sw

cif

ic

Spe

ed (

Nr)

. (R

P~

J

:GR

T)"

~/(

FT

J~

/~

717

Inle

cto

r rd

s F

lou

Ra

ter.

lS

/se

c

0,'/H

2 F

ue

l-R

:ch

0 !P

Oxi

diz

er-

Ric

h

O~IR

?-I

F u

el-

RIC

~

ha

d C

0e

ff:c

ien

t

1-1

ler

Tip

Spe

ed.

ft/.

?c

lap

ell

er

Tip

O~

rme

ter.

in.

nJ Gm

bin

ed

Gp

pc

r C

ham

ber

end

T

oh

e B

undl

e P

ress

ure

0-O

P.

02

th~

O

x-R

ich

--

2633

1660

110

34.6

25

.)IS

O2/

RP

-I

rffi

cie

nc

y.

'. F

uel -

Ric

h

Wig

ht

ad

En

velo

pe

25

75

bn

bu

sti

ar

Tm

ratu

re. "I

Ml~

ture

l:io

Ox.

CIa

r R

at..

lbtr

ec

4

-.

Fu

el

Flm

Rat

e.

Iblr

u

V1

-

-

1%

En

gin

e U

elp

ht

= 55

7 1

b

0.37

E

ngin

e L

mg

th:

2.37

E

h-m

dib

lc

'coz

zle

fblo

yed

=

95.2

in

. E

xte

nd

ible

lro

zzle

>tr

ued

=

64.2

in

. 6

41

Eq

im l

bz

zle

Lx

rt D

ia.

= 49

.3

!n.

TABL

E X

XI.

- T

RIPR

OPE

LLAN

T EN

GIN

E PR

ESSU

RE S

CHED

ULE

MOD

E 1

T

hru

st

Sp

lit

= 0.

5

Pre

bu

rne

r F

ue

l -R

ich

-

OX-

Ri c

h

Pro

pe

l 1 an

t LO

X P

ress

ure

, at

m

(ps

ia)

-

--

LH2

LOX

lH2

Ma

in P

ump

Dis

cha

rge

AP

Lin

e

Sh

uto

ff V

alv

e

Inle

t

LP S

hu

toff

V

alv

e

Sh

uto

ff V

alv

e O

utl

et

LP

Lin

e

Co

ola

nt

Jack

et

Inle

t

L?

Co

ola

nt

Jack

et

Co

ola

nt

Jack

et

Ou

tle

t

cP

Lin

e

f b

urn

er

Co

ntr

ol

Inle

t

Ar

Co

ntr

ol

Pre

bu

rne

r In

let

AP P

reb

urn

er

Tu

rbin

e

In1

et

AP

Tu

rbin

e (

To

tal

to S

tati

c)

Che

ck V

alv

e I

nle

t

AP C

heck

Va

lve

Ma

in I

nje

cto

r In

let

LP

Inje

cto

r

Cha

mbe

r P

ress

ure

Fuel -R

ich

LOX

RP-

1 -

Va

cu

a T

hru

st.

M

Ylc

<an

Sp

cd

fic

In

pu

lse

. su

To

tal

Fl

a R

ate

. k

g/s

w

Out

ral!

W

rtu

re

'tti

o

Fra

ct~

on

0

4

LH

7 t5

Tot

dl

Fu

el

Flo

*

'ir,?

er.

F!o

- ?

ate

, C

~fs

cc

Wy!lm

gen

flw

Rate

. k

gls

ec

Pp

-1

Flo

w b

te.

Cg/s

ec

TABL

E XX

I I.

- TRIPROPELLANT ENGINE

OPERATING SPECIF

ICAT

IONS

Mod

e 2

Th

rust

Sp

lit

= 0.5

S.I. UNITS

Th

rus

t C

ha

er

Va

cum

%ru

st.

W

'Iacu

m

Sw

cif

ic

lap

uls

e,

se

t

Cha

nber

p

rsrs

ure

. a

t3

fbz

rle

Are

a R

ati

o

%e

ra1

1

Pir

turc

kt

io

Cn

de

r D

iam

ete

*.

in.

bz

zle

Ex

it D

ian

ete

r.

in.

Co

ola

nt

Jack

et

LH,

Fl

h ;(

ate

, kg

/rec

rbol

ant

:qle

t T

mra

ture

. 'Y

Co

ola

nt

Ex

it T

mer

d:u

re.

"Y

Co

ola

nt

Ja

ck

et cP.

am

Inju

tnr

6d

S F

lOU

Rat

e;.

kg

js.~

0?/1!*

F

ue

l -R

ich

02

/H2

Orf

dfz

er-

Ric

h

OZ

/PP

-1

Fu

el

Ric

h

Yre

bu

rne

rr

C-r

Pre

5lu

re.

ata

Ca

bl~

~tt

or.

T

em

pera

ture

. '1

:

Iha

ture

Ra

tio

Ox

Flo

* Ltc

. kg

/scc

Fu

el

Flw

Pdte.

Cg/

sec

h:f

!:?r h

02/H

2 O

x-R

ich

Tu

rbf n

es

llle

r P

ress

ure

, a

m

Inle

t T

mp

era

ture

, "I

r5ar

F

loa

Pa

re,

L-gf

se-.

Gas

Pro

pc

rtle

5

f.,' .c

.-

-. L.

,

. c ed

:

at

C3*

:t+

73?

Fro

sii-

e,

c5

1/q

-r

.. P

at73

~f

Sy

ec

~fi

c H

eat:

;haf

t ~

crr

ep

we

r'l'

. -#

a

Eff

tclm

cy

. :

Pre

rsu

re b

tr

o 'T

otal

to

:ta

?ic

j

LOX

Turb

opia

p

86.9

3

922

7.5

)

jTj-

~Tnc

lude

TTi;

(rr~

epcw

er p

en

alt

i fo

r tm

r? 9

~

hy

dra

dtf

c tu

rtth

t d

riv

e f

la.

b~

n

Pw

ps

Ou

tle

t F

low

b

te,

tq/s

ec

V~

lme

tric

Flo

r R

ate

, r3

/se

c

t4P:

r. P

Su

ctl

cn

Sx

cif

ic Soted

. (~

4;:

r.~

/se

r.)/

(1~

j~"

Sp

eed

, -p

0:s

ctrs

rgr

Pre

ssu

re,

rta

Head

Pis

e,

n

We

r of

S

taq

es

Sp

eci

f:c

Spe

ed o(%). !R

~)!

ca

~/s

ec

)/(n

)~'~

Hea

d b

eff

fcim

t

lmp

el l

er

Tip

Spe

ed,

n/s

ec

Imp

ell

er

Tip

OiM

ete

r,

m

Eff

icie

nc

y.

Z

LOX !I!%

!

Vac

uum

Th

rust

. Ib

VJC

UJ~

Sy

ec

~fi

c 1~.~~ulse,

se:

Tot

a:

Fls

w R

a:e.

lb's

cc

Ou

era

ll U

irtu

re R

aric

Fra

c?to

n o

f LH

2 to

To:

.l F

ue

l F

low

Oxy

gen

Flo

d P

ate.

1S

i>e:

Hyd

roge

n F

low

Rat

e. 1t:sec

RP

-1

Flo

w R

dte.

I:,

'sec

Vac

sur.

Th

rust

. It

Vdc

s?r.l

Sp

rci f

ic Ir.;,l

se,

5;1c

Ch3

-9-r

P

ress

ure

. cr

:?

No

zzle

A-e

a R

ati

o

Wd

era

ll N

v~

turr

Rat

;o

Th

roa

t O

iare

ter,

in

.

Cha

vber

Oia

mte

-.

in.

N02

zIe

Exl

: O

imte

r.

~n

Co

ola

nt

Jack

et

LW,

Flc

- R

ate.

Ib

/se

c

Co

ola

nt

Inle

t ?

e~

.ce

~a

t,-e

, '?

Co

ola

nt

ix't

T

mp

era

ture

. OR

Co

ola

nt

Jack

et

!P,

ps

i

Inje

cto

r G

as

Flo

w R

ates

. Ib

/se

c

O2/

H2

Fu

el-

nic

h

Oz/

H

Oxi

diz

er-

Rfc

'.

o~

/R~

-I

Fu

el-

Ric

h

Pre

bu

rne

rs

Cha

mbe

r P

ress

ure

, p

sra

tarb

us

tio

n T

m?

era

ture

. 'R

Mix

ture

Ra

tro

Ox

Flw

Rat

e.

Ib/s

ec

Fu

el

Flc

w R

ate.

Ib

/se

c

TABL

E XX

II (

con

t.)

ENGLISH

UNIT

S

"2"'

~

O2

"'z

Fu

tl-R

ich

O

x-R

ich

Turb

ines

Tn

let

Pre

ssu

re,

psi

a

Inle

t T

tw~

pe

ratu

re. O

R

Gas

Flo

* P

ate.

Ib

/%e

c

Gas

Pro

pe

r'ie

s

Cp.

S

pe

~if

ic ''c

at

e? C

onst

ar.t

P

ress

ure

B

tull

b "R

7.

Ra

tio

of

:pe

cifi

c ti

ed:$

Sh

af?

Hor

sepo

wer

('

Eff

-cie

ncf

. X

Pre

ssu

re R

ati

o (

rotd

l to

.:t

ati

c)

LOX

Turb

opup

1264

1663

17.1

55

~c

lud

G-

3h

s-

:ep

ow

er

p

eid

lty

*o

r b

oo

st O

~JFD

htd

rdu

lic

tu*

b:ne

d

riv

e f

lw.

Ou

tle

t ll

cw

Rnt

e,

lbls

ec

Vo1

une:

rtc

Flo

w R

.~ta

, i1,m

hPS

ti.

ft

Su

ctio

o S

pe

ciri

c S

pecd

. (P

PU

!(G

:Y~

~/~

/(~

T)~

!~

5~

c-,

I. r

p

Dis

ch

dr~

e Pre

sstir

e.

?%

id

Hea

d R

ise,

ft

Nun

ber

of

Sta

ges

Sp

ec

ific

Spe

ed

(idS

).

!RP

I!)(C

~:I)~

'?/(F

T)~/

'

Hea

d C

oe

ffic

ien

t

Imp

ell

er

Tip

Spe

ed,

ft/%

ec

Imp

ell

er

Tip

Oia

ncle

l-,

in.

Eff

icie

ncy

. lr

L"?

LOX

&?I!

. . . - I.. . . ,' - - . , .:-

3 ,..&-... ...- *-.-__C1 -"?"---*w~ - . . . i

V, 8, Engine System Evaluation (cont.)

Table XXIlI. Thi table shows tha t the oxygen-rich preburner oxygen in jec- t i o n pressure drop decreases from a design po in t 15% o f the upstream pressure t o 8.4%. This problem could be solved by red i s t r i bu t i ng pressure drop between control valve and the in jebtor . However, t h i s so lut ion would resu l t i n higher Mode 1 pump discharge pressure requirements and heavier turbomachinery.

Baseline engine weight and envelope data are also shown on Table XX. The weights were obtained by scal ing o f h i s to r i ca l component data w i th thrust, pressure, surface area, dimensions, etc. Detailed component weight breakdowns and dimensions are presented i n the next section under Task I V .

Based upon the cycle analyses and a comparison o f the Mode 1 and 2 pressure schedules, the fol lowing control requirement conclusions were reached. Preburner controls i n the 02/H2 fue l - r i ch preburner should be simple o r i f i c e s t o minimize pressure drop requirements. Control valves are required i n the fuel and ox id izer feed l i nes f o r the 02/H2 oxidizer- r i c h preburner t o properly d i s t r i bu te f low and balance the engine i n Mode 2. Ei ther a control valve o r an o r i f i c e can be used i n the ox id izer l i n e of the 02/RP-1 fue l - r i ch preburner. A hot-gas check valve i s required between the RP-1 TPA and n ~ i n i n jec to r t o p roh ib i t main chamber combustion products from backing through the turbopump shaf t and i n t o the suction l i n e when the RP-1 pump i s inact ive (Mode 2). Main propel lant shutoff valves are placed i n the l i nes j u s t downstream o f the turbopumps. These control requirements have been i den t i f i ed on Figures 51 and 52.

The e f fec t o f thrust s p l i t upon the engine cycle power balance was also investigated. The resul ts o f these analyses are shown on Figures 57, 58 and 59.

Figure 57 shows the e f fec t o f th rus t s p l i t upon the hydrogen pump discharge pressure requirements. Hydrogen pump discharge pressure requirements a t th rus t s p l i t s o f 0.4 and 0.5 are almost equal. Fuel pump horsepower requirements a t a th rus t s p l i t of 0.4 are higher but the fuel preburner f low r a t e i s also higher. This ac tua l ly re ru l t s i n a reduced hydrogen pump turbine vessure r a t i o a t a th rus t s p l i t o f 0.4. A s l i g h t l y higher coolant jacket pressure drop requirement a t a thrust s p l i t o f 0.4 resul ts i n the small increase i n pump discharge pressure a t a f i xed chamber pressure. For example, a t a chamber pressure o f 136 atm (2000 psia), the hydrogen pump discharge pressure requirements are 231 and 233 atm (3390 and 3420 psia) a t thrust s p l i t s o f 0.5 and 0.4, respectively. Coolant jacket pressure drops a t 136 atm (2000 psia) chamber pressure are 17.3 and 20 atm (255 and 295 ps i ) a t thrust s p l i t s o f 0.5 and 0.4, respec- t i ve ly .

a . a m - w a a ? T y y w ? y y 0

F . d l & ? u , r . c 7 , * a , , & , N h n - - - A - - e o - w ( U m - m - - . - N O , a m .L- C C C C C e m : :-3hO N C Y Y g - 0

c - C C Y V Y

C h m

- - A - h n C I A - h h C 1 - . . o ? ? 4 u s ~ ; ; ; ~ ; ; m ~ I I ~ c o l n m - ~ - ~ I C C U ~

I l l . - O - O w - w 0 0 ~ - ~ . r u u u O c O 1 ; X -

C U - - - - V

TRIPROPELLANT ENGINE MODE 1, THRUST = 88964N

50 100 150 200 THRUST CHAMBER PRESSURE, ATM

I I I 1 I I 0 (500) (1000) (1500) (2000) (2500)

THRUST CHAMBER PRESSURE, (PSIA)

Figure 57. Ef fect o f Thrust S p l i t Upon Hydrogen Pump Discharge Pressure Requ i remen t s

Figure 58. E f f e c t a f Thrust S p l i t Upon Oxygen Pump Discharge Pressure Requirements

122

(5000)

(4500)

(4000) 5 V) n V

I

W

5 (3500) vl V) W = h

W

: (3000) e I U vl C(

a

5 (2500) n Z W a 2.

:: (2000)

(1 5CO)

(1000)

r

TRI PROPELLANT ENGINE MODE i , THRUST = 88964N (20,000 LB) -

-

-

-

-

-

'

-

0 THRUST CHAMBER PRESSURE, atm

0 50 100 1 50 200 THRUST CHAMBER PRESSURE, atm

1 1 I I I

0 1

(500) (1000) (1500) (2000) (2500) THRUST CHAMBER PRESSURE, (PSIA)

Figure 59. RP-1 Pump Discharge Pressure Requirements for A l l Thrust Spl i t s

V, 0 , i ng ine System Evaluation (cont.)

A t a t h rus t s p l i t of 0.8, the hydrogen f low i s reduced sub- s t a n t i a l l y . The fue l pump tu rb ine pressure r a t i o i s s l i g h t l y l a rge r f o r a given pump discharge pressure because the tu rb ine horsepower t o f l ow r a t e r a t i o increases. The coolant jacke t pressure drop requirenent f o r a f ixed t h rus t chamber pressure i s a1 so much greater. For example, a t a t h rus t chamber pressure of 136 atm (2000 psia), the coolant jacke t pressure drop i s 68 atm (1000 p s i ) a t a t h rus t s p l i t of 0.8. These e f f ec t s r e s u l t i n increased hydrogen pump discharge pressure requirements. However, even a t a t h rus t s p l i t o f 0.8, the cyc le i s no t power balance 1 i m i ted.

Figure 58 shows the e f f ec t o f t h rus t s p l i t upon the ox i d i ze r pump discharge pressure requirements. The e f f e c t i s almost negl i g i b le . The t o t a l ox id ize r f l ow r a t e and ox i d i ze r - r i ch preburner t o t a l f l ow ra tes are almost constant as a func t ion o f t h rus t s p l i t . A t a t h rus t s p l i t of 0.8, the ox i d i ze r f low must be pumped to a pressure high enough t o meet the tu rb ine i n l e t pressure requirements which a re f i xed by the f ue l s ide pressure drops.

Because a l l o f the RP-1 i s combusted i n a f u e l - r i c h preburner t o d r i v e the RP-1 turbopump, the t o t a l preburner f low increases almost d i r e c t l y w i t h the RP-1 f low ra te . Therefore, t h r u s t s p l i t does no t a f f e c t the RP-1 pump discharge pressure requirements. The RP-1 pump discharge pressure data i s shown on Figure 59.

2. Dual -Expander Engine

I n i t i a l power balance analyses were conducted a t the nominal Mode 1 t h rus t l eve l o f 88964N (20,000 l b ) and a t h rus t s p l i t o f 0.5. The e f f e c t o f t h rus t s p l i t upon the power balance was a1 so established. With the discharge pressure requirements and operat ing chamber pressure i den t i f i ed , base1 ine performance, weight, and envelope data were deter- m i ned .

Simp1 i f i e d dual-expander engine cyc le schematics are shown on Figures 60 and 61 fo r Mode 1 and 2 operation, respect ive ly . During Mode 1 operation the preburner ho t gas cont ro l valves spl i t the preburner gas f low ra tes t o the turbznes. I n Mode 2 operation, these preburner hot gas cont ro l valves provide the proper f low ra tes t o the hydrogen and oxygen pump turbines and bypass the f lows prev ious ly used t o d r i v e the RP-1 pump turb ine and Mode 1 oxygen pump turb ine. Hot gas check valves are shown between the Mode 1 TPA turbines and the main i n j e c t o r t o p r o h i b i t main chamber combustion products from backing t hrouqh the turbopump shaft and up the pump suct ion l i n e when these turbopumps are inoperat ive i n Mode 2. Main shu to f f valves are a lso provided i n each pump discharge l i n e .

V, B, Engine System Evaluation (cont.)

Pump e f f i c i enc ies used i n the power balance analyse* ..ere derived as described f o r the t r i p r o p e l l a n t engine i n Section V,B,1. Design po in t turb ine e f f i c i enc ies were estimated as:

LH2 TPA - 80%

LOX TPAs - 70%

RP-1 TPA - 602

The coolant jacket pressure drop and coolant o u t l e t temperature data required i n the power balance analysis was establ ished i n Task 11. This data showed tha t the maximum operating chamber pressure o f the dual - expander engine i s cool ing l i m i ted. However, f o r the parametric power balance analyses, i t was assumed tha t the l i m i t s could be exceeded and the pressure drop and cool ant out1 e t temperature data a t higher th rus t s p l i t s and pressures were estimated from the Task I 1 data. I t was assumed tha t cool ing could be accompl ished w i t h i n the bu lk temperature', 756OK (1360°R), l i m i t and the coolant Mach number o f 0.5 excecded. The values used i n the power balance aniilyses are:

Central Chamber Thrust Pressure, S p l i t atm (ps ia)

Annular Chamber Cool ant Jacket Pressure, Pressure Drop,

atin ( p s i a j atm (ps ia )

Cool ant Out1 e t Temp * , OK (OR)

. . Based upon the above coolant data and tu rb ine i n l e t temperature requirements, the fo l lowing preburner mixture r a t i o s were established t o

= . ob ta in the turb ine d r i ve gas propert ies.

V, B, Engine Systez Evaluation (cont.)

Turbine I n l e t Central Chamber Fuel -Rich Ox-Rich Tempera+llrar.

Thrust Pressure, Preburner Preburner O K ( d ) S p l i t atm (ps ia) - MR MR tue l -Rich Ox-Rich

The power balance analyses resu l t s are displayed i n Figures 62 through 65.

Figure 62 shows the LOXIRP-1 system pump discharge pressure as a funct ion of the cent ra l chamber t h rus t chamber pressure. Because the turbines f o r the pumps are dr iven i n a mode o f operat ion s im i l a r t o a gas generator engine cycle, the pump discharge pressures required are on ly a funct ion 3f the chamber pressLre. Thrust spl i t has no effect.

The hydrogen pump and oxygen pump discharge pressure requi rements f o r the LOX/LH2 system are shown on Figure 63 a t a t h rus t s p l i t of 0.5. The hydrogen pump discharge pressure i s much greater than the oxygen pump because o f the AP incurred i n the coolant jacket. Because the pumps f o r the LGX/LH2 system are dr iven i n a staged combustion cyc le mode o f operation, the discharge pressures are a funct ion o f the tu rb ine pressure r a t i os . The analyses showed t h a t the oxygen turbopump tu rb ine pressure r a t i o was greater than the hydrogen turbopump turb ine pressure r a t i o . Therefore, the oxygen-rich preburner c i r c u i t s govern the poweta balance. This a lsc means t h a t the preburner cont ro ls should be placed i n the fue l - r i c h prebur3cr because addi t iona l pressure drop i s ava i lab le . Simple balancing o r i f i c e s are shown i n these c i r c u i t s on the schematics. However, the excess pressure ava i lab le i s enough to accommodate a 1 i q u i d oxygen cont ro l valve and almost enouqh f o r a hydrogen gas cont ro l valve.

Figure 63 also shows t ha t the discharge pressure requirements f o r the engine are not unreasonable and the cyc le i s not power balance liri ted up t o a chamber pressure o f 68 atm (1000 ps ia) a t a t h rus t s p l i t o f 0.5.

C

i = 88964N (20,00C LB) ALL THRUST SPLITS

LOX AND RP-1 PUMPS

1 I I 5 0 1 00 1

LOX/RP-1 THRUST CHAMBER PRESSURE, ATM

t 1 I I

( 500 ) ( 1 000) (1 500) (2000) LOX/RP-1 THRUST CHAMBER PRESSURE, (PSIA)

Figure 62. Pump Discharge Pressure Requirements for Dusl -Expander Engine LOXIRP-1 System

F = 88964N (20,000 LB) HYDROGEN PUMP

LOX/LH2 THRUST CHAMBER PRESSURE. ATM

I I 1 I I I I

(200) (400) (600) (800) (1000) (1200) (1400) LOX/LH2 THRUST CHAMBER PRESSURE, (PSIA)

Figure 63. Pump Discharge Pressure Requirements f o r Dual-Expander Engine LOXILH2 System

THRUST SPLIT

L I I 1 25 50 75

LOX/LH2 CHAMBER PRESSURE, ATM

(400) (600) ( 800 (1 000) ( 1 200) LOX/LH2 CHAMBER PRESSURE, (PSIA)

Figure 64. E f f e c t o f Thrust S p l i t Upon Hydrogen Pump Discharge Pressure, Dual -Expander Engine

THRUST SPLIT

2 5 50 75 1 00 LOX/LH2 CHAMBER PRESSURE, ATM

\ I I I I I 1 (230) (400) (600) (800) (1000) (1200) (1400)

LOX/LH2 CHAMBER PRESSURE, (PSIA)

Figure 65. E f f e c t o f Thrust S p l i t Upon LOX/LH2 Oxygen Pump Discharge Pressure, Dual-Expander Engine

V, 8, Engine System Evaluation (cont.)

The e f fec t o f thrust s p l i t upon the hydrogen pump and LOX/LH2 system oxygen pump discharge pressure requirements are shown on Figures 64 and 65, respectively. The required discharge pressures increase w i th . increasing th rus t s p l i t because the to ta l preburner f low ra te used t o d r ive a l l four pumping systems decreases as th rus t spl i t increases ( i .e., only the LOXJLH2 system flows are precombusted and used as turbine d r i ve gases). The cycle i s not power balance l im i ted bu t i s very marginal a t a i h rus t s p l i t o f 0.8 and a LOX/LHz system chamber pressure o f 68 atm (1000 psia). A turbine pressure r a t i o i n excess o f 2.5 i s required for the oxygen turbopup which i s high for a staqed combustion cycle.

Because the engine i s cooling 1 i m i ted, the maximum operating thrust chamber pressures selected f o r the LOXIRP-1 central chamber and LOXILH2 annular chamber are 74.8 and 37.4 a tm (1 100 and 550 psia), respec- t i v e l y a t the baseline th rus t s p l i t o f 0.5. The basel ine dual-expander engine and component pre l iminary opera t i ng specif icat ions f o r these maximum chamber pressures are shown on Table X X I V . During Mode 2 operation, the LOX/RP-1 system turbopumps are shutdown. The preburner and LOX/LH2 pump and turbirie operating parameters i n Mode 2 are the same as i n Made 1. The preburner f low rates used t o d r ive the LOXIRP-1 system pumps bypass the turbines and are delivered t o the annular thrust chamber. Only some of the thrust chamber parameters change i n Mode 2 due t o the area r a t i o amp1 i f i ca t i on and non-operating central chamber as shown on Table XXV.

The pressure schedule f o r the base1 ine dual -expander engine which resulted from the study system pressure loss guidelines and the cycle power balance analysis i s shown on Table X X V I . From t h i s table i t can be noted tha t the power balance i s governed by the LOX TPAs turbine pressure rat ios. Therefore, the preburner f low controls are shown i n the fue l - r i ch preburner c i r cu i t s . The AP across these controls i s 7.4% of the upstream pressure.

The pump discharge pressure requirements determined through the power balance analyses were incorporated i n the engine parametric data model so tha t weight effects were accounted for w i th changing discharge pressures. Baseline engine weight, envelope and performance data are also shown on Table X X I V f o r t b i s engine concept.

3. Plus Cluster Engine

Power balance analyses were conducted a: ,< l weight, envelope, and performance data were also establ ished a t the nominal Mode 1 thrust level of 88964N (20,000 l b ) and a th rus t s p l i t o f 0.5 f o r the mixed-mode plug cluster concept.

TABLE XXIV. - BASELINE DUAL-EXPANDER ENGINE OPERATING SPECIFICATIONS, MODE 1 . . --.-

nMust split - 0.5 1.1. U(ITS

v- m u s t . I v- SpICfflc Iqrlrc, uc Total Flab b W , k g %

.3xtmm Ratio

Oa,p fla Raw. kg/* b - 1 flor R lb . kg=

F l a bte. kg/%

Thrust CWcr v- fkurt. n v- S#ciT lc I q u l r c . wc

Pressurw. rb lDzzle *CCI Ratio

mt m. m2 t o o l m t Jacket LH2 F l a Rate. t g / u c

coolant I n l e t T q r r c u n . 1 Coolant Ex i t 1-rum. OK

tool-t J W U t 3. r b l n j c c t n F l w ktn. tp/scc

onm IP-1 O#l$ Fw1-Rich 6.1

0#H2 ox-Rich 61s

I n l e t Rcssun. r b 42.5

l a l e t Tap r r tu re . 'K 1033

fir Fhm Ute, kglrcc 1 .Q

C s PrO#rt iCI Cp. S p ~ l f t c krt rt constant pressure. Ca1/qoK 2.60

7 . Ratio of specific heats 1.363

Shrft m r r c O a r ( l ) . .IP 80.94

Efficimcy, X 60 Pmssure Ratto (Total to Static) 1.031

7T-l Includes 3 1 Horsecam pmal ty for b w s t purp drtve flo*.

LOX 'LH2 LCI

J!!ES- Plrp R l n Rnm

Outlet F lo* I r t e , t g l s u

Vo luc t r i c F I W Rate. d l s e c

NPSH. m Suction ~ p c t ~ ~ c SW. I R P M I ( ~ ~ / S ~ I ~ / ~ / ( ~ ) ~ / ~

Sprcd. RPX Ditchrrqe Pressure. rln

Ue8d Rise. m mnbcr o f Scaqes fpcct f ic sw ( ~ ~ 1 . ( ~ ~ l l ) ( n ~ / s w , ~ / ~ / ( m ) ~ / ~

Head Coefficient

lntpelter Tip Sped. sJSu

lnpc l lcr Tlp D i r r t e r , n

Efflcicncy. :

Uelpht an6 I n v t l o g

Enqtne Ueight 0 249.5 kg

tnqine Length 229.1 cm

Enqinr F l i t Dtr. - 148.6 cm

TABLE X X I V (cont. )

V * C W Thrust. I 0

lp+cifl~ tnouln. In h t r l $ l a h t e . I W s u

l l a t u n LC10 o v ~ n rlw *h. IVSCC

a - 1 f lw Ute . I b l r u

Thrust ChWr

lkCw T h s t . I 0

rr~vpl *lfi~ I ~ l s c . s u

e M c r Pressure. prlr

m u l e rm WIO

n m a t A m , I".? U o l ~ t J b c l ~ t LHt f l a h t r . Iblsec

Coolant I n l e t T w r r in. ' a Q o l u t hit Tng l r r t un . *I

C a l m t Jacket A?. psi* t*mr nam ktrs. l b ' su

Qvrc. a-I 0& l w l - l l c h Us 0#12 &-Rich U s

&E!Ei Qrkr Pr'rsrun. p t r

ObYst1.l) Tap.. *n NfltrW * t l 0

O.. F l w Ltr. I b l w c

h l flw kh. Iblsec

blrt Pmsurr. p r l r Imtet T w p r r t u r r . *I

C a flw Rate. lb1,rc

I s h v r r t l e s Cp. I p u l f l c k r t r l comtrnt prcsrun I tJ lb . 'R ,. LCIO o f spW!rcc hr.

~ . f ; tierr*-r")

f f f l c l m y , x C m ; a b t l o (Total t o Str t lc ;

~ ~ ~ ~ ~ f - ~ r s t p r n r pcnrlty l o r boost lwv dr l v r tla.

h d w of Strgrs

b l f t ~ S W ~ (Rs), ~ R ~ ) I G ~ M ) ' ' ~ / [ ~ ~ ) ' ' ' k r d Gwf f~c l rnc

I# l ler TIP I~ce.9. f t l l r c I#llrr 1tp Dl r r r ter . In .

Ifflcl*ncy. 1

l r) lR8 V e l ~ h t 5% I b

I q t m L n g t h 09.8 In.

II(IM kltlr 1111 D i r . 58.5 In.

TABLE XXV . - BASELINE DUAL-EXPANDER ENGINE OPERATING SPEC I FICATIONS , MODE 2

Thrust S p l i t = 0.5

Engine

Vacuum Thrust, N (1 b)

Vacuum Specif ic Impul se, sec

Total Flow Rate, kg/sec (lb/sec)

Mixture Ratio

Oxygen Flow Rate, kg/sec ( 1 b/sec )

RP-1 Flow Rate, kg/sec ( I b/sec)

Hydrogen Flow Rate, kg/sec (1 b/sec)

Thrust Chamber

Vacuum Thrust, N ( l b )

Vacuum Specif ic Impul se, sec

Chamber Pressure, atm (psia)

Nozzle Area Ratio 2 Throat Area, cm2 ( in . )

Coolant Jacket LH2 Flow Rate, kg/sec (lb/sec)

Coolant I n l e t Temperature, O K (OR)

Coolant E x i t Temperature, O K (OR)

Coolant Jacket AP, atm (psia)

In jec tor Flow Rates, kg/sec (1 b-sec)

Oxygen

RP-1

02/H2 Fuel-Rich Gas

02/H2 Ox-Rich Gas

TABL

E X

XV

I. -

BA

SE

LIN

E D

UAL-

EXPA

NDER

EN

GIN

E PR

ESSU

RE

SCHE

DULE

, MO

DE 1

T

hru

st S

D~

it =

0.5

Pre

ssur

e,

atm

Mai

n Pu

mp

Dis

cha

rge

cP L

ine

Sh

uto

ff V

alv

e

Inle

t

LP

Sh

uto

ff V

alv

e

Sh

uto

ff

Vtl

ve

Ou

tle

t

AP

Lin

e

Coo

l an

t Ja

cke

t In

1 e

t

LP

Co

ola

nt

Jack

et

Co

ola

nt

Jack

et

Out

1 et

cP L

ine

Pre

bu

rne

r C

on

tro

l In

let

cP C

on

tro

l

Pr e

bu

rne

r In

let

AP P

reb

urn

er

Hot

Gas

C

on

tro

l V

3lve

In

let

AP H

ot G

as

Co

ntr

ol

Va

lve

Tu

rbin

e I

nle

t

AP T

urb

ine

Che

ck

Va

lve

In

let

AP

Che

ck

Va

lve

M

ain

Inje

cto

r In

let

oP

Inje

cto

r

Cha

mbe

r P

ress

ure

I F

low

Ci r

cu

i t

I I

I I

0x

4 ch

I

TABL

E X

XV

I (c

on

t.)

EN

GLI

SH

UN

ITS

Pre

ssur

e,

ps

ia

Mai

n Pu

mp

Dis

char

ge

:P L

ine

Sh

uto

ff V

alve

In

let

LP S

hu

toff

Val

ve

Sh

uto

ff V

alve

Ou

tle

t

AP L

ine

Coo

lant

Ja

cke

t In

let

AP

Coo

l an

t Ja

cke

t

Coo

lant

Ja

cke

t O

utl

et

AP L

ine

Pre

burn

er C

on

tro

l In

1 e

t

hP

Co

ntr

ol

Pre

burn

er I

n1

et

AP P

rebu

rner

Hot

Gas

C

on

tro

l V

alve

In

let

AP

Hot

Gas

C

on

tro

l V

alve

Tu

rbin

e

Inle

t

AP T

urb

ine

Che

ck V

alve

In

let

AP C

heck

Val

ve

Mai

n In

jec

tor

Inle

t

AP

Inje

cto

r

Cha

mbe

r P

ress

ure

Ce

ntr

al

Th

rust

C

ham

ber

LOX

1390

40

1350

14

1336

40

- - - - - - - - - - - -

- - - - - - - - - -

- - - -

- - 1296

196 11

00

Fue

l -R

ich

're

burn

er

LH2

Pum

p

RP-1

1390

40

1350

14

1336

40

- - - - - - - - -- - - - - -

- - --

- - - - - - - -

1296

196

Tu

rbin

e

LOX

930 2 0

910 9

901 20

- -

- -

- -

- - 881 65

816

122

Flo

w

Fuel

-R

ich

Pre

burn

er

RP-

1 Pu

mp

LH2

1115

2 0

1095

11

1054

20

1064

210

854 40

814 60

754 60

Tu

rbi

LOX 93

0 20

910 9

901 20

--

--

-- -- 881 6 5

816

122

- - - - 694 96

- - - - 5 98 48

550

ne

LH2

1115

2 0

1095

11

1084

20

1064

210

854 40

814 60

754

60 Cir

cu

it

Ox-

Ri c

h

Pre

burn

er

LOX

Pum

p

694 69

625 2 1

604 6

598 48

550

Tu

rbin

e

LOX 93

0

2 0

910 9

901 2 0

--

--

--

--

--

--

881

132

Ox-

Ric

h P

rebu

rner

LO

X Pu

mp

Tu

rbin

e

LH2

1115

2 0

1095

11

1084

2 0

1064

210

854 40

- -

- -

814 65

LOX/

RP-

1

LOX 93

0 20

910 9

901 2 0

--

--

-- -- - - - -

881

132

- - - - 749

151

-- - - 598 48

550

Sys

tem

LH2

11 15

20

1095

11

1084

2 0

1064

21 0

854 40

-- --

81 4 65

749 75

674 70

604 6

5 98 48

550


S imp l i f i ed plug c l u s t e r engine cyc le schematics a re shown on Figures 66 and 67 fo r Mode 1 and 2 operation, respect ive ly . The p lug c l us te r consists of f i ve 02/H2 modules and f i v e 02/RP-1 modules. The 02/H2 modules are fed by a s ing le turbopump assembly which employs an expander d r i v e cycle. Hydrogen i s f i r s t used t o cool the p lug base c losure before coo l ing the 021H2 modules. The heated hydrogen i s then used t o d r i ve the 02 and H pumps. A small po r t ion of the hydrogen, about 0.2% o f :he i o t a1 engine f f ow, i s used as base bleed and the r e s t i s combusted w i t h the 1 i q u i d oxygen. The 021RP-1 modules are a lso fed by a s i ng le turbopump assembly which uses a gas generator d r i v e cycle. The f u e l - r i c h tu rb ine exhaust products can be e i t h e r dumped down the p lug o r ou t a 5:l tu rb ine exhaust nozzle. An i n d i ~ i d ~ a l tu rb ine exhaust nozzle r e s u l t s i n less hot gas manifolding because the "plug dump" must be evenly d i s t r i b u t e d over a l a rge circumference. The i ndiv idual tu rb ine exhaust nozzle was assumed i n t h i s analysis. A zero length p lug nozzle i s used and the module area r a t i o s are establ ished as a func t ion o f ove ra l l area r a t i o f o r 10 touching modules. The zero length p lug was selected on the basis o f r esu l t s from the Unconventional Nozzle Tradeoff Study (Ref. 3). The ove ra l l p lug c l us te r area r a t i o i s shown as a func t ion o f the module area r a t i o below.

No. o f Module Overal l Mode 1 Touchi nq Modules Area Ratio- C1 us te r Area Rat io

For the h igh module area ra t i os , the performance con t r ibu t ion from adding a truncated i sen t rop ic p lug i s small and the add i t i on of the plug weight i s no t warranted. A p lug base c lcsure i s added t o obta in the base pressure benef i ts .

As discussed i n Section I V , Cooling Evaluation, a chamber pressure o f 20.4 atm (300 ps ia) was selected f o r t h i s concept because of the problems associated w i t h coo l ing the 02/RP-1 module.

The coolant jacke t pressure drop and coolant o u t l e t temperature data required f o r the power balance analysis are summarized below:

HYDR

OG

EN

GG

G

AS G

ENER

ATO

R T

/7_

rr

OXY

GEN

H

IG

H

DE

NS

ITY

FU

EL (

vtl

)

GB

GEAR

BOX

CO

nBU

SflO

N P

RODU

CXS'

P

PUM

P T

TURB

INE

Fig

ure

66.

Mod

e 1

Plu

g C

lust

er E

ngin

e S

chem

atic

mon

roost

SHUT

OFF

VALV

E

HYI

RC

GEN

GG

GA

S G

ENER

ATO

R 2

~i

Z

ox

~c

~w

GB

GE

AR B

OX

;= ' CO

MU

Si I O

N PRODU~W'-

P PU

MP

T TU

RBIN

E TC

TH

RUST

CHA

UBER

Fig

ure

67.

M

ode

2 Pl

ug Cluster E

ngin

e Sc

hema

tic

t

V, 8, Engine System Evaluat ion (cont. )

Chamber Total Coolant Coolant O u t l e t Pressure, Pressure Drop, Temp. ,

atm p s i a ) Module atm (ps ia) O K (OR)

20.4 (300) O2IH2 0.34 (5.0) 359 (647)

20.4 (300) 02/ RP- 1 40.8 (600) 899 (1456)

The hydrogen pressure drop and o u t l e t temperature inc lude the e f f e c t o f coo l ing the p lug base.

Based upon a review of RL-10 data, the anzlyses conducted f o r the Unconventional Nozzle Tradeoff Study (Ref. 3) and the t r i p r o p e l l a n t and dual -expander engine analyses performed f o r t h i s contract , the fo l l ow ing turbomachinery e f f i c ienc ies were used i n the power balance analyses :

E f f i c i e n c y

Oxygen Pump 63% Hydrogen Pump 6 0% Turbine 72%

Oxygen Pump RP-1 Pump Turbine

Pump discharge pressure requirements f o r a module t h r u s t chamber pressure o f 20.4 atm (300 ps ia ) are shown on Tables X X V I I and X X V I I I f o r the gas generator and expander cycles, respect ive ly . lhese tab les a lso show the pressure drop data f o r each o f the system components.

Prel iminary engine operat ing spec i f i ca t ions f o r the estab l ished pressure requirements are shown on Table X X I X f o r Rode 1 operation. During Mode 2 operat ion the LOX/RP-1 modules are shutdown and the on ly major e f f e c t i s t h a t the gap between modules goes t o one (1) w i t h an at tendant overa l l p lug c l u s t e r area r a t i o amp l i f i ca t ion from 358:l t o 715:l. The O2/H2 component operat ing condi t ions remain about the same as i n Mode 1.

Table X X I X a lso shows t h a t f o r a s i n g l e stage RP-1 pump, the operat ing speed i s 90,000 RPM which i s bear ing DN l i m i t e d . This speed i s a lso s i g n i f i c a n t l y higher than the oxygen pump speed. If a s i n g l e shaf t , s ing le turb ine d r i v e i s desired f o r the LOX and RP-: pumps, as shown on the cyc le schematic, the RP-1 pump speed must be reduced. A possible operat ing

TABLE X X V I I . - PLUG CLUSTER 02/RP-I GAS GENERATOR CYCLE

PRESSURE SCHEDULE

5 . I. UNITS

Module Thrust Chamber Flows

Gas Generator Flows

Pressure, atm

Main Pump Discharge

AP L i n e

Shutoff Valve I n l e t

AP Shutoff Valve

Shuto f f Valve O u t l e t

AP L i n e

Coolant Jacket I n l e t

AP Coolant Jacket

Hain I n j e c t o r I n l e t

AP I n j e c t o r

Chamber Pressure

Prope I , ~n t Oxygen '-?-I '

29. r

RP-1

70.9

2.7

68.2

3.4

64.8

42.1

22.7

Pressure, a t m

Main Pump Discharge AP L i n e

G.G. Valve I n l e t

AP G.G. Valve

G . G . I n j e c t o r I n l e t

AP G.G. I n j e c t o r

70.9

Oxygen

29.7

2.7

??.O 0.3

26.7

4.0

Turbine I n l e t i 22.7 J

2.7 1 2.7

27.0

0.3

26.7

2.7 - - --

24.0

3.6

20.4

68.2

0.7

57.5

2.7 64.8

40.8

24.0

3.6

20.4

TABLE X X V I I icont.)

ENGLISH UNITS

Module Thrust Chanber Flows

Gas Generator Flows

Pressure, psia Mairt Punp Discharge

AP Line Shutoff Valve I n l e t

AC Shutoff Valve Shutoff Valve Outlet

AP Line Coolant Jacket I n l e t

AP Coolant Jacket

Main In jec to r I n l e t

AP In jector

Chanber Pressure

4

Propel l an t

Pressure, ps i a Main Pump Discharge AP Line

G.G. Valve I n l e t

AP G.G. Valve

G.G. In jec tor I n l e t

bP G.G. I n jec to r

Turbine I n l e t

O ~ Y gen

437

40 397

4 393 40 - -

353

5 3

300

- 1043

40

1003 10

993

40

953

600

353 5 3

300

Oxygen 437

40

397

4 393

59

334

RP-1

1043

40

1003 50

953

61 9

334 ' I

TABLE X X V I I I. - PLUG CLUSTER 02/H2 EXPANDER CYCLE PRESSURE SCHEDULE

S.I. UNITS

Pressure, atm

Main Pump Discharge

AP Line Shutoff Valve I n l e t

AP Shutoff Valve

Shutoff Valve Out le t

AP Line


AP Coolant Jacket

Coolant Jacket Out le t

AP Line

Turbine I n l e t AP Turbine Main I n j e c t o r I n l e t

AP In jec tor

Chamber Pressure

. 4

Propel Hydrogen

30.5

? .4 29.1

0.3

28.8

1.4

27.4

0.3

27.1

2.7

24.4

2.2 22.2

1.8

20.4

1 an t Onygen

29.7

2.7 27.0

0.3

26.7

2.7 * - - - - - -- -- - -

24.0

3.6

20.4 -

TABLE X X V I I I (cont . )

ENGLISH UNITS

*

Pressure, psia

Main Pump Discharge

AP Line

Shutoff Valve I n l e t

AP Shutoff Valve

Shutoff Valve Out le t

AP Line


AP Coolant Jacket

Coolant Jacket Out let

AP Line

Turbine I n l e t AP Turbine

Yain I n j e c t o r I r l l e t

AP I n j e c t o r

Chamber Pressure*

2

HY drown

448 20

428 4

424 20

404 5

399

40 359

33 326

26

300

Propel lant @wW*

437 40

397 4

393 40 - - - - - -

353 5 3

300 A

TABLE XXIX. - PLUG CLUSTER ENGINE PRELIMINARY OPERATING SPECIFICATIONS MODE 1

Thrust S p l i t = 0.5

Vacum Thrust, N Total F l a L t e . kglsec

Rixture h t l o

O~ygne F l w L t e . kg/sU

RP-I Flow Rate. kg/s%

Hydrogen F l w Rate. kg/stc

Ibbu)cr

Yacum Thrust. W

Chwber Pressure. r an

Ibzz le Area b t f c

T n m t A m . cr2 T h m t O i m t e r . a b z z l c Ex i t Area, cm2

Nozzle Ex i t O i l l r t e r . an

Plug Cluster

Base Thrust. N

l&m&er of W u l e s

Plug Cluster Area Ratio

Total Throat Ana, c12

Total Ex i t ~rea(" . cm2

Plug Cluster D i o r t e r . an

QP

Tncludes b r z .

02/RP-I Module 0$n2 Module

RP- 1 LOX LON

Outlet F l ~ u Rate. kgfsec

Volumetric Flow Rate. m3/sec

NPSH. m

Suctlon Speciflc Speed ( ~ ~ ~ l ) i m ~ i s e c ) ' ~ ~ l ( m ) ~ ' ~ Speed. RPn Discharge Pressure. atm

Head Rise. m Nunber o f Stages

Specific Speed (NsJ. ( ~ ~ ~ ) ( r n ~ / s e c ) ~ / ' ~ ( r n ) ~ / ~

Head Cwf f l c i en t

Impeller Tip (peed. m/sec

Impeller Tip I iamtter. cn!

Horsepower. * . P

Efficiency. :

TABLE X X I X (cont. )

9 s Generator

RP-I l n l e t Temp.. OK

Chrrnbcr Pressure, atm

Cmbust ion Tmp.. OK

Mtxture Ra t io

Ox. f l o r Rate. kg!ser

RP-1 Flow Rate. kulsec

Total Flow Rate. k g ~ s z c

Turbines

I n l e t Pressure. abn

l n l e t Temperature. '1;

Gas F l o r U t e . kgisec

Gas Propert ies

RP-I LOX Turbo=. ~urpE!9!!!!%?

C . Speci f ic Heat a t Constant Pressure. 0.54 0.64 C~PII~=K

,. Rat io of Speci f ic Heats

Shaft ). mHP

Efficiency. %

Pressure 3 d t i o (To:al To S t a t i c )

: I m u d z T r horsepower penal ty fo r boost pump d r i v e f low.

Turbine Exhaust Performance

Turbine E x i t Pressure. atm

Turbine E ~ i t To td l Temp.. "K

Gas l b l e c u l a r i le ight

Ra t io of Spccif i c Heats

Charac te r i s t i c Exhaust Ve loc i t y . m!rec

Nozzle Area Rat io

Nozzle Fressure Rat io

Thrust Coe f f i c len t (Vacuum)

Vacuum Speci f ic Impulse. ter.

Vacuum Thrust. N

c p p - I

Fuel-Rich Gas - - . -- 1.17

9%

26.6

1.132

R.73

5.1

11.0164

l . l bR

137.5

231

Expander Cycle

Turbine

24.4

359

1.23

Englne .;el qht , '~vnv!O&'- fl 1_f=f3n%

Engine Weight = 297 kg

Total Length = 154.4 cm

Total Diameter ' 311.4 cm

Del :vered Vacuum Spect f ic Impulre:

Node 1 ; 395.0 sec

h d e 2 - 44R.g sec

Vacuu Thrust. l b

Tot r l F l w Rate. l b l s u

n i x t u r t Ratio

Oyprn Flow b t e . l b / s u

RP-1 Flow Rate. lb lsec

hydmuen Flow Rate. lb/sec

Vacuul Thrust, l b

C W r Prtssure, psla

Nozzle A r m Ratio

T h m t Arta. in . 2

Throat D i a r t e r . in .

Nozzle Ex i t Area. in.'

Wozzlt Ex i t Dimeter. in.

Plug Cluster

h s t mrurt, l b

NubCr o f lbdules

Plug Cluster Area b t i n

Totr l Throat Area, ln.2

Total Ex i t ~ r ca ( " . i n s 2

Plug Cluster O i e t e r , in.

b p

77-I Includes base.

TABLE X X I X ( c o n t . )

Pbtn P w r

Outlet Flow Rate. lb/sec

Vo lmet r lc Flow Rate, GPM

NPSH. f t

Suctton Speclfic Spted. ( R P M ) ( C P ~ ) ~ / ~ / ( F ~ ) ~ ' ~

Speed. RPM

Discharge Pressure. p r i a

Head Rise, f t

I*nber of Stages

Specific Speed (N,). ( R P M ) ( ~ P ~ ) ~ ' ~ / ( F ~ ) ~ ' ~

Head Coefflclent

Impeller Tip Speed, ft/sec

Impeller Tip Diameter, in .

Horsepoutr

Ef f ic i tncy , 1

02/RP-I Module

Feed System L O X ~

RP-1 LOX 9 Punp

TABLE X X I X (cont.)

Gas Generator

RP-1 I n l e t Tenp.. O R

Chamber Pressure. psia

Canbustion Temp.. "R

Mixture Ratio

Ox. Flow Rate. lb lsec

RP-1 Flow Rate. lb lsec

Total Flow Rate, lb/sec

Turbines -- I n l e t Pressure, psia

I n l e t Temperature. OR

Gas Flow Rate. lb/sec

Gas Properties

C . Specific Heat a t Constant Pressure. ~!u/ib-ou

v. Ratio of Specific Heats

Shac t ~orsepower" )

Efficiency, : Pressure Rat io (Total t o S t a t i c )

11) I n c l u d e ~ r s e p o w e r penalty f o r boost punp dr ive flow.

Turbine Exhaust P e r f o m n c e

Turbine E x i t Pressure, psia

Turbine E x i t Total Tmp., OR

Gas Molecular Weight

Ratio of Speci f ic Heats

Character ist ic Exhaust Velocity. ft:sec

Nozzle Area Ratio

Nozzle pressure Rat io

Thrust Coef f i c ien t (Vacuum)

Vacuun Specific Impulse. <PC

Vacuum Thrust. l b

Expander LOX Cycle

Turbopune Turbine

02lRP-1 Fuel-Rich Gas

17.2

1613

26.6

1 .I32

2734

5:l

0.0364

1.618

137.5

52

Enpine Weight, Envelope and Performance

Engine Ueight = 655 l b

Total Length = 60.8 in .

Total Diameter = 122.6 in.

Delivered Vacuum Speci f ic Impulse:

Mode I = 395.0 sec

Mode 2 a 448.9 sec


po in t i s shown on Table XXX. The suct ion speci f ic speed must be reduced and the number o f pump stages increased from 1 t o 2 i n order t o keep the RP-1 pump spec i f i c speed a t a r:*sonable value. I t i s a lso estimated t ha t the RP-1 pump performance w i l l decrease from 60% t o 57%. Because of these adverse ef fects , para1 l e l , separate turbines were assumed for the gas generator cycle balance o f Table X X I X .

TABLE XXX. - LOX/RP-1 PUMP PARAMETERS FOR SINGLE SHAFT, SINGLE TURBINE DRIVE

S.I. UNITS

Main Pumps

Out le t Flow Rate, kg/sec

Volumetric Flo* Rate, m3/sec

NPSH. m 112 3/4 Suction Specif ic Speed, (RPM) (m3/sec) / (m)

Speed, RPM Discharge Pressure, atm

Head Rise, m

Number o f Stages

Specif ic Speed (Ns) . (RPM) (m3/sec)lf 2/ (1111~'~

Head Coeff ic ient

Impel ler Tip Speed, m/sec

Impel ler Tip Diameter, cm

Eff ic iency, X

LOX/RP-1 Module Feed System 7

Pump

ENGLISH UNITS

Out le t Flow Rate. lb/sec

Volumetric Flow Rate. GPM

NPSH, ft

Suction Speti f i c Speed, (RPM(GPM)~/ ' / (FT)~ '~

Speed, RPM

Discharge P~~essure, psia

Head Rise, ft

Number o f Stages

Specif ic Speed (NS), (RPM) (GPM) ' /~ / (FTl3l4

Head Coeff ic ient

Impeller Tip Speed. ft/sec

Impeller T i p Diameter, in.

Eff ic iency, X

SECTION V I

TASK I V - ENGINE PERFORMANCE, WEIGHT AND ENVELOPE PARAMETRICS


The objectives o f t h i s task were t o provide parametric engine performance, \

weight and envelope data f o r the tri propel 1 ant, dual -expander and plug c lus te r engine concepts. The parametric analyses were conducted on each concept t o determine the effects o f varying design th rus t level , th rus t s p l i t and Mode 1 area r a t i o upon the engines dimensions, dry weight and del ivered vacuum specif ic impulse. The analyses were conducted over the fo l lowing ranges:

Thrust Mode 1 Modu l e Engine Level, Thrust Overall Area Concept KN (K 10) S p l i t AreaRat io Ratio

Tr ipropel lant 66.7 t o 400.3 0.4 t o 0.8 200 t o 600 - (15 t o 90)

Dual-Expander 66.7 t o 400.3 0.4 t o 0.8 200 t o 600 - (15 t o 90)

Plug-Cluster 66.7t0400.3 0 . 4 t 0 0 . 8 2 0 0 t o 7 1 6 1 1 2 t o 4 0 0 (15 t o 90)

The th rus t chamber pressures f o r each concept were established by engine cooling evaluations. The maximum operating chamber pressures for each engine concept are 1 i s ted below as a funct ion o f t h rus t and th rus t s p l i t .

Thrust Engine Level, Thrust Mode 1 Thrust Concept KN ( K l b ) S p l i t Chamber Pressure atm (psia)

Tr ipropel lant 66.7 t o 400.3 (15 t o 90) 0.4 136 (2000)

66.7 t o 400.3 (15 t o 90) 0.5 136 (2000)

66.7 t o 400.3 (15 t o 90) 0.6 136 (2000)

66.7 (1 5 0.8 81.6 (1 200)

89 t o 4 0 0 . 3 ( 2 0 t o 9 0 ) 0.8 136 (2000)

V I , A, Objectives and Guidelines (cont.)

LOX/RP-1 LOXILH2 Thrust Thrust

Thrust Chamber Chamber Engine Level, Thrust Pressure, Pressure, Concept KN (K l b ) S p l i t atm (ps ia ) atm (ps ia )

Dual -Expander 66.7 (15) 0.4 81.6 (1200) 40.8 (600)

0.8 19.0 (280) 9.5 (140) P l u g c l u s t e r 66 .7 to400 .3 0.4 t o 0.8 20.4 (300) 20.4 (300)

(15 t o 90)

The maximum operating pressure f o r the dual-expander engine a t a t h rus t s p l i t o f 0.8 i s below the 34 atm (500 ps ia) minimum value l i s t e d i n the contract statement o f work. However, these cases, 12.9 t o 19.0 atm (190 t o 280 psia), were evaluated to complete the study matr ix,

The parametric data was generated f o r a LOXIRP-1 mixture r a t i o o f 3.1 and a LOX/LH2 mixture r a t i o o f 7.0 per the study guide1 ines. Because the

V I , A, Objectives and Guidelines (cont.)

p lug c l us te r o ~ e r a t i n g pressure i s low, the e f f ec t o f operat ing the LOX/LH2 modules a t a mix ture r a t i o o f 6.0 ra ther than 7.0 was a lso invest igated.

Other OTV engine requirements and gu ide l ines were l i s t e d i n Section 11, Tab1 es I V through V I I.

0. PARAMETRIC DATA

1. T r ip rope l lan t Engine

The base1 i n e 2perat ing condi t ions f o r t h i s engine a re a Mode 1 t h rus t o f 88964N (20,000 : bs), t h rus t s p l i t = 0.5, a nozzle area r a t i o of 400:1, and LOXIRP-1 and LOX/LH? mixture r a t i o s o f 3.1 and 7.0, respect ive ly . Baseline engine performance, weight and envelope data are presented on Table X X X I .

Performance, weight and envelope pred ic t ions f o r o ther study thrusts, t h r u s t s p l i t s and area r a t i o s a re presented on Table X X X I I , These data are shown f o r a Mode 1 operat ing t h rus t chamber pressure of 136 atm (2000 ps ia) . However, as prev ious ly noted, a t a t h r u s t s p l i t of 0.8 and a t h r u s t l e ve l o f 66723N (1 5,000 1 bs), the engine i s coo l ing l i m i t e d t o a chamber pressure o f 81.6 atm (1200 ps ia) . This operat ing po in t and the resu l t i ng data a re shown on Table X X X I I I . This data should be used a t t h i s po in t instead of the 136 atm (2000 ps ia ) data.

P lo ts o f some o f the parametric data have been prepared a t PC = 136 atm (2000 ps ia ) t o show the data trends. Mode 1 and 2 de l ivered performance i s shown as a func t ion o f nozzle area r a t i o f o r various t h rus t s p l i t s a t the base1 i ne Mode 1 t h rbs t o f 889643 (20,000 1 bs) on Figures 68 and 69, respect ive ly . Mode 1 and 2 de l ivered performance as a func t ion of t h rus t f o r various t h r u s t s p l i t s a t a basel ine area r a t i o of 400:l i s shown on Figures 70 and 71, respect ive ly . Performance increases w i t h increasing t h r u s t l e ve l because the k i n e t i c s loss i s reduced. Mode 1 performance decreases w i t h increasing t h rus t spl i t because the amount o f RP-1 used increases. Mode 2 performance decreases w i t h increasing t h r u s t s p l i t because the Mode 2 t h r u s t and chamber pressure decrease which increase the k i ne t i c s loss.

Engine dry weight i s shown as a func t ion o f nozzle area r a t i o and t h rus t s p l i t on Figure 72 f o r a basel ine Mode 1 t h rus t o f 88964N (20,000 1 bs) . Weight decreases w i t h increasing t h rus t spl i t because the LOX/RP-1 t h rus t con t r ibu t ion i s greater which r e s u l t s i n l i g h t e r engine components. The e f f e c t o f Mode 1 t h rus t upon the engine dry weight i s shown on Figure 73 f o r the basel ine t h r u s t s p l i t o f 0.5.

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Engine envelope data i s shown on Figures 74 and 75. Figure 74 shows the envelope data as a funct ion o f nozzle area r a t i o f o r the basel i ne Mode 1 t h rus t o f 88964N (20,000 l b s ) and th rus t s p l i t o f 0.5. Stowed length does no t vary s i g n i f i c a n t l y w i t h nozzle area r a t i o bccause the f i x e d nozzle length i s always greater than the rad ia t i on cooled nozzle extension. Stowed length I s ca lcu la ted assum~ng t ha t the r ad ia t i on cooled nozzle extension can be re t rac ted t o the th roa t plane. The f i x e d nozzle length i s based upon heat t rans fe r analyses which establ ;shed the minimum area r a t i o r ad ja t i on cooled nozzle attachment points. Figure 75 presents the envelope data as a func t ion o f Mode 1 th rus t a t the basel ine Mode 1 area r a t i o and t h rus t s p l i t values o f 400:i and 0.5, respect ively.

2. Dual -Expander Enqi ne

The base1 ine operat ing condi t ions f o r t h i s engine a re a Mode 1 t h rus t o f 88964N (20,000 lbs ) , t h rus t s p l i t = 0.5, a Mode 1 nozzle area r a t i o o f 200:l and LOX/RP-I acd LOX/LH2 engine mix ture r a t i o s o f 3.1 and 7.0, respect ive ly . Basel i ne engine performance, weight and envelope data are presented on Table X X X I V .

Performance, weight and envelope pred ic t ions f o r the o ther study thrusts, t h rus t s p l i t s and Mode 1 area r a t i o s are presented on Table XXXV. The data were establ isned f o r chamber pressure values r e s u l t i n g from cool i ng l i m i t a t i o n s prev ious ly l i s t e d ar,d are shown on Figure 76.

F l o t s o f some o f the parametric data have been prepared t o i n d i - cate the trends. Figures 77 arid 78 show the Mode 1 and 2 de l i ve red performance as functions o f nozzle area r a t i o and t h rus t s p l i t f o r a basel ine Mode 1 t h r u s t o f 88964ti (20,COO I bs). The Mode 2 nozzle area r a t i o s t ha t a re obtained f o r various Mode 1 area r a t i o s are shown on Figure 79. Mode 1 de l ivered performance decreases w i t h increasing t h rus t s p l i t because a greater con t r ibu t ion af the t h rus t i s provided by LOX/RP-1 propel l an ts . Mode 2 performance decreases w i t h increasing t h rus t s p l i t because the Mode 2 t h rus t and chamber pressure are reduced s i g n i f i c a n t l y and t h i s r e s u l t s i n increased k i n e t i c s loss. The e f f e c t of Mode 1 t h r u s t l e ve l upon the engine performance i s shown on FSgures 80 and 81 f o r the base- l i n e Mode 1 overa l l area r a t i o o f 200:l.

The Mode 1 perfor;na:cr\ r ! l the dual-expander engine a t a given overa l l Mode 1 area r a t i o i s less than t ha t of the t r i p r o p e l l a n t engine f o r two reasons. F i r s t , the lower operat ing chamber pressure r esu l t s i n increased k i r ~ e t i c s loss. Second, the area r a t i o through which the LOX/LH2 combustion products i s expandad i s less that1 the overa l l Mode 1 area r a t i o . This means t h a t more of the performance con t r ibu t ion i s obtained from the LOX/RP-1 propel lants. For the t r i p r o p e l l a n t engine, a l l the

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MODE 1 OVERALL NOZZLE AREA R A T I O

Figure 79. Dual-Expander Engine Mode 2 Nozzle Area Rat io

h o h - L, . *-.- a =7.-.-.- i , , ., - . - . *.w-, - . .-- -. . --. -.. 1,

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V I , 0, Parametric Data (cont.)

prodlrcts o f combustion a;.e expanded through the f u l l area r a t i o . The Mode 2 performance i s I; 1 i t t l e lower than the tr: y o p e l l a n t engine because o f h igher k i n e t i c s lu:,ses associated w i t h lower chamber pressure operation.

Engine d r y eight i s shown on Figure 82 as a func t ion of Mode 1 ove ra l l nozzle area r a t i o and t h rus t spl ! t a t the basel ine Mode 1 t h rus t of 88964N (20,000 1 bli). Engine weight increases w i t h increasing t h r u s t s p i i t bechus; the operat ing chamber pressure decreases. This r e s u l t s i n very heavy nozzles f o r the high required area r a t i d s (F igcrc 79). As discuss2d previously, the chamber pressures a t a t h r u s t s p l i t o f 0.8 a re below p rac t i ca l operat ing pressures f o r pump-fed engines. The data i s included on ly t o complete the study matr ix and t o i nd i ca te the danger o f ex t rapola t ing the study resu l t s . For example, a l i n e a r extrapola- t i o n o f the weight data obtalned a t t h rus t s p l i t s o f 0.4, 0.5 and 0.6 would r e s u l t i n an obviously s i g n i f i c a n t e r r o r a t a t h rus t s p l i t o f 0.8.

The e f f e c t o f Mode 1 t h rus t on the dual-expander engine dry weight i s shown on Figure 83 f o r the basel ine t h r u s t s p l i t o f 0.5 and various Mode 1 ove ra l l nozzle area r a t i o s .

The dual-expander engine envelope data i s shown on Figures 84 and 85. F iyure 84 show; the envelope data as a funct ion o f the Mode 1 overs:l area r a t i o f o r the basel imit ! Mode 1 t h r ~ s t and t h rus t s p l i t values of ;;964N (20,000 1 bs) and 0.5, respect ive ly . Figure 85 shs:rs the envelope data as a f u ra t i on o f the Mode 1 t h r u s t f n r the basel ine t h rus t s p l i t of 0.5 and an ove ra l l Mode 1 area r a t i o o f 200:l.

3. Pluq Cluster Engine

The basel ine operat ing cocd i t ions f o r t h i s engine are a Mode 1 t h rus t l e v e l o f 88964N (20,000 Ibs ) , t h r u s t s p l i t 0.5, and ove ra l l Mode 1 geometric area r a t i o o f 358:l (module area r a t i o = 200: l ) and LOXIRP-1 and LOX/LH? engine mix ture r a t i o s o f 3.1 and 7.0, respect ive ly . I n addi t ion, based upon the r e s u l t s of Contract NAS3-?0109, Unconventional Nozzle Tradeoff Study (Ref 3), a l l the modules a re assi~med t o touch (zero gap) i n Mode 1 and a zero length p lug and 1 S nodules are used. Baseline engine performance, weight and eni;e!qe dat'j a re pr-sentzd on Table X X X V I .

Performance, weight and envelope pred ic t ions f o r the o ther study Mode ! thrusts, t h rus t s p l i t s and ove ra l l Mode 1 area r a t i o s a re presented on Table X X X V I I . A l l o f these data were establ ished f o r a t h rus t cha~qber pressure o f 20.4 atm (300 os ia) . This low chamber pressure value \:as selected because o f problems associated w i t h cool i ng the LOX/RP -'I cod l~ ies

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V I , B, Parametric Data (cont.)

w i t h e i t h e r LOX o r RP-1. The data has been generated f o r RP-1 cooled LOX/RP-1 modules. Cooling w i t h RP-1 assumes t h a t some o f the impur i l i e -2 are removed from t h i s propel lant t o increase the bu lk temperature l i m i t t ha t i s normally imposed t o avoid cracking, gumming and coking o f the RP-1. I t shculd be noted t ha t the cool ing problems would be much less severe i f other hydrocarbons such as, methane o r propane were used i n the mixed- mode plug c luster . Inves t iga t ion o f the propel lants were beycnd t h i s cant ract scope o f work.

P lo ts of sme o f these parametric data have a lso been prepared t o show the trends. Figures 86 and 87 show the Mode 1 and 2 del ivered performance as functions o f Mode 1 ove ra l l area r a t i o and t h rus t s p l i t for the baseline Mode 1 t h r u s t o f 88964N (20,000 lbs). Overal l Mode 1 area r a t i o was selected as the abscissa f o r the p l o t s i n accordance w i t h the statement of work and re la tes t o ove ra l l engine size. For a zero leng th plug w i t h zero gap, the overa l l geometric area r a t i o i s not r e a l l y a meaningful parameter i n the performance calculat ions. Module area r a t i o i s more i nd i ca t i ve o f the system performance potent ia l . Therefore, the modu.ie area r a t i o s t h a t are obtained w i t h 10 touching modules a re p l o t t ed as a funct ion o f overa l l Mode 1 area r a t i o on Figure 88. I n Mode 2 operation, the LOX/RP-1 modules are i nac t i ve and the c l us te r ( o r geometric) area r a t i o increases and gaps are created between the modules. However, f o r t i le zero length plug, on ly the module area r a t i o i s again o f any rea l importance i n the performance calculat ions. I n other words, t h i s plug c l us te r performance i s based upon the module performance corrected f o r the module t i 1 t angle and the base pressure cont r ibut ion. Because on ly two modules are operating i n Mode 2 a t a t h rus t s p l i t cf 0.8, the base pressure e f f ec t s are expected t o be neg l i g i b l e and Mod! 2 performance f o r these cases i s based e n t i r e l y upon the module performance wS t h a t i 1 t angle correct ion. This i s why the ove ra l l Mode 2 area r a t i o and module area r a t i o s are shown as equal f u r these cases i n the tabular data. Mode 1 performance (Figure 86) decreases w i t h increasing t h rus t s p l i t because the LOX/RP-1 t h rus t con t r ibu t ion i s greater. Mode 2 performance (Figure 87) also decreases w i t h increasing t h rus t s p l i t because the base pressure cocitr i bu i ion i s redwed a s tne gap betweevt :rlodul es i ncreases.

The e f f e c t o f Mode 1 thr1;st leve l upon Mode 1 and 2 perfcrrmance i s shown on Figures 89 and 90, respect ive ly . These data are presented for the baseline overa l l area r a t i o ,7f 358 and module area r a t i o o f 200.

The plug c l us te r engine performance i s r e l a t i v e l y low because the lbw th rus t and low operat ing chamber pressure o f the modules resu l t s i n l a rge r k i ne t i c s losses than i i iqh th rus t , h igh pressure engines such as the tri propel l a n t concept.

Lal U s 1

*r an 0 ace L L = al en

VI, B, Parametric Data (cont.)

Engine dry weight i s shown on Figure 91 as a function of Mode 1 overall area ratio for various thrust spl i ts a t the baseline Mode 1 thrust level of 88964N (20,000 1 bs). Engine weight increases w i t C increasing thrust spl i t because the LOXIRP-1 thrust chamber modules are heavier tha:i the LOX/LH2 modules and this more than makes up for lighter turbomachinery weights. The LOX/RP- I module chambers are longer (1 iquid-liquid injection) than the LOXILH2 module chambers (1 iquid-gas injection) to meet the 98% combustion efficiency requirement and this results i n heavier weights.

The effect of Mode 1 thrust on the plug cluster engine dry weight i s shown on figure 92 for the baseline thrust spl i t of 0.5 and various Mode I overall area ratios.

The plug cluster engine envelope data i s shown on Figure 93 and 94. Figure 93 shows the envelope data as a function of the overall Mode 1 area ratio for the baseline thrust of 88964N (20,000 lbs) and thrust sp l i t of 0.5. The equivalent engine length i s defined as the length from the conventional engine mounting plane to the module exits . The engine length i s defined as the length from the t o p of the modules to the module exits (see the sketch on Figure 93). The equivalent. length parameter is introduced because some of the propellant tank can fit i n the plug recess which i s not possible with other engine types like a single bell nozzle. Figure 94 shows the envelope data as a function of Mode 1 thrust for base1 ine thrust spl it, overall area ratio and module area ratio values of 0.5, 358 and 200, respectively. The plot and the tabular data show that the plug cluster engine diameter exceeds the 447 an (1 76") diameter 1 imitation a t the majority of the overall nozzle area r a t i ~ s a t thrust levels greater than 177.9 KN (40,000 Ibs). All the data was calculated t o complete the study matrix but i t should be recognized that engines with diameters greater than 447 cm (176") will not f i t within the current shuttle payload bay.

The effect of the module operating chamber pressure and LOXILH2 module mixture ratio upon the engine performance was also investigated. This was done to aid in comparing the data generated under this contract w i t h that established for the Unconventional Nozzle Tradeoff Study (Ref. 3) and to show the sensitivities. This peripheral study was conducted a t the baseline thrust level of 88364N (20,000 lb).

Tables XXXVIII and X X X I X can be used to compare the plug cluster engine characteristics for LOX/LH2 module mixture ratios of 6.0 and 7.0 with the modules operating a t 20 atm (300 psia) chamber pressure. The LOXIRP-1 module mixture ratios for a l l cases i s 3.1. Table XXXVIII shows that a 6 to 7 sec performance gain i s achieved in .%de 2 i f the LOX/LH2 module mixture ratio i s reduced from 7.0 to 6.0.

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V I , B, Parametric Data (cont.)

Tables XL and XLI present the plug c l us te r charac te r i s t i cs fo r module operat ing chamber pressures o f 34 atm (500 ps ia ) and LOXILH2 module mixture r a t i o s o f 6.0 and 7.0, respect ively. These tab les show tha t the plug c! us te r performance can be increased apyox imate ly another 2 t o 3 secs i f the module operat ing pressure can be increased. As noted i n previous s,>ctions, the LWRP-1 and no t the LOX/LH2 module l i m i t s the plug c l us te r operat ing pressure. The Mode 2 performance generated f o r a m-ixture olr 6.0 a t 34 atm (500 psia) i s comparable t o the Ref. 3 data.

A 1:o~zarison o f a l l data on Tables X X X V I I I through XLI ind icates t h a t both Cia loiv operating pressure of the modules and low module t h r u s t would s e m Lo d r i w the "optimum" operat ing s i x t u r e r a t i o o f the LOXILH2 modules from 7.0 t o 5.0.

P S - O m m * * O m ~ * w 0 * n o o U m n w ~

Y -X ~ ~ l o - ~ e ~ o - ~ C . o o r . B L ~ m ~ t w c ..rrr.~rr-.&.r..a-rr* r r y r -.r -0 a- nd

X O Y V .

*-- L , . L C L o O O O O m n L ~ m O ~ ~ o ~ ..................... 8%;: SO- 4 - r n n r r r n r e W l l 0

SL.;TION V I I

CONCLUSIONS AND RECOMMENDATIONS

A. CONCLUSIONS

The conclusions which were derived from the resu l t s o f t h i s study are discussed herein. These conclusions cover the resu l t s o f 61 1 study tasks and are discussed f o r each engine cnnccpt invest igated.

1 , T r i propel 1 an t Engine

Hydrogen cool ed tri propel 1 ant engines are p rac t i ca l t o a t 1 east 136 atm (2000 ps ia) f o r ranges o f t h r u s t from 66.7 t o 400.3 KN (15K t o 90K l b f ) and t h rus t s p l i t from 0.4 t o 0.6. A t a t h r u s t s p l i t o f 0.8 and 66.7 KN (15K lhf) , the t r i p r o p e l l a n t engine i s cool ing l i m i t e d t o about 81.6 atm (12CO psia). However, a t o ther t h r u s t leve ls , a ~ o o l i n g l i m i t was no t reached f o r t h i s t h rus t s p l i t o f 0.8.

The t r i p r o p e l l a n t engine i s no t power balance l i m i t e d and reasonable pump discharge pressures were achieved a t a l l t h r u s t s p l i t s investigated. Operation o f the t r i p r o p e l l a n t engine cc~ponents a t both the Mode 1 and Mode 2 design condit ions was s lso determined t o be p rac t i ca l .


Hydrogen cool ing o f t! . dual-expander engine w i t h a p a r a l l e l f lw path f o r cool ing o f the inner and outer chambers i s recomnended. This engine concept proved t o be cool ing 1 im i ted and the maximum chamber pressure i s a funct ion o f both t h rus t and t h r u s t s p l i t . The fo l low ing chamber pressures were establ ished a t a basel'ine t h r u s t o f 88964N (20,000 l b f ) :

Central LOXIRP-1 Annular LOXILH2 Thrust Chamber Pressure, Chamber Pressure, Spl i t aim (ps ia ) atm (ps ia)

Maximum operating pressures increase w i t h increasing t h r u s t 1 eve1 . A t the upper end o f the t h rus t range, 400.3KN (90K l b ) , the chamber pressures are:

V I I , A, Conclusions (cont.)

Centrdl LOX/RP-1 Annular LOX/;H2 Thrust Chamber Pressure, Chamber Pressure, spl i t atm (psia) atm (psid)

The abuve tables show tha t a th rus t s p l i t o f 0.8 appears t o be impractical f o r a pump-fed dual-expander system.

The dual-expander engine i s not power balance l im i ted and the design operating conditions f o r components i n both modes o f operation i s pract ical .

3. Plug Cluster Enqine

Cooling o f the LOX/LH2 module o f the plug c lus ter engine i s pract ical ovei the en t i re chamber pressure range o f 20.4 t o 68 atm (300 to 1000 psia) investigated. However, oxygen cool ing o f the LOX/RP-1 module was found to be impractical over the en t i re chamber pressure range and RP-1 cooling a t 20.4 atm (330 psia) i s feasible orlly i f the coolant bulk temperature l i m i t o f 589°K (600°F) can be exceeded. This holds t rue over the en t i re thrust range o f 66.7 t o 400.3 KN (15 t o 90K l b f ) investigated.

Because o f the low design module chamber pressures, 20.4 atm (300 psia), operating the LOX/LH2 module a t a mixture r a t i o 7.0 resu l ts i n a s ign i f i can t Mode 2 performance penalty compared t o a mixture r a t i o of 6.0.

The plug c lus ter exceeds the shut t le diameter constraint o f 447 cm (176 in.) a t a thrust level o f about 177.9 KN (40K l b f ) .

B . RECOMMENDATIONS

The recomnendations f o r advanced techno1 ogy and fu r ther study e f fo r ts that were i den t i f i ed during the course o f t h i s study program are sumnarized i n the fol lowing paragraphs. Items o f general nature pertaining to a l l three engines and items peculiar t o a par t i cu la r engine concept are ident i f ied .

V I I , 5, Reconnendations (cont.)

1. General

Conduct a preliminary design study o f the three baseline engine concepts and t h e i r components t o provide engine and component lay- out drawi ngs .

Conduct an eng:'r?e study t o evalucie the us? o f methane and/ o r propane as fuels f o r each o f the engine cc;~cepts.

O Design, fabr icate and tes t a small, high speed hydrocarbon turbopunp t o add t c the data base obtained under Contracts NAS 3-17794 and NAS 3-17800 for hydi-oqen and cxygen turbopumps suitable f o r the OTV application.

" Evaluate, design, fabricate, and tes t bearing and seal packages f o r use i n long 1 i f e , small, high speed cryogenic and hydm- carbon turbopump designs .

O Ccnduct an experimental study t o evaluate the economic feasi- b i l i t y o f making "pure" RP-1 t o avoid gumning, cracking and coking prob-. 1 ems i n reuseabl e hydrocarbon engi nes .

2. Tripropel l a n t E ~ q i n e

O Design, f a L r i c a t e a n d t e s t a tripropellantinjectorusing f ue l - r i ch LOX/LHz, ox id ize* - r i ch LOX/LH2, and fue l - r i ch LOX/RP-1 gases as the propellants.


O Conduct a cold f lcw experimental program t o evaluate the dual -expander aerodynamic performance and nozzle design c r i t e r i a .

O Conduct a design analysis study on a conibined regenerative and t ranspi rat ion cooled chamber concept to determine the f e a s i b i l i t y o f i r!creasi ng the operating thrust chamber pressure.

' Conduct a design study o f the central chamber to evaluate the f e a s i b i l i t y o f manufacturing a dual-wall m i l l - s l o t t ed copper chamber.

4. Plug Cluster Engine

" Conduct a study to establ ish the f e a s i b i l i t y and system design impacts associated w i th +ydrogen cool ing o f the LOXIRP-1 modules.

VII, 8, Recomnenddtions (cont.)

* Design, fabricate and tes t long l i f e , low thrust, regenera- t i ve l y cooled thrust chamber modules f o r both LOXJLH2 and LOX/RP-1 propellants.

" Extend the plug c luster cold flow experimental data base to improve performance prediction techniques.

Conduct a hot - f i re demonstration of a plug c luster engine to evaluate ign i t ion o f mult iple chambers, hydraulics and interactions o f mu1 t i p l e modules and t o ver i fy performance.

REFERENCES

1. Beichel , R. and Sal keld, R., Mixed-Hode Propulsion Systems for F u l l Capabil i t y Tugs, AAS Paper No. 75-162, August 1975.

2 . Luscher, W.P. and Hel l ish, J.A., Advanced High Pressure Enqine Study. f o r Mixed Mode Vehicle Applications, Final Report, Contract NAS 3-19727, NASA CR-135141, ALRC, Jan. 1977.

3. 0 'Rrie~ , C. 3 . . Unconventional Nozzle Tradeoff Study, Final Report Contract NAS 3-201 09, NASA CR-159520, ALRC , June 1 978.

4. Svehla, R.A. and McBride, B.J., Fortran I V Computer Program f o r Calculation o f Themdynamic and Transport Properties o f Complex Chemical Systems, NASA TN D-7056, January 1973.

5. McCarty, R.D. and Weber, i .A., Thermophysical Properties of Oxygen From the Freezing Line t o 600°R f o r Pressures t o 5000 psia, NBS Tech. Note 363, National Bureau o f Standards, Cryogenics Div.. Boulder,

- - - Colorado, Ju ly 1971.

6. Roder, H.M. and Weber, L.A., ASRDI Oxygen Technology Survey: Volume I, Thermophysical Properties, NASA SP-3071, National Aeronautics and Space Administration, Washington, D.C., 1972.

7. Weber, L .A., Extrapol at ion o f Themphysical Properties Data f o r

8. Hanley, H.J.. McCarty, R.D. and Sengers, J.V., Viscosity and Thermal Conduct iv i t Coefficients o f baseous and L iqu id Oxygen, NASA-CR-2440, National Aeronautics and Space Administration, Wat. hinqton. D.C.. - August 1974.

9. McCarty, R.D. and Weber, L.A., Thermo~hysical Properties of Para- hydroqen from the Freezing L iquid Line t o 5000°R f o r Pressures t o 10,000 psia, NBS Tech. Note 617, National Bureau of Standards, Cryogenics Div., Boulder, Colorado, Apri 1 1972.

10. L i u id Pro e l lants Manual, Uni t 20, RP-1, Chemical Propulsion In fo r - -he Johns Hopki ns Universi ty Appl ied Physics Laboratory, S i l ve r Springs, Md., January 1966.

11. Dean, L.E. and Shurley, L.A., Characteristics o f RP-I Rocket Fuel, Tech. Report TCR-70, Contract F04(645)-8, Wezpon System 107A, Aerojet-General Corporation, Sacramento, Calif., 14 February 1957.

REFERENCES (cont . )

12. Cal how, e t a1 . , _Investigatiol~ of Gasems Propellant Combustion a.rd P.ssociated Injectl?yCbwtber Design Gui del i nes, NASA CR-121234, Contract NAS 3-l437$, ATR~, 31 July 1972.

13. Roark and Young, Formulas f o r S t ress an?sfrpL:, Fif th Edition, McGraw Hill Book C o . , 1975.

14. Sergant, R.J., An Experimental Hot Model Investication of a Plug Cluster Nozzle Propulsion System, Par t 1: Base Thermal and Pressure Environment fo r a Module Chamber Pressure of 300 psia and Simulated A1 t i tudes t o 150,000 f e e t , CAL No. YM-2045-Y-5 ( I ) , Cornell Aeronautical Laboratory, Inc. , September 1967.

15. Combuction Effects on Film Cool i ng, HOCOGL Users Manual , Contract NAS 2-17813, ALRC, 15 July 1975.

16. Smith, J .P., Systems Improved Numcri cal Di fferenci nq lnalyzer (SINDA! : User's Manual , TRW Systems Group, Redondo Beach, Cal i f . , TRW-14690- H001 -RO-00, Apr . 1971 .

17. Hess, H.L. and Kunz, H.R., A Study of Forced Convection Heat Transfer t o Supercrit ical Hydroqen, ASME Paper No. 63-WA-205, Nov. 1963.

18. Taylor, - . M. . F., Applications of Variable Property Heat-Transfer and Frict ion Equatians to Rocket Nozzle Coolant Passages and Comparison w i t h Nuclear Rocket Test Results, AIAA Paper No. 70-661 , presented 15 June, 1970.

19. Hines, W.S., Turbulent Forced Convection Heat Transfer t o Liquids a t Very High Heat Fluxes and Flowrates, Rocketdyne Research Report No. 61-14, Nov. 1961.

20. Rousar, D.C. a i~d Spencer, R.G., Su e r c r i t i c a l Oxygen Heat Transfer, +: Final Report, Contract NAS 3-20384, NAS CR 133- 1977.

21. JANN.AF Liquid Rocket Engine Performance Prediction a d Evaluation Manual, CPIA Pub1 icat ion 246, Apri 1 1975.

22. Dennies, F , Marker, H . E . , and Yost, M.C., Advanced Thrust Chamber Techno1 oqy , Final Repcrt , Contract NAS 3- 1 7825,- Rocketdyne, 5 July 1977.

23. Liquid Rocket Engine Centrifugal Flow Turbopum~, NASA Space Vehicle Design Cri t e r i a Monograph, NASA SP-8109, December 1973.

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