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DISPLAY
HEAT-EXCHANGER SIMULATIONS BY MEANS OF PHOENICS
These examples make extensive use of the "neighbour"
technique, whereby the use of a special patch name
activates special calls in GROUND which are to be
included in GREX.

It will be useful to extend the series further, so as
to illustrate how two-phase flow can be handled on
tube and shell sides of a boiler, and to show also how
cooling-tower problems can be handled with the aid of
this technique.
ENDDIS
The cases dealt with so far are:-
2. Transient counterflow.
3. Transient counterflow
with allowance for the heat capacity of the metal.
5. Transient crossflow.
6. Transient crossflow.
with allowance for the heat capacity of the metal.
8. Transient baffled-shell-and-tube.
9. Transient baffled-shell-and-tube
with allowance for the heat capacity of the metal.
11. Transient two-phase baffled-shell-and-tube.
12. Transient two-phase baffled-shell-and-tube
with allowance for the heat capacity of the metal.

GROUP 1. Run title
TITLE
User-defined variables
T1IN = inlet temperature of shell fluid
T2IN = inlet temperature of tube fluid
FLO1 = mass-flow rate of shell fluid
FLO2 = mass-flow rate of tube fluid
COEF1 = heat-transfer coefficient on shell-fluid side
COEF2 = heat-transfer coefficient on tube-fluid side
COEF12 = overall heat-transfer coefficient.
Note that, for the sake of uniformity of nomenclature,
the first and second fluids are referred to as "shell"
and "tube" fluids respectively.

REAL(T1IN,T2IN,FLO1,FLO2,COEF1,COEF2,COEF12)
T1IN=1.0;T2IN=0.0;FLO1=0.1;FLO2=0.1;COEF1=0.1;COEF2=0.1
COEF12=1.0/(1.0/COEF1+1.0/COEF2)

GROUP 3. X-direction grid specification

The heat exchanger is a rectangular box, 1m high,
1m wide and 10m long.

GRDPWR(X,20,10.0,1.0)

GROUP 7. Variables stored, solved , named
SOLVE(H1,H2)
NAME(H1)=1STH;NAME(H2)=2NDH

The fact that the shell-side fluid does not have access
to the whole of the shell requires the specification of
"area porosities".
These are set to 0.5 in GROUP 11 below.

STORE(EPOR)

GROUP 8. Terms (in differential equations) & devices

The built-in source, convection and diffusion terms
are cut out for all variables.
TERMS(1STH,N,N,N,P,P,P);TERMS(2NDH,N,N,N,P,P,P)

GROUP 11. Initialization of variable or porosity fields
FIINIT(1STH)=T1IN;FIINIT(2NDH)=T2IN
FIINIT(EPOR)=0.5

GROUP 13. Boundary conditions and special sources

West boundary; shell fluid inlet ; 1 cell in west wall
PATCH(INLET1,CELL,1,1,1,1,1,1,1,1000)
COVAL(INLET1,1STH,FLO1,T1IN)

East boundary; tube fluid inlet; 1 cell in east wall
PATCH(INLET2,CELL,NX,NX,1,1,1,1,1,1000)
COVAL(INLET2,2NDH,FLO2,T2IN)

Note how the giving of special names to patches,
beginning NE (for neighbour), coupled with LOCNE in the
"value" location, produces sources which simulate along-
the-tube convection fluid-to-metal heat transfer etc,
by activating special calls to GROUND, the relevant
extract from which appears in an appendix to this file.

Flow of shell fluid
PATCH(NEW1,CELL,2,NX,1,1,1,1,1,1000)
COVAL(NEW1,1STH,FLO1,LOCNE)

Flow of tube fluid
PATCH(NEE1,CELL,1,NX-1,1,1,1,1,1,1000)
COVAL(NEE1,2NDH,FLO2,LOCNE)

Heat-exchange with tube fluid, throughout the exchanger.
PATCH(NEPLUS,VOLUME,1,NX,1,NY,1,NZ,1,1000)
COVAL(NEPLUS,1STH,COEF12,LOCNE)

Heat-exchange with shell fluid, throughout the exchanger.
PATCH(NEMINUS,VOLUME,1,NX,1,NY,1,NZ,1,1000)
COVAL(NEMINUS,2NDH,COEF12,LOCNE)

GROUP 15. Termination of sweeps
RESREF(1STH)=1.E-6*FLO1;RESREF(2NDH)=RESREF(1STH)
LSWEEP=50

GROUP 21. Print-out of variables
Print-out of porosities is suppressed.
OUTPUT(EPOR,N,N,N,N,N,N)
OUTPUT(1STH,N,N,Y,Y,Y,Y);OUTPUT(2NDH,N,N,Y,Y,Y,Y)

GROUP 22. Spot-value print-out
IXMON=NX/2;TSTSWP=LSWEEP/10

GROUP 23. Field print-out and plot control
NXPRIN=NX/5;IPLTL=LSWEEP;IPROF=1;ORSIZ=0.4;XZPR=T;NPLT=1
IPROF=3
PATCH(PROFILES,PROFIL,1,NX,1,1,1,1,1,1000)
PLOT(PROFILES,1STH,T2IN,T1IN);PLOT(PROFILES,2NDH,T2IN,T1IN)

GROUP 24. Dumps for restarts
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