—GQNKlBENTIAL

TNVESTIGATION OF THE EFFECT OF VELOCITY DIAGRAM FRRAMETERS ÖHINLET TOTAL·FRESSURE DISTOHTION THROUGH SIGLE—STAGE

I

SUBSONIC AXIAL·FLOü COMPRESSORSbr

George C., Iashby, Jr.

Thßßis submitted to tha Graduate Faculty of th

Virginia Polytechnic lnstituta

in candidacy tor the degree ofHASTER OF SCIEHCE IinI

Aeronautical Engineering

AFPROVED; APPROVED:

. I . r/‘,"‘

CVDirectorof Graduate Studies Head of Department

. g ,’ A"/. R 9 _$‘ —

LIÜ :I•

·

__Deanof Engineering Major Professor

Mw 1951

Blackeburg, Virginia

CONE·“IDiLNTIA”L

I

fi..2..

TABLE

ÜFPAGE

3

ix

B

ILO

21Apparat„us.. 21

Inatrumentntion.........„.......„„»„. 25

Test Program and Procedure....... . „ „..... 3:}

Presentation of Data......„ .......... . 3133

bl

mu;. smumx...................„...... LLxx. Awamamuma................... . . „ L6

D7

xx. vim „............... . . ......... L8xu:. Acpxmxx L9

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2 CONFIDENPLAL.. 3 -

I. LET GF FIGLRES

FIGUHE PAGE

1. Compressor Rotor Velocity Diayam . . . . . . . . . . . . . . ll

2. Superposition ot Diatorted Flor Velocity Diagram onUndistorted Flor Velocity Diayam . . . . ...... . . . 12

3. Ve1ocityDiag*amAna1ysed ................. lllL:. Schematic Diagraxa ot Test Compressor Showing Blade Rors

and Instrzmntation Positions............. . . 225.RotorUsedinInvestigation................. 2L E

6. sketch showing lnstrumentation at Each Meaeuring Station . . 267. Detailso£'Prism-Type?robe.................. 278. 26-Tube Tota1—Preseza·s Hase Used to Mensur: Rod Yéafee at

Stationl.........................289. 25··'i'ube Shieldsd Total-Pressure Raks Used to I-{ensure Rod

Wake at Station 2.................... . 29 e

10. Comariaon of Measured end Eatimted Dovmstream Rod Wakss

With the Heaaursd Upstream Wake for Five Test Configurm-—tions st Approximately Desigz Angle ot Attack ...... . 3h g

ll. Comparison ot Hessured and Eatimated Dornstream Rod éäakea

With Heneurod Upstream Wake tor Rotor Alone; E ¤· Ed,Configuration at Three Angles of Attack . . . . . . . . . „. 36

12. Comparison of the Streamline Pathe of the Undistorted and

Distortsd Flora inthe Blade Passage . . . . . . . . . . . ho ;

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C 0 N F I D E N T I A L

ERRATA SHEET

Page 13.- Add assumption 5, '*The entropy rise across therotor is the same for both the distorted and undistorted flows.

Appendix.- The equation for the energy added by the rotor is

H2 - Hl Hlvtll (Hi)

. v2since H = h + 2j·, the energy added by the rotor can also beexpressed as v 2 v 2

H H — H H + 2 2~2‘*1‘ 2'l ‘?€‘°"°"ä" (22)

. . dn .Using the fundamental energy equation dh = —— + tds and assumingincompressible flow results in 2

„ P2 " P1H2 — Hl —— t(s2 - sl) + --5- (A3)

where s = entrcpy.Eqnating (Al) and (A3) and rearranging gives

P PP p 2 U2Vt,2 * UlVt,1 ‘ 2(S2 ‘ S1) (22)

First paragraph on page 50 stays the same.

Second paragraph is to be replaced by!

Since U2 and Ül are constat for a given Velocity diagram,p is constant for incompressible flow and t(s2 - sl) isconstant uder assumption 5 of Analysis. P2/p, Pl/p, and Vt 2are the only variables with respect to Vl2/2 in equation (AA).

Replace ää (p2 - pl) in equation (A7) with t(s2 - Sl)

and correction to the Appendix will be complete.

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II. INTROLUCTION

One of the most important poblems associated with high-speed gas—

turbine powered aircraft is reduced compressor, and therefore engine,

performance reeulting from nonuniform distributions of total pressure

at the comessor entrane, hereinafter referred to as inlet total-

pressue distortions. This inlet total•pressure distortion can effect

compessor performance in several ways. It may result in prenature

surge and therefore reduced engine acceleraticn margin and altitude

operating limits, it may result in rotating stell, in increased

compressor—blade vibratory stresees, and/or in rednced engine mass flow

(refs. 1, 2, and 3).

The tern "inlet“ usually rsfers to the air intake and its diffuser;

however, distcrtions which develop in the ducting from the diffuscr exit

to the compressor entrance are also classified es inlet distortions.

An inlet is designed primarily to accommodate the mass flo¤·required.by

the engine when the aircraft is flown at its design flight speed and

altitude. It is also designed to povids the mass·flo¤ requirements

over ae large a range of flight conditions as possible. When the air~

craft is operated in the vieinity of its design—flight conditions the

flow distortions which develop in the inlet are usually small enough n

to be tolerated. However, operation of the engine at off·design con·

ditione or the aircraft at large angles of attack (or yes) may result

in large inlet flow distortions.r

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CONFIHENTIAL Ü- 5 -

Flow distortions can have several causes and are eceeehat dependent

on flight speed (ref. h). At subsonic speeds who the engine is operated

at off·design conditions or when th aircraft is flown at high angles of

attack or ya: a distortcd flow may result because of flow separation from

the inlet lip. At supersonic speed: with either the off—design or high

angle—of—attack condition, a distorted flow may result because ef non·

uniform conpression at the inlet hroat. Th diffuser and the dnctlng

from the diffuser to te conpreasor entrance can also he sources of

distortione. Their design is dependent on the internal design of the

aircraft and often has to be cospromised to avoiu interforenoe with the

pilot*s conpartnent, structural mamers, and/or auniliary equipment.

If the flow ie diffused or turned too rapidly, flow distortions result

due to flow sepration from the walls.

Several investigations have been conducted to determine the

effects of inlst total—pressur• distortion on the performance of

specific engines (6.;., refs. 2, S, and 6). In reference 7 a distortion

factor which ie a function of the circumferentiel extents of the dis·

torted and undistorted flow regions and the magnitude of the distortion

is correlated with a blade stall function. These studies indioate in

general what engine erformance penalties are expected·with a distortion

of given msgnitude and oxtcnt but dc not provide a solution to the

problem.

In fact, up to the present time, the only approach to the solution

of th problem has been that of reducing the dietortion before it

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reaches the compressor. References 1 and 2 show that internal

boundary·layerlhleed at the inlet thoat will redue the tctal~

pressure distortions. They also show that the dietortions say be

reduced before tey reach the compressor entrance wenyhetter mixing

is povided in the inlet ducting by increasing the diffuser length, hy

contracting the exit of the diffuser, or by using screens er freely

rotating fans, However, since these methods do not completely eliminate

the distortion and result in weight, volue, and preeeurc·recovery

penaltiee, other means of reducing the distortion need to be found.

Investigations of th effect of inlet totsl~preseure distortions

on the performance of specific engines (refe„ 2, S, und 6) show that

some distortions were eliminated within th compreseor and those which

persisted through the whole engine ere greatly reduceds These results

indicste that sone compreesor designs ay he more effective in redcing

an inlet total—preesure distortion than others. If the oriterion can

be foud for designing cospressors which will efficiently eliminate

inlet tota1~pressure distortions within the first few stages, te

sight, volume, and preesure—reoovery penaltiss which ecoompany the

previously mentiond methods of reduing the dietortion before it

reaches the cospressor need not be endured.

The end result of a compressor stage dcsign„sre the velocity

diagrame at the design radii. when the flow entering a compressor g

stage has s region of low total pressue and therefore low velocity,

the velocity diagrams in this region will not be the see as deeign„

Süße? I;E;.%@iä‘lAL.•. 7 „

A comparison of velocity diagems where only the entermg veloclty was

varisd shows that the retor reisee the total ereeswe cf the lm:

Velocity flow nom than it does the total goressure ef the high velocity

flow; therefore, in general, am inlet total·tg>•reeeuve distortion will ba

redueed ecrese a. roter. The purpose of me present investigation is to

clatermine the velocity diayam which is most effective in reduciug

inlet tets1•·preesu:•e distortions. The results of this irxvestigstien

were verified by the introduction of a mall disturhence (red wake}

wstream of e eomprssaor stage.

cs

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III• SYHBOLS

cp specific heat of air at conetant pressure, ft—~lb/slug—°R

c, specific heat of air at constant volume, ft—·lb/s1ug·—°R

ii total enthalpy, (11 + ia-) ft··lb/slug

u internal energ, ft··lb/slug

p static pressure, lb/eq ft

P total pressure, lb/eq ft

dP total·-pressure difference between the undistorted flow and

point in dietorted flow, lb/eq ft

q dynamic pressure, épvz, lb/eq ft

R perfectrgae constant, ft·-lb/slug-·°R

t static temperature, °R

U blade speed, ft/sec

V velocity, ft/sec

AVt change in tangentisl Velocity across rotor, ft/secVa

c flow coefficient, TJ-

c angle of attack relative to blade chord, {im ·· l, dag

5 flow angle meaeured from uis of rctation, dog6 turning angle, 51,, — 52,,, deg

£ b1ads—setting angle (angle between blade chord and axis of

rotation), deg

p air density, slugs/cu ft

c0sFI¤Em*IAL

COHEIBENIIAL·9 · v

Subscriptsz

1 upetraam of guide vane

1 upetream ot roter

2 downstream of roterat

axial directiond design condition

R relative coonrdimteet tangential direction

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•. lg} .„

IV. ANALXSIS

A cozapreesor roter velocity diagram at a given radios is shown in

Figure 1. The flow enters the blade row axially on absolute coordinstes

with a velocity vl. Relative to the blaues, the entering velocity and

air inlet angle are Vw and sm, respectively. The flow is turned

in the blade paasage and exits the bladee on relative coordinates with

a velooity V2R at an angle of $22. On absolute coordinates, the flow

has an exit velocity end direction ot V2 and 532, respectivelgn

An inlet total···preeeure diatortion can have its variation in the

radial or oireumferential direction. The ensuing discussion considers

oironmferential dietortione in the flow et a given blade element without

regard to the influence of the flow at other blade elesents• Figure 2

shows the circumferential velocity profile, at a given radios, of a

flow with a distortion entering e comressor rotor—··blade row. Although

the engle of attack relative to the blade would not instantamouely

become that associated with each velocity vector of the distorted

region ae the blade passes through the dietortion, for the purpose of

our analysis the aeexmtion that it does will bo suffioient. This

aaexmption allows the Velocity dingen associated with a point in the

diatortod region (dashed lines) to be superimosed on the volocity

dingen for any point in the undistorted region (solid lines), es shown

in Figure 2. This euperpoeition method is used in the analysis of

the three repreeentative inlet·-stage velocity diagnose shown A

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CONFIDEN‘I‘IAI• {

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Figure 3. The analysis eas made on the basic of incompreseihle flow

with the following aseueptiona:

1. The undistorted and dietorted floss enter the roter with the

same absolute direction.

2. The static pressure of the distorted.and udistorted flow ie

equal at the inlet and alao atrthe exit of the roter.

3. The increase of blade eagle of attack in the diatorted flow is

not eufficient to cause blade stell.

h. Th distorted flow is turnd in the rctor pasaage to the same

exit direction, relative to th roter, ae the undist¤rted.flow

· 1.0) .Figure 3(a) ia the velooity diegram of a rotor alone with an

undistortedeflow inlet-air angle of M50 {Bla). Both the diatorted and

undistorted Ilona enter te roter exially. Since the blade ahead ie

constant, the extremities of th inlet relative·velocity vectore of

the te floes lie along a line parallel to the inlet absclute~velocit

vectore„ The inlet reletive—velocity vector of the diatorted flow,

compered with that of the uudistoted flow, has a amaller magnitude,

poducee a larger inlet—air eagle (ßlä}, and therefore a greater angle

of attack fßlä — g) to the roter blade. ündr aeaumption L, the tec

floes exit relative to the rotor in the came direction. The equality

of static pressure (aseumption 2) end the difference in megnltade

between the inlet relative velocitiee require that the agnitude of

the exit relative velocity be less for the distorted flow. because

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Undietortod flowI Q-/ Bistorted flow3 / @„. W ,/ 6 "· .

WR *7 7*U. ‘·r ·· FZ Vga

I%<·——· L1‘-·-——-····-F;

U >}·<:AVt.

(a) Rotor alone, F]-H ·•· hS° in undistorted flow.„ R

\/6* MV,ll/" „« ° ‘

U,,,,,..,_.,..,., —U/" .V U U V U ,U7’3’ P*<***7********U7./U ——————-————··~- AV,/ (1,) Rgtgy with guide vane gl • 3g° and P1-R

• 60° in undistorted flow.(Hm * 61) " 9U°.

„ / / \§\I

Q- „ V, Vz\VIE.; .., ,,., .., ,., U..,.. ,..7, ,,,,, U., U,,..U .$U e U V|”{’3””_“"l U‘

*‘ ”U****** 7 *>·I·<*********—‘AV_g ‘* ·(e) Rotor alone, R13 - 6h° in undistorted flow. (gz}, + gz) • 9Q°,

Figéufc g}.- Velocity ,i,Lo.g#;1*:mn.=:„

:fm@„lyz6·t.lCONFIDENTIAL

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the static pressure: are equal, the difference in tctel pessure

between the tue I1¤«·reg1¤¤e on abaelute coordinetea is proportional

to the ditfereneee between the square: of their absolute velocitiea.

Fer this diagrem (Figure 3(a)), the diatertion has been redueed

epproximetely SO percent by the reter.

Figure 3(b) ie te veloiuy diegraa of a guide—vane·rotor combir

nation. The guide vane turns the flow 30° in the direction of roter

rotatien and the rotationel velocity is auch that the udistortedrflow

inlet·air angle to the roter Qßla) is 6U°• Since the included eagle

between the inlet flow directioue on the absolute and relative frames

cf reference ia 90° (ßlR + $1 • 90°), the inlet relative-Velocity

vector ef the undistorted flcu is perpendiculer te the line aleng which

lie the extreaitiee of the inlet relative·f10¤ vectera (VIE) of both

flow;. Theretbre, the inlet relative-flow vectore of both fluws will

be approximetely the same length ter diatortiene which de net preduee

a large change in the relative i¤1et»air angle. A change of 8° in the

inlet—air eagle, due to e aistortiou, will result in a difference in

relative elocity of 1 perceut. The static preeeures of these two

streame are equal; therefore, the total preesues relative te the roter

are •quel„ ßeth flews are turned to the same relative exit direction

and, because ef the required equeliey ef static pressure, the vectore

are ceineident. Since the rctatienal speed ie conetent the vectore

are also coincident in the absolute frame ef referen¤e,and, therefore,

the exit total preaeures are the sam. For this diagram, under the

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usmptions made, the diswrtiou would ba alimiuated by the first stage.

It is mtod that a aipificmt parameter far t-hs slimiuatioxz at the

distortion in the first stage of a. comrsasor is the included angla

between tkm relative and absolute flow diractiaxxa eutaring the rate?.

Au included augla of 90° between the relative and, absolute £'1o1r·

diractious is also significant when it cccura at the exit uf the rotor

(as evidauccd by Figure 3(c)). This valocity diayam is for a mtoralone with am u¤diatortod~£1ow i.¤lat·—air axxgla (gala) ot 6h°• Theaualysiß ot the fluw antaring the rotor for this diayam is the sam

as that for tba diagram of Figure 3(a)„ Tha turniug angla has been

selected ac that the axxgla between the relative a¤dab¤o1.u*bs flow

dirnct„i·>=¤ leaving the rotcr is 90° ($21% + 332-

90°)„ Thus, with the

uns rasaoning being used as in Figure 3(b), the absolute velecitias in

the distortad and in the undiatortod flow regions am appraximtaly

equal. Because cf uniform static prsaauxw far tha two flous, the totalpressuraa of the flowa ars equal. Tha difference in tha absolute flowangla car: ba ractifiud by the autor und the diatortipn will bs alimi-

natsd by the first stage.

Frama the valocity di•p·ams„ it can alac ba seem that thé deficit in

total praaswa batavaan the distortad and undiatortsd flo! is raducad

bacauaa the dismrtcd flow ia ansrgizad by the rator than ia the

undiatorted flcm. This ia manifastad by the larger change in tangantial

CO1‘ä*IHElN“1'lAL

ccnrxnsmzit..17 ..

Velocity across the roter for the diatorted flow. By using the mell-

knovn equation for the energy added by the roter

**2 * H1 " U2Vt,2 " “1V«.,1 (17

and the essmptions used for the velocity·diegran analysis, the dii‘fer··-

ence between the total pressures of any point in the xmdietorted flow

region and a point in the cliatorted flow region after pessing through

the roter can be expressed in terms of the flow engles. The resulting

equation, the derivation of which ia given in the appendix, for

incompreesihle flow is

, cos $31cosWhen

the zqsstream totabpreesure defioit and the Velocity dingen for

the undistorted flow are known, the downstresm total·-pressure deficit

can he deternined by using this eqaation.

äéquation (2) verifies the analysis of the velocity diagranm It

can he seen that if either or both of the included angles ($,1 + hm)

and ($2 + $2,,) is 9CJ°, the total·p1·essure deflcit between the distorted

and undistorted flowe will be eliminated. lf one of the inctluded eagle:

is geater than 90°, the total-pressure deficit will he negative. The

roter, therefore, more than made up the total pressure needed to reise

the dietorted—flow total pressure to that cf the undistorted Flos'. ItE

ie interesting to note that if both of the included angles are greater

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than 9<3·°_, the deficit will mt ba completely alimiuatach wasn the

valocity diagram has neithar of the included angles equal tu 9G°, the

dacreaae in the tulat total-prasauo distortion acrcsa to rutordapanda not enly on the maguitun of the inclusd auglas at ta antranca

and exit of thn roter buß alsc en the rnlntiva magnituda cf th• absolute

ad relative flow anglss at th antranca and at the exit; that is, the

larger the ratios of El- and Egg, the greater will be the dcvaaaaha $2in the disturtiou for given included auglas. Tha inlat toal~pra6aura

diatortiau could increase acrcsa the ratcr if the included angles ware

very small, and if $1 und wars much amallar nhau ßlä and 92,

r•sp6ctiv61y. Tha analysis has been given in terms of tha flow anglas

of the Velocity diagra¤„ äouevar, the vwlccity dagram is the ami

result cf a co¤prassor·stag¤ dsaign, and an analysis in terms af the

design paramstars, flow coefticieut (¢), and leading (zurniug angia)uuuld be of mre interest to the designer. Conaidariug the canclusions

ot the analysis with respect to these paramsters, it is £¤und_that for

an included axxgle (53R + {3) of 90° the flcw coafficiemt (:1:) raachsa anmaximum nf 0.5 when ßä ~ 3 - hS°. Tha flow coafficiant would have tobe lass than Q.5 fer an included angls to 6 graatar than 9G°„ Eheman included angla is 90°, there is ne apparsnm influence of loading cn

the amount cf distortion eliainstion since ths §§§~§§ä term ofaquation (2), which incraasaa as loading (tuning angla} incraasas,

has no influence- However, for inuludsd anglas athar than 90°, buth

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IGON3¤‘IBE;N’IIAL

I·· 19 ·· I

the flow coefficient and loading influence the amount of distortion

eliminationn The entering flow coefficient {el) in conjunction with

the goide··vane exit angle ({31) estahlishes the entering included eagle, I

The exiting flow coefficient Wg) in conjunction with the loading(tunning angle) det-ermines the dosnstream included angle. Since

included singles approaching 90° are dssired, the flow coeffsicientshouldbe

kept in the vicinity of 0.5. For given values of flow coaffioientsg

since gal and loading (tunning eagle) establieh the values of the

and terms, respectively, of ecquation (2), the guide·-Ä

vans tunning should be high and the loading low.Iim independent analytical analysis concerned with radisl I

äatisyrmxnetric) distortions was conducted in reference 8. In this

anelqyeis, it was also recognized that more energy is added by the

Iroter te the distorted flow region than to the undistorted flow regiom

As in the analysis of this thesie, an equation was derived for sister-I

mining the t;ntal·pressu1·e difference between the undialtorted and dis···tcrted flow regions after the floss have passed through the rotoru.

In reference 8,, the nmdistorted flow is considered to pass through theI

roter at e given radios and the distorted flow to follow at the same Iradius or to pass concurrently st a radios of close proximity whereas

in this theeis, the distorted and undistorted floss which are dieplaced I

circumfex·ent„islly are considered to pass concurrently thzrough the roterI

at the same radiua„ The two coneideretions are different wage ofZ

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Cf)2JF'II3F?—3TIAL• •

0Xp1'988i!lg ÜIG BQEBG cO!1CBpt amd Ü0 8QYJ&‘biO!‘13 of Ü56 two äliäélyßüß äfü

identitias. In reference 8, the equation was plotmd and the sameconclusiena were obtained as in thin thesia. 2I

I

II

VCGd’FIBI§.*¥‘1‘Iß„1.V.

§$X?E;&.I¥e€?£iTßl„ '䑧e$T:Z‘»

In order to check the results of the analysis of the velocitydisg·e.:;¤.s, a circuxafezential total-pressure distortion, produced at theentranoe of a conpressor stage by inurting a 1/h—·inch ediameter Mdperpendicslar to the exis of rotation, was measured upstream end down-

stresza of the roter.The velocity diagram analysis considered the flow at a given blade

element only, therefore a roter which has que.si-man-dizacnsional flowess selected for the tests. 'Phe roter in its original configasrction

was tested without a guide vans (rufe 9) ; however, #1 guide rene isrequired to produce an included angle of 90° st the entrsnce to theroter. gather than desigx a guide vme for the roter, an existinguntactsted blade which could he set tc produce a 9¤° included angle et

a given rsdius was used. The mean räine of the roter was selectedfor this condition.

Apperatua

A schematic dingen of the 28·—inch test coamessor is mesented in

Figure h. Tin flow enters from the atmosphere through a honeycoebstreightener and three screens. an wtrmce cone with a contrection

ratio of 13:1 is used to scee1m•ate the flcw into the test section. theroter discharges through an emulm• diftuser. Eiownstream of the annuler

diffuser the flow is turned outwm·d tmougdx a rßial diffuser which cam

he mjusted to decream or increase we exit area end thus regulete the {

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flow rate. The drive ie e 75·borsepower direct—cm·rent meter cperable0 to 21:00 rpm. Figure S is e photoyaph of the roter used in this

investigation. Its performance is given in reference 9. The roterbleaies were designed so that the exit tsngentiel velocity was insersely3:·rc;.>erticnel tc the rsdius (free vortex condition} and hw ;aedi.n:e-·

shirt. 55- (cz :119)].0 airfoil sections. The following table pre·~o

santa the design details:

Station Section “d*{1* gl1¥<‘,d E2€1,d lid, m’?;uS’

dag dag deg deg de; "Sieb 65-(l7A10)].O 16.0 26.0 hd.? 22.9 32.9 1.00 10.91rem 65-(l2»'11O)1G 12.5 18.8 52.5 33.7 hab 1.::s 12.1.1Tip 65-·(8.5;1 )lO 10.0 13.8 55.6 hl.8 2;5°.é 1..00 13.91

The sirfei]. sections were foreed by cembining the dsc e 65+010 basicthiclmeee distribution, reference 10, with cembered mean lines. Thement ef amber is expreseed as the desiga lift coefficient, cz , in

etenths for the isolated eirfcil. am indioates that the nee: lineprodsces uniform chordwiee normal force loading;. The blade cherd atthe man radiue was 3.0 inchee. The roter bladss were attached ts thehub with threeded blade sh=mI<:e end lock nnte to alles changes in thebledewsettiing smile to be made. The geide vans had a ccnetant

Ö$;··$3¢"31"i€£$.§ airfcil section with zero twist from hub to tie. The

coznsxgmtrz :11,

CONFIDENTIAL... gs ..

chord and solidity at the mean radios were 2.5 inches and 1.0,

respectively. nach blade was attached to the outer casing with a

single screw allowing variatlons in b1ads·-setting angle to be made.

Instrmentation

The aaasurlng stations are shown in Figure ls. Figure 6 shoes the

instrumentation at each station. The oircumferential location of the

rod wake upstream of the roter (station 1) relative to its location at

station 1 depends on the amount and the direction the flow is turnedby the guide vanes. The circumferential location of the wake downstreazs

of the roter (station 2) relative to its location at station 1 depends

not only on its location at station l but also on the amount the floe

is turned by the roter which in turn depends on the flow rate, Since

the instruments are fixed at the arial and circumferential locations

shown in Figure 6 (they are free to nova along and rotate about their

sten axes only), the rod has to be posltioned ciroumferentially at

station 1 for sach flow condition. For this purpose, several rod

ports are epaced circusferentially at station 1. A prism-type probe

capable of senslng static and total pressure and flow direction,

Figure 7 and reference ll, eas used to deteralne dynamic pressure atstation 1, A 26—tube total—pressure rake, Figure B, was used to

asaenre the red wake and a prisvtyps probe was used to measures dynamic

pressure and flow direction upstream of the roter, station l. A 25-tube

shielded total-pressure rake, Figure 9, eas used to measuro the rod wake

CONFIDENPIAL

CONFIDENTIAL

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CONFIDENTIAL

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CONFIDENTIAL

GOIGFIBXNEIAL• 3;) ...

and a priszvtype probe was used to measure the dynamic pressure and

flow direction downstream of the roter, station 2. The tubes of the

dovmstream rake were shielded and inclined bO° counterclockwise from

the axial direction in order to make the rake ineensitive to changes

in the exit·-flow angle and to provide masureaents an eqml die·te;o;·e

behind the roter trailing edge. All neasursnents were zetde st the

mean radius.

Test Program and Procedure

Three rotor·—alone and two rotor·gui<3e·vane configurations at a

solidity of 1.0 were used to produce various velocity diagmms. For

the three rotor·—alone con£ig;ux·ationa the roter bledee sera set et

design eagle of attack when the air inlet eagle (sm) at the mean

radios is l;S°, 52.5°, and 60°; that. is, hlade~sett1ng angles at the

mean radios of (td ··· 7•S°}, Ed ··• h€J°, ami (Ed + 7.5%, rsepecti.=re1§.e.

For both ef the rotor·-guide—vane configz¤·a·tions, the roterbladeset

for design angle of attack when the air inlet angle (pm) ist ~:C—<iö°

at the mean radios and the guide vane eas set to turn the flow

§$·;:°thedirection of roter rotation and also 2S° in the opposite direction.

Severel throttle settings were used tor each configxmation to provide

comparisons at various angles of attack. The roter speed for all tests

was 2,090 rpm. Por each test, the rod eas first positioned oircum··terentially so that its wake would pass over the upstream measuring

rake (station l), In order to completely define the wake, pressure

CONFIDENTIAL

s — 31 -readings were recordsd with and without the rod in position, With the

instruments at station 1 located close to the outer casing, to prevent

interference, the red was positioned circxxmferentially so that its wake

passed over the downstream measuring rake (station 2) and pressure

measurements were recorded with end without the red in place. In order

to insure that the dosnstream raks meaeured the complete clrcumferential

extent of the red wake, xneaauremnte were made with the red in several

circxxmferentisl locations, approxiaatcly l inch apart. All pressures

were measured by a mu1tiple··tube alcohol manometer board and were

recorded simultaneously by photographing the msnometerm

The roter speed was kept within 25 rpm using a tachonetsr end a

strobotac; the static and total·-pressure meseurements ars considered

to be accurste within il/2 percent of the dynamic pressure and the

measured angles are considered to be accurate within 2*-1/2°„ im the

basis of these testing accuracies the wake plate are considered to be

correct within. -Y-1.0 percent.

Presentation of Data

All of the wakes are plotted es the ratio of the difference between

the total, pressure of the undistcrted flow and a point in the distorted

flow to the dynamic pressure at station 1 ae a function of circxm-

ferentlal distance measured from the center of the wake, Because of

mixing lossee, the integrated totabpressure deficit between the wake

and the undietorted flow would increase ss the wake mrred downstreamseasuroments of the rodwake in a straight duct show that, between

GONFIDENTIAL

\CONFIDENTIAL

-32•

meaeuring position: correepcnding to those in the test (5*l/h inches

an 11-1/h inches dcwnstream of the red), the integrated totslepreseure

deficit would increaee by h.0 pereent. Since this change is so small

and since the roter ie expected to deereaae the integrated total-

preeeure deficit by 30 to 100 percent, comparison: across the roter

based on ää will euffice for this theeie„ The integrated deficit

will differ at the leading edge and at the trailing edge of the blade

from those at th upatream ad dcunetreem meesuring etations,

reapectively; however, the difference: would be less than h„0 percent

and can be considered in¤igni£icant„

CONFIDENTIAL

Cohfläz

E..gg ...

VI, IIS·‘‘’‘ US:·3IiÜ>h

Figure 10 presents the rod weae meeaured upstreaa and downstream

of the rctor, together with the domstze:·;m wake astiaeted using eaaetion

(2), for the five oonfigurations at aovzmxieetely design angle ofattack. Tha downstreem wakes were meesured on the rake with the zod in

several ciromuferential positions, different symbol is used

forredposition. The test points, both upetraam end downstreem, are located

with respect to the center of the wake, plots are arrenge;1 from the

too of the figure in the order of incxeasing wake elimination, based onthe ratio of the area under the estimated downetream curve to the area

under the meesured upstream curve. The peroentages of eetinated wake

elimination in the order of px•eeentat.ion are 39,3,, 39.5, 57,7, 353..5,and lie) (Figures 10(a) to 10(e)), respeetively. For al}. confi.gurati.ons,the xeeasured wakes decresse across the roter and the percentagee of

zaeasured wake olimination, in the order presented in Figure 15}, are

6h.h, 57.0, 77.0, 96.7, and 61;.9, respeotively. The rotorelirainatedgreater

portion of the wake than was estimated, with one exception; forthe rotor·~alone oonfiguratime, the trend of incrsasing wake eliminationfollows that estimated, The reason for the difference between the

estimated and mea.szu·ed percentage of elimination will be explainod

subsequently. For the rotor··guide~vas1e oonfigurations (ügures l·;>(b;

and 1<.;>(e}), coneiderable varietion between the wakes meaewed for the

several ciroxmferential positions of tho red is evident. Some of the

variation may be due to the change of circwxferential position of the

L

CONFIDENTIAL

I j ,_ ,,_ ,1 ,,1 1f @52 111

- 111111 muwnstream cst1rr1a1tw 1 1 10__I , 1 1 1

11 J1, f , 1

•’~ä "" ___ E ·=- 1

I1,V1 ,, ,; ,,1 ,11 11 1 1 2 111 1 1 1 *1 1 1 11

,4 Q 1L1 1 1 · 1 1 1 11‘ ‘ 1 I I 1 11 1 1 J1

„, PlI11 1 11 1 1 1 I 1 1 11 , 1, 1

I 1 I ,1*/ {:;,1 mxlzw 16:11:% gmde vane;~= 11 ,_ I

„_ « '

@1.1 -1-• ff ,1 , ,1 1 1 II il1 1 1 1 1

1 1 1 I

" - 11,1 1 1 , 1 .é.i , ,

1ca

<1> 3 I ,, 91 Plk 15211 @21 1 I 1 1 1 1 1 1 1

., 1 111 ;1 1 1 „ 1 1 Q ,101 ;„ Q1

1 1 1 11 1 11 1 11 111„‘

1 1 11ig1 zlktälälß

11“° 1 1 1:,,1Q1.1; 1,, 1 111: *111 g

1 1 1 1 =’l1 P2 1 §E2 ,3 11 11111411111

1 ‘I I 1 Ä_ Ä T11 I I 1 1 ‘1

1 1 1 1.§,,,1§;,;1 äö1 I 1 1 11g-(fi) Fi01;01" alome;1

11 1 •• 1

11 1* id °1" 7* · 111 ,· r I 11 1 1 11 1 1 1 II1 1_ 114

@1 11 1 1 1 11 1 1 1_,• 1111 1 1 I @1 11 1

1 1 1 W 1 1 1• n·11 ~‘ »-1 1il

L'

1' 1 1 1 f 1 11 1 1

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1 1 gd3 ,, ,1, 1_, 1 1 1 1 1UI 1 11 1 11, I

1 1 '1111 1 * 1 1 1I11— 1— 1 ,, 11,,, _I

-3 -1 Q 11 v— 1:1 1 f

‘ 1 gemhgr gfim.

111*1, „ 1 _ 1 1 ., ~• 11 , .1.1,, 1 _ _ . 1 1{E

dllil wakcésvnivß 1"

¤‘ 1 •·' ? 111 1 ,1.114 1, "¤ • ,„ •

.1,.,CONFIDENTIAL

¤·— 35rradwake relative to the guide—vane slades, It should he noted that the

k

estiaated downstream wskee ware caloulated for these tests essueing that

the straamlines enter and lslve the rotorszt the sam radios, whereae

the tests sie‘··.three dimonsional, (äquation (2)3applies to thrse—

diasasiooal flow if the streamline path ishnowu.) The

rotor—aloaooafigarstionswould be cleaer to twoesimsnsional flow than the rotor—

euide~w¤re configurations, because the roter was designed for two«

diensional flow without a guide ven, and the guide vans was netdesigned for use with this roter, The sismetching of the roter and

yuide vans leads ta more praounced radial flow shifts which.alter the a

shape of the wake across the roter coneiderably es manifested in the

dawnstream curves. For the rotor~alone configurations(Figureslife},

and 1h(d)}, the three—dimensionel effects are small, as evidsneed

at the extremitios of the downstream wakes, and the wakos measures atthe several circumfsrential positions ocinside.

Fiaure ll presents plate for the roter als at designhlade~settingangle

and angles of attack of Gd · é,8°, dd and Gd * 7.S°. Themeasured wake is redueed across the roter for all angles of attack and

followa the same trad es that estimated with respect to increasino the

persentaga of Keks elimination with increasing_a¤gle of attack. The

*

htrh snr1e·of~attack plot (Figure ll(c);, shows differences between

wake aasurcents at the various circsaferential pasitions and shap l

eltsration of the wakes across the roter similar to those of ‘iwure lß(e;„

Since the redial flow shifts at this anale of attack are more pronounced

than at design eagle of attack, Figure 1l(c} provides more evidence that

Cßhslhähflat

c0NF1DENT1AL

'll :Y A I A I A A A A A AA A A AQ AA :A A A A I A A: I

LA I * Y Y I I I I

Upstream meaarrz-:6“_ -Y II Y- YI IYL @12 I 322 I YeIL—- YYY -—- DOWUSIZIQELZB 8St»1!lI3.‘IBÖ Y Y-, Y AA O AA L‘ I I 0 Y . 32. 20.I1 I IY..„§§,YY Y Y YYYYYIYY TYY Y; YYY Y Y___Y_YY Y ___YI

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1 Y Y YYI YY Y Y Y Y YYYA0

Y Y . YAY Y YY IYY __IYYY YY I Y, YYYYYAYY Y_Y_

AI• Y I I.] I IYII : “' Y! I I I I I IY i Y Y Y L 2 lg) Y Y I I L YI I 'Y: Y 2 I . ..I 3I : Y H I I I

_·l I __ Y YY YYY YI Y_YY Y Y Y Y _ YY Y Y Y Y Y Y YY YYYY _Y YY__Y_ _ Y I: YY YYY_Y“Y_YY_YY Y_I

G. ·¤=€ Y YY YY Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y YY YII IIIIIIIIIIY1;L

I I Y : Y Y ^— YYYYIYY YY YY Y I IE Y I Y I 30°S2.3°33•0°3l.3 Y:3 •2 AA A A AAA ‘A A U

JA A AA AAA _' AA AAA— AAAA A AA

T} Y— E

N YIY A

/ Y Y Y YIY Y YY YY Y _YY WYYY YY Y IY A YYYY Y Y *Y IYI IIIIIIIIQ1I I [ I — = , I I IY Y I I

?:' ”—IrYI Al: Y A ‘ A I I Y II _Y YY Y Y Y YY

Y * : ·· I Al Y I Y Y

EI Y YY: YY YII,.1

Y YYI YYY YY YIY YYYY Y YY Y Y Y Y Y Y Y Y-Y—YY — - — ~ ~—--- - -- ——-- --- -

I I I I AI I I Y

1 Y YY Y Y Y Y Y Y . S Y { YY YYY YYLYL YL Y YYYYY I- YIs Y Y I I Y

A AY Y

‘g

AY Y

AI ^\ Y

I Y Y Y Y Y Y YI

ri-‘Ä_ ‘

Q Y _ _AY °;Y Y _AY.v ‘ Y_YYYY_YY” Y• Y I Y • YY YY Y_ I

13 I Q" Y VQVY Y Y Y [ Q I Y Y Y Y2 A I 4. Y I : Y_ _ Y _ Y _ _ Y YY YY Y _ Y Y YY YY Y AY YY Y YY YYY.YY Y Y Y.I YIYYYYY Y. YIIIII-3

-2 -1 0 1 2 3 IICircumferential distance measured from center cf wake, in. Y

Y Y _ Y Y ?ITI>YE“°i"?’I1.- ci :ti:e„;;Y11;r@d 11:1d wel»<;ee

KLLQE IW? TYA €AYYII° I' QT EEYICYIKLEÜ

Z-°etJGIECC Ellfltglüii :;Y?Z° ett:1IY:E—I:.I

CONFIDENIIIIALL

CzZ}N;é—=I„B23E%l‘I 1**.1,

... 37 ..

the difference between the wrzkes ezeesux~ed at the several ciz*eumferen·t3a;1l

positicne and the shape alteratien ef the wake :=·cx~ose the xetor 131

F‘i;i:u1·e l0(e}- are e result ef reeinl flew ehif‘te.

Ccneidering the rotox···al0r1e plate {since they ers cleser te t.ee—-

dzhuensionel flow} in Fiaguxss lk end ll, rirt is nnted that, since the

meeeured wake eliminstion follm-rs the tjxeated trend, the 3.

results verify the cezxcluslen ef the thcsretical analysis; that ls, the

degthse of distortien eliminatisn Sie e faectäon of the magmitzxie of the

anggles ef the velccity diagtre.m• C?entmr;~r ts the pz¤edi<:t3.en ef the

velecitwdiagram analysis, the ve1.oe*¥.ty d;I.r:„jrs1.z with ans inelsded anale

epprostixaetely 9·;}° and the other slifhtlgv 1a:·g5s2· then 951G ;iZ>ai3.ed ts

e1im:Lnate the distortisn completely hecacsre ef ti*:ree—d3.z;:er¤sien:+l eizectag

hewver, the three roter-alone tests sf FԤ.;;x.s*e 1;;* previde some prost

that a 9<>° included angle may be ceti;-run ier elzhainating -*1 d5.stort5.sn

across a stage. For these three vel··¤«2§.t;=# Magggrzsus, value ef the

bracketed tem ef squaticn {2), excled·3.ngr the exit incltxled-am*rle tem,

cos(§?-2 + 32%}, had values of 1.31, ;>,‘f9$, und ~-"E,,9h fer E·"£;;;ux·es lTé{a},

and lälajdz, respectively. These values zepmsexzt the rette ez? the

:i.nteg;x·eted estimted dewnstxteaatz wette te tm integrated upstzeam nete,

The of wake eltaimtion for the ti-rse ·ÄiE3;_{I°§tZY18 are thenezfere

perrent, 2,,2 percent, and 6,1 wereeht. The d5.f„L‘erem:es between the

three COI3l}l§„@}§LXI‘<itlOIlS are small, W¥’1€3I’€?}5‘i£} estizmted vxzlnee, iszcltaiizaqig

the exit i„nc3.zxicd«angle tem, are 3}*.3 gewusst, 57.7 percent, am

$3-;.,5wereeet.?he larger differeneee bstseezs the three C0ll£ll,§Qül“”%-Üiüxl-S maxi-

cate that the predom:§.mnt tem is the included eagle. The eaaesered7t

C«1i»2;‘FI rtl L

Ci>m5‘I2i1;;2‘:?I;äL...

gg ..

parcaxxtaggas of wake slimirxaticm far the thma diagmm, 61,;,1;, 77•iÄ?, cmd96.7 for exit included wlw of SIL.1°, 6h,3°, mad ?9.ü°, 1·6s_;>a¤tiw;3,y,hmm diffaremcas between them ot the 88136 order as those batwaazx themstimataci values; therefore, the advantage of the exit irxcludad mnggileatöäärßäching 9-09 is avidaxxh

As nom:} pmviously, the masmwd mlm was mduccd gmamr gmmmtthan that estimated; therefore, tm wake: was emrgizadtuaxtantthm calcv.lat6d„ A x·6app¤·a1¤a1 ot tha initial assmzptiona uponmich aqumzion (2) was based shows that, in omartomark

input than astircatmd, aithar 6. ~:·6at„a1— diffusion oacurs in tmwake (pgdistcrtiaxx pg) or the 1ow··~¤mz·gg;y air axparianoes a gmamrtumirzg than that asmmad 1,3 . The axiatarzcso of a diffamzmbetween ths static praasum in a wake cmd in the surrcmding flow 5.:6

contrzzry to axpezrianca; therefore, am lm·1~6nax·ggy air must have bwernovarbmmsd. Sinus the :·¤t„m· is subjactad te tha amgles attack in thewake for a shcrt period of tim, the st„atic~;21•6sau1·a field in the bladepassaga is dictatad by the xmdist-nrtad flow, Tha cantrifugal formarising from the turuing of the flow in the blade passaga ia rebtccl tothe mwass-u1·a gmdiant uomal to the direction of the stmamlim by

sa .. ,, ii.dr 1*

where- r is the mdius of of thestmamlim.becausethe relative valocity of the wake particlßa is lower than hixat¤£ the undistortsd flow, the wake rmrticlßs will not ba in eq1ü,11*m:~ium

with the surmuxxding praasxma field unless the mdius of cu1~vatu1~a uf tra

C<>HFIm£;m‘1AL

I

.. 39 ..

streemlizm ie mueller at all points, 12, The net result ie am

overtemihg of the distorted flow,

Ttmm are indicatione that this overtmming is true, es hl.ade~—

eettiag smgle or 1mdietorted~fl.ow angle of attack inoreaeee, the <15.£·—

ferenee between the relative velocitiee of the two flcms becomes emaller

and less difference in the redius of ourveture of the etreamlim ie

required to mefmtain aquilibrim. es bLacle·-setting engle (Figure 1116}

end ara<;¢1.e of attaek (Figure ll) ihemeeee, the meesured wake ie here

marl}; equal. to that estieatod, At this point, it should, be noted that

equatioh (2} would eetimate the downstreem wake more eccurately for inlet

flow dietortions which are of enough circwxfemntiel exteet te

alter the ste.ti„c~;>r·ees111·e field in the blade paeeage if the eagle ef

attack in the clietorted flow ie not large enough te cause blade stell,

IIIIII

Cäl!2F’IE}ä?’§¢’i‘I;*a1„{

II

, CONFIDENTIAL

*1Ni;>

*1 xi

H

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COPWIDENTIAL

2*11);;: ·; Ti IL.. hl ..

VII , C ‘“:j£·;£;Zg.;;.;I‘i=?£E3

;:reliminax·y theoretlcal and eacrerimental investigation of theeffect of velocity diagram praaeters on inlet t0ta1—7>ressz1r=;*: dietortionsthrough a ainglcwstage subsonic axial-·fl.oa ccmpresaor for 5.rxcon;t>ressiT>le

flow has been condncted. The wake of l/1;·inch—dia¤¤1eter rod, measwred

both upstreaxa and doanstream of roter, has been compared for varicustelocity dieggame. The measurod downstream wake was also compored withthe downetream wake estimated by using; derived equaticm subject te the

assuaotione that (a) the rmdistortad distorted flows enter the roter

with the same absolute ciirectien, {bl the static pressures of the tndis—l

to1·ta»i and dietorted flowe are equal at the inlet and also at the exit lof the roter, (cl the increase of blade eagle of attack in the distorted

{flew is not sufficierrt to cause blade etall, and (cl) the distorted low

is turned in the xotor oessage to the same exit direction, relative to

‘

the roter, aß the xmdiotorted flow, ßs result of thisinvaatigatiorz,the

following conclusions aremade:1.

Velocity diagams for which the included anale between

therelativeand absolute flow directions is 9¥)°, at either the inletorexitof the roter, are indicated to be ontimum for eliminating

inlettotalwreaeuredistortions across the first stage ef a compressor. gk f

flow eoefficient of 0.5 or lese is xerguired, but loading (turningFinale}has

nc angwarentinfluence.2,

Velocity dia;;·ams, with one of the included an glas greaterthan92**,

will increase the total pressure of the distortion beyond that of

CJ2éFID;Eä'i;‘IAL

.. hg ..

the IHTÖÄSÜOTÜBÖ total pressure. however, if both included angles are

greater then 9G°, the inlet total-·:;a·essu1··e dietortion will. not he case

pletely elininated, For these results, either or both theenteringexciting

flow coefficients must be less than 0.5.

3, then the velocity ciie:.:1·e.n has neither of the included asgles

equal ts $9€3°, the decrease in the inlet €Z.7€',€äl··$•Z"BS£111°B d5.stort·len across

the mter deperrls not enly on the .!Et&.T_§THl,Ö\Hll.€ of the inlet end exitincludedanghs,

but on the relatzlvo msgnitlxie of the absolute and r lative

flow angles et the inlet and et the exit. Beth flow coefficient and

loading influence the amoxmt ef distsztion eliminstion. Ehe flow

eoe£f·1-ct§.ent should net bo too than M5, the guide—·vane

e:«c:§t5.r1g angle should be hifhg ausl the l·;>e.ding should be low for the

greatest elirzination of distortion by the roter.1;. The experimental tests show that the derived equation will

eetimate the downstreae d5.sto1·t§.o1*z with reasonable aeouracy for inlet

t¤tn1·;·e·eeetu·e dietortion ·e·;»:#:ea·* far enouga circxmferentially to5

alter the statie—preesure field in the blade joassage, 1

The of the veloczity diag;m:u analysis given in the theetls

to determfme the veloci ty ehzlch would he most effective in

reducing an inlet tota.1~-pmssxxre räiatortion. This has been accompliehed

weder the given esswsptimma. however, the analysis of s. velocity die~·

et a single blade element does net give e coep].ete picture of the.flow through s comgvreesor stage. The mutual effects of the flow at all

redial etations depend on the pextieular desih of the comomseor stage g

C;bNI·*II>?;ä§Tä‘1;*.L 1

1

bg -

end are nwneroue and complex when the flow is uudietortevh Therefore,it appears that the eccompliekureazzt cu? 6; complete criterion for deeigéazixzggczompreseor stages which will elzlmirzete rm inlet totel·pres>;u:~e ;!5.eteri·.·€.<;ozwill develop pzimerily from experimental teste. F‘utur'> expez·i:aenta.tde¤shsmld include tests of compreaeor etagee having included nagglee ef $9

at ali blade elemente end teste where the flow ie m:lpreeaible„ ?‘efer—·enoe provides a eoepreesiole flow for düäfülüißß the amountof dietorbioa elimimatieu et e ggtvea blade element,

GONFII32;;$·2TI ·=.L

I L

.. hg ..

sta‘cic«;;¤*ess1¤·e field in the blade message, the derivad aäguetiou will

estixetvte the dometreem dietortioxz with reasonable accurecy.

3% 2@‘Ii‘¤§ä‘„Ieä'i‘IAL

Cf2E1'i’II1’ä2F”$’LAL

°" ""

IX . ACKh$Gä‘LEmuEr!IS

The author wishes to exproas his appraciation to the Rational

Advisory Comittee for Aerouautics for the opportunity to use material

in this thesis which was obtairxsd from a research project condmted, at

the Langley Laboratory.

COHFII>£zI*€TIAL

CONFIDIHTTIAL 2... [,7 ..

. 1äIBLIOGR.APZ—IY

1. Sterbentz, Eéilliam H.: factors ControllingAir··1‘nletSistortions.MCA SEE E56A30, 1956.

2. Selber, Curtis L., Sivo, Joseph H., md Jansen, Ezsnert T.: Effectsof Unequal Air-Flow Distribution From Twin Inlet Euete onPerformance of mx Axis}-F1o·¤r Turbo,jet Engine. HAGE $@:13, 1953;.

3. Fehn, Savid S., md Sivo, Joseph H.: Effect of Inlet Sistortionon Compressor Stall end Aeeeleretion Characteristics of a J65-E-3rarooget Engine. 1955.

2;. Eiercy, Thomas G., and Elmxn, John L.: Experimental Investigationof Methods of Improving Diffusor-Exit Total—Fress1:1·e zrofilee fora Side—Inlet äbdel at Esch Number 3.05. 2*4ACA RE? 1%:551*22:, 1955.5. Smith, Even 0., Breithewaite, H. 21., end Calvert, Ho·es1·d E.: Effectof '1n1et·Air·:’loe Distortions on Steedy-State Eerformmxce ofJ65-21··3 fmrbojet Engine. MCA an 2+:55109, 1956.6. Conrad, Hilliam, end Soboleeski, Adam E. : Investigation of

Effects of In1et~Air Velocity Dietortion on Performmzce ofTurbojet Engine. HACA. 922.* E5GGl1.7. Steffens, C., Jr., Throndson, L. H., md Happliu, C. H.: Gevelopmentof a Method for Correleting the Effect of Various Types ofCircumferential Zmflow Distortion on the Stall Gbm·aote1•iatice of

A>d.a1··F1ow Coamreseor Engines. Prett end Eeport Ho. ESA.Illßte8.

Smith, L. H., Jr.: Recovery Ratio — 1 Erasure of the Loss HecoveryPotential of Compressor Stegen. Ho. 56-A-206, A.S.t2.E.(Sresented et A.S.H.E:. Annual Theting, Her York, How:. 25630, 1956. )

9. Ashby, George C., Jr.: Comparison of Low-Speed Eotor and FassadeEerformmoe for MCA 65-—(C, Am)10 ConxpreseoruäladeoSections Over a Side Range ef Rotor Slode—Setting Angles atSoliditiee of 1.0 md 0.5. NACA L52;I13, 19521.

IJ:. Abbott, Ira H., Von Doenhoff, Albert , msi Stivers, Louis S., Jr.:S1 of Airfoil Data. SAC Sep. 822;, 192:5. (Supersedeema:ll.Schulze, Fßallsee 12., Ashley, George C., Jr., end Erwin, John E.:

Severo.1 Cozminstion Frohes for Surveying Static end Total eressnreand Flow Sirection. HACA TH 28%, 1952.cearmxmrrmt

CZSIIFIBIEQTE

AL.*LTI¤?§OF THE E<Ii;Eä.¥ATI<T§i*N ä~I§$’£’Ié%1TIE€G‘~ THFS AL-§>E’äfiS§3$§?%,1’IDI‘FFE?2§?Z’£~IC Tliä U?=¥DI3T£}E%?’??11 FILE; AZLEE A £„·‘£.‘>E?$T

I}! DISTCRTTEI} "i‘E·iE¥i F’LC#’i°?

EEAS HGTOR

The equeticm for the energ added by the mtor ia

E2 ·— gl • U2‘!t’2 ··· ?}l‘Jt’1 (Al)

isince u + Ä the eue1·g_•,r added by the roter can else be expeeseed esF1

2 1

defhxition u ¤• evt or using the perfect gas lau (P ¤ piäit)

u •pH

äbatituting in (A2) and aesumng imompmesible flow, (A2) become

Pv P2 " 1 —.“2‘“1'?;‘,;‘(Pz*$*1) <*·3»*Eiquetixxg (A1) md (A3) md z·em·rmging gives

P2 pl cv····· ······ U · U V ~ ····· - (A!p ° p P 2v*·•2 1 M1 Rp (P2 P1) ~ ’·)

CGLFIBENTIAL

c»€}>£F1hä2ä"TL2L

The tetabpreseure d:Lffer% between the zmdietorted flw and a

point in the distorted flow entering the roter ie e function of tte

difference in the squaree of the absolute velooitiee; therefore, the

verietion in total wessure betweax the two flow regions domstreen of

the roter will be determiued with respect to 21*72.Since U2 and gl ere censtmt for a given. velncity dingen,

ev end H ue constants, p ie constant for incowreesible 1.**lew,. $1 .,(pa ·- pl) is constmt under tion 2 of **AReL¥SIS,** p, p, etßl

md Ut 2 me the only variables with respect to U12/2 in eque·—I

tion (Ah), It crm be seen from Figure 3(b) that

. °' 2 _, j .—ein am pl {6:}

Vt,2 • U2 ·· Vfozä • U2 ··· VZR ein tag (tee;

Uxuisr assumptions 1 md 1; of ¤emLYSIS” ein S1 and ein gal? me

otmstmtß with respect to V172; therefore, the Velocity VQR

ie the only remeiuing variablm The velocity U23, in terms ef vlyäz,

een be obtained from the relative eethaley rise which is

‘ 2 2 2 ~ 2**2 · **1 fg2 pl)° 22FromFigure 3(b) it cen be sem that

2 2 2 2~„__~i2„2,—„2__; egUm • Val + vtqm ¤• Val • (tl vml) Val + *.1 2„?Vt,l + ftal

#.7,

subetitutiug vl? • 21212 + 22,12 and using equsticu (,1.5) we ebtem

vmz ·· 2:12 -·- 2Ul\]2 J2212/2 am pl + 26:12/2) Üaécj

Thea, subetituting equaticm (Abc) into equetion (A62:) ami resz·r2e1ging,

the velocity VZR in term of is es follcmsz

,2 _§_E_g ___·· 2..2 2211 {2 V1/2 ein 21 + 2(J1/2) Rp (p2 pl) (262)

Substitstixxg equation (Aöd) inte equstion (A.6a) results in

Bi!} V1 2

B1!}Commingequetious (M1), (A5) md (A6e) gives

__ __Q " Q "U2 U2 Sm ***22.d U2 2 V1 2 yg, (P2 21)

2 2 an •• VW}’•·

Ä2„l\[2 Jvl/2 sm pl Rp (pa pl) „r27,

Taking the derivartive of equetion (A?) with respect to 1*1*72 results in „

622 am 221) 1 212sm22 v v v vZR 1 22 1

Tmltiplying both sides of equstion (AB) by :161*72) md substituting

p dql •• @1 gives

1 ; (@1 as ¤111)(¤1 ¤¤= @1) _ @1 es @11 __ @1 ¤¤= @1 11112 1 VZRV1 V211 V1

V VEsaltiplying the epp¤·o;u·3.ets terms by or ..,%.2... end subetimtingVal Vaz

V V 1ess {% • -:::% md eos {BH results in the fellouing equatiorx:R

111***2 $31sfmvü2R Val 1

U Ucos {BZR sin ·· cos {$1 sin {31 (518}

I2 al

inSubstituting -@-- •-%-1-%-% + LEE in squstion (A10}, using; the i.der1ti·t;;

Va cos $3 cos ER

ees(ß cos B cos 911 ·~ ein ß sin 5*112, sed remwzsxgiug gives

111-, 1111 11 ß -1 1, °°°@12( 1 ggg {311% ggg {$2 I

COHFIB§§·ITIß1L

Ü

i }

This is tim equetiozri for tim tote1~p¤·eas1z2*e deficit between eny point in

tim undiaterted flow region end e point im the distorted flow efter the

flow has passed through the roter, If the upstresm tote}-pressure

deficit- md the velocity diegem for the mmdistorted flow is knows, the

dewrzstresm tota1-preesure deficit can be obtainem

COHI•’ID&’£ä*TI.AL

Ü

l CONFIDENTIAL

*INV”ESl*IGATI0N GF THE BFFECT OF VELOCITY DIAGRAM PARAMETERS ON

INLET TOTAL~PRESSUHE DISTORTIONS THHOUGH SImLE~STAGESUBSONIC AXIAL···FLOW GOMPRESSORS

By George C. Ashby, Jr.

ABSTRAGT

An analysis of several c¤mpx·essor-stage veloeity diagams was made

to determine the effect of the vslccity disgram paremeters on the

amount an inlet total-·pressure distortion will be reduced by the come

pressor stsge• The velccity diayam which is most effective in

eliminating an inlet tota1·press111·e distorticn within the cempresser

stage was determined. An equetion fer estimating the amount of dis—·

tortion eliminatich was derived fer incompressibls flow.

The results of the velecity disgrem analysis were verified experzir

meutslly by iutroducing a small disturbsnee (red wake) upstresm of a

lowspeed compressor stage.

GSMFIDENIIALÜ