Incorporation of Condensation HeatTransfer in a Flow Network Code

Miranda Anthony & Alok Majumdar

NASA/Marshall Space Flight Center

Huntsville, Alabama

https://ntrs.nasa.gov/search.jsp?R=20030000738 2020-04-04T22:54:00+00:00Z

Content

Introduction

Problem Description

Generalized Fluid System Simulation Program

Condensation Heat Transfer

Solid to Fluid Heat Transfer

Numerical Model Results

Conclusions

References & Acknowledgements

Introduction

Pure water is distilled from waste water in International

Space Station

Distillation assembly consists of evaporator, compressorand condenser

Vapor is periodically purged from the condenser to avoid

vapor accumulation

Purged vapor is condensed in a tube by coolant water prior

to entering purge pump

The paper presents a condensation model of purged vapor

in a tube

PA Distillation Assemblyi Demister

Stationary Bowl

(stationary)

Centrifuge

(rotates)

Feed Tube

(stationary)

Motor

LiquidLevel

Sensor

(stationary)

Brine Pickup Tube

(stationary)

Distillate Pickup Tube (hidden)

(stationary))orator

(rotates)

Condenser

(rotates)

Compressor

(rotating lobes

in stationary

housing)

PA Simplified ;,z ematicl

Wastewater Tank

Urine

from

Node 3

Product water

Assembly

Recycle Filter Tank Assy.

(accumulates & stores

brine for disposal)

Superheated

Water Vapor

Pinlet = 0.95 psia

Tinle t = 101 °F

Problem Description

Touter wall = 65°F

Saturated

_- Water Vapor

Poutlet = 0.5 psia

Inner Tube Diameter = 0.125 inch

Outer Tube Diameter = 1 inch

Length = 4 inches

Material is Titanium

Calculate the Quality and Heat Transfer Properties

of the Water as it Condenses in the Pipe

Model consists of 2 Boundary Nodes and 28 Internal Nodes

and Models Conduction through the Tube Wall

H2

Generalized Fluid System Simulation Program

02(GFSSP)

H 2 + 0 2 +N2

O

GFSSP calculates

pressure, temperature,and concentrations at

nodes and calculates

flow rates throughbranches.

N2

GFSSP

Finite Volume Method

Finite Volume Method is based on conservation principle

of Thermo-Fluid Dynamics

In Classical Thermodynamics we analyze a single controlvolume

In Finite Volume Method, flow domain is discretized into

multiple control volumes and a simultaneous analysis is

performed

Finite Volume Method can be classified into two

categories:

- Navier-Stokes Solution (Commonly known as CFD)

- Network Flow Solution (NFS)

GFSSP

Finite Volume Method

48 psia

D 45 psia

46 psia

Network Flow Solution (NFS)

SideWall I

Side Wall

SideWall

Side Wall

Side Wall

Side Wall

Top Wall Top Wall Top Wall Top Wall Top Wall Top Wall

Bottonl Wall Bottonl Wall Bottonl Wall Bottonl Wall Bottonl Wall Bottonl Wall

Navier-Stokes Solution (CFD)

Side Wall

Side Wall

Side Wall

Side Wall

Side Wall

Side Wall

GFSSP Process Flow Diagram

Preprocessor

Input Data

File

|

• Command line preprocessor

• Visual preprocessor

Solver & Property

Module

• Equation Generator

• Equation Solver

• Fluid Property Program

Output Data File

User Subroutines

...................................

New PhysicsT

• Time dependent

process

• non-linear boundary

conditions

• External source term

• Customized output

Coupling

p- Pressure

m - Flowrate

h - Enthalpy

c - Concentration

p- Density

of Thermodynamics &

PFluid mDynamic___

E1TOF p,hh

Iteration Cycle

Pm_

c

GFSSP Solution Scheme

SASS: Simultaneous Adjustmentwith Successive Substitution

Approach : Solve simultaneously

when equations are strongly

coupled and non-linear

Advantage:Superior

convergence characteristics with

affordable computer memory

Condensation Heat Transfer

10

ed

E

0.5

Vg, m/s

76

32

_ ,_13

| • • .

5 10

(T,- T.), K

, ,,. .......................± ....

/ Filmwise

I . I

5O 1O0 500

Heat transfer correlations

Akers, et al, 1959 - Annular Correlation

Boyko and Kruzhulin, 1967 - Annular Correlation

Chato, 1962 - Stratified Correlation

Soliman, et al, 1968 - Generalized Correlation

Chose Soliman correlation for its stability and generality

Annular Condensation Stratified Condensation

Soliman Correlation for Heat Transfer Coefficient for

Annular Flow Condensation

h=o.o3 prO. 5]L--Z, j

_/_'/ o _)°_4°_,_°/_//Fs : 0.04SReT°2|+_ x 1++s.7o/_' / (1 -- X)0470 X 133 -}- 8. ] --

Fm = 0.5/D___ [ _4 2(1 Jr

t az)L sw_ t p,; -#

, / ,,4/3

Jr. Pl )

¢ _1/3, / ,,5/3

x Jr. Pz )

F=O

Ff: Effect of two-phase friction

Fm: Effect of momentum changes in the flow

Fa: Effect of axial gravitational field on the wall shear stress

Inlet _[__Outlet

Solid-to-fluid heat transfer

Solid Node

InternalFluid Node

,, J Ts°lid -- Tcoolan t re(D--

BoundaryFluid Node

Fluid Branch

TQcondensation

Tsolid (r)

- h A (Tfluid-Tsolid)

1 m

Plot of Quality vs. Pipe Locationfor Selected Heat Transfer Correlations

a

0.95

0.9

0.85

0.8

0.75

0.7

0.65

0.6

0.55

0.5

+ Akers ................._'_..__ '\'_'--__......_ ......Boyko _ -

_._....Chato

S o lim an "_ _'_-_'&_'_

......"J///_z-..._..__

0

For Grid Size = 20 and R = 1

i i i i i i i

0.5 1 1.5 2 2.5 3 3.5

Distance (in)

2500

Heat Transfer Coefficient vs. Pipe LocationSoliman Correlation for Grid Size 40 and R Value 1

¢.)_=

O(.)

¢/)

}--

-r

2000

1500

1000

5OO

0 _, ,e,i i i i i i i

0.5 1 1.5 2 2.5 3 3.5

Distance (in)

4

Quality Comparison for Different Tube Grid Resolution

(Soliman Correlation)

>,

e=

O

0.95

0.9

0.85

0.8

0.75

0.7

+ 10 grid

....._...... 20 grid

30 grid

....._......40 grid

50 grid

0 0.5 1 1.5 2

Distance (in)

2.5 3 3.5 4

85

Outer Wall Temperature Comparison for Different Tube Grid Resolution

(Soliman Correlation)

84

83

82

_" 81

80

78

77

76

75

0

--e-- 10 grid

, , , , , , ,

0.5 1 1.5 2 2.5 3 3.5

Distance (in)

Conclusions

A condensation heat transfer model was

successfully incorporated in a general purposeflow network code

The numerical model considers solid-to-fluid heat

transfer

Soliman et al's correlation of condensation heat

transfer is recommended due to its generality and

stability

References & Acknowledgements

References:

1. Don Holder, "Urine Processor Assembly Condensate Issue",NASA/Marshall Space Flight Center, Environmental Control andLife Support System Group, August 31,2001, Huntsville, Alabama.

1. Rohsenow, W. M., Hartnett, J. P. and Cho, Y. I., "Handbook ofHeat Transfer"3 rd Edition, McGraw Hill, 1998

2. Soliman, M., Schuster, J. R. and Berenson, P. J., "A General HeatTransfer Correlation for Annular Flow Condensation", Journal ofHeat Transfer, ASME, May, 1968.

3. Majumdar, A. "Generalized Fluid System Simulation Program(GFSSP) Version 3.0" Sverdrup Technology Report No. MG-99-290, November, 1999.

Acknowledgement:

Authors would like to acknowledge Mr. Bruce Tiller and Mr.Richard Schunk of MSFC for their suggestions and comments