PHOTON USE
p;;;;;
up 1 0 0;vi 0.5 1 0.75
gr ou x 1;gr ou y 1;gr ou z 1
gr ou x m;gr ou y m;gr ou z m
gr ou x 1 y 1 2 z 2 2 col 2
gr ou x 6 y 1 2 z 7 7 col 2
gr ou z 4 x 1 4 y 1 3 col 6
gr ou z 6 x 2 5 y 1 3 col 6
ve y 2 sh
msg 3D SHELL-AND-TUBE HEAT EXCHANGER
msg --------------------------------
msg Velocity 1 phase:
msg Press Enter to continue
pause;vi 0 1 0
msg 3D SHELL-AND-TUBE HEAT EXCHANGER
msg --------------------------------
msg Temperature distribution 1 phase:
con 1sth y 2 sh;in 50
msg Press Enter to continue
pause
con off;red
msg 3D SHELL-AND-TUBE HEAT EXCHANGER
msg --------------------------------
msg Temperature distribution 2 phase:
con 2ndh y 2 sh;in 50
msg Press e to END
ENDUSE
GROUP 1. Run title
TEXT(3D SHELL-AND-TUBE HEAT EXCHANGER:110
DISPLAY
The heat exchanger considered has two baffles within
the shell and the tubes arranged in five passes.
The overall heat transfer coefficient depends on the
local velocity and is introduced by PLANT.
=====================
ENDDIS
REAL(T1IN,T2IN,FLO1,FLO2,COEF1,COEF2,COEF12)
Here 1 refers to the shell-side fluid and 2 to the tube-side fluid
The units are arbitrary
T1IN=1.0; T2IN=0.0 ! temperatures
FLO1=0.1; FLO2=0.1 ! flow rates
COEF1=0.1; COEF2=0.4 ! heat-transfer coefficients
COEF12=1.0/(1.0/COEF1+1.0/COEF2)
RG(1)=COEF12 ! overall coefficient, transmitted via RG(1)
REAL(RESCO);RESCO=1.E2 ! tube-bank flow-resistance coefficient
GROUP 3. X-direction grid specification
The heat exchanger is a rectangular box, 1m high,
1m wide and 4m long. A uniform 5*3*8 grid is used,
as was done by Patankar and Spalding in the first-ever
heat-exchanger simulation [ Afghan & Schluender (Eds),
'Heat Exchangers', Scripta Book Company, 1974].
The example is chosen only because of its historical interest;
for the 5-pass flow pattern does not make it a good heat
exchanger.
Only one half of the exchanger is included in the
calculation domain, because of symmetry.
The shell-side flow pattern, and the temperature fields of both
fluids, are 3D because the shell-fluid inlet and outlet do not
cover the whole dise area.
GRDPWR(X,5,1.0,1.0)
GROUP 4. Y-direction grid specification
GRDPWR(Y,3,0.5,1.0) ! half-width is 0.5 m
GROUP 5. Z-direction grid specification
GRDPWR(Z,8,4.0,1.0)
GROUP 7. Variables stored, solved & named
The shell-side fluid is a single-phase one, for which the
folowing five variables must be solved; only the enthalpy
needs to be computed for the tube-side fluid, because its
flow pattern is prescribed.
SOLVE(P1,U1,V1,W1,H1,H2)
NAME(H1)=1STH;NAME(H2)=2NDH ! names signify first- and second-
! fluid enthalpy
STORE(EPOR,NPOR,HPOR)
GROUP 8. Terms (in differential equations) & devices
The "diffusion" terms are cut out for all vaiables, and
the built-in sources for the enthalpies.
TERMS(U1,Y,Y,N,Y,Y,Y);TERMS(V1,Y,Y,N,Y,Y,Y)
TERMS(W1,Y,Y,N,Y,Y,Y);TERMS(1STH,N,Y,N,Y,Y,Y)
TERMS(2NDH,N,N,N,Y,N,N)
GROUP 11. Initialization of variable or porosity fields
FIINIT(W1)=FLO1;FIINIT(U1)=0.0;FIINIT(V1)=0.0
FIINIT(1STH)=T1IN;FIINIT(2NDH)=T2IN
FIINIT(EPOR)=0.5;FIINIT(NPOR)=0.5;FIINIT(HPOR)=0.5
GROUP 13. Boundary conditions and special sources
West boundary; shell fluid inlet ; 2 cells in west wall
PATCH(SHELLIN,CELL,1,1,2,3,2,2,1,1000) ! small patch in west wall
COVAL(SHELLIN,P1,FIXFLU,FLO1/2.0); COVAL(SHELLIN,1STH,ONLYMS,T1IN)
East boundary; shell fluid outlet; 2 cells in east wall
PATCH(SHELLOUT,EAST,NX,NX,2,3,NZ-1,NZ-1,1,1000) ! patch in east wall
COVAL(SHELLOUT,P1,FIXP,0.0)
High boundary, tube fluid inlet; 5 cells in high wall
PATCH(TUBEIN,CELL,1,1,1,NY,NZ,NZ,1,1000) ! IX=1; all IY; IZ=NZ
COVAL(TUBEIN,2NDH,FLO2/3.0,T2IN)
Note how the giving of special names to patches,
beginning NE (for neighbour), coupled with LOCNE (GRND8) in
the "value" location, produces sources which simulate along-
the-tube convection fluid-to-metal heat transfer etc,
by activating special calls to the built-in coding:
gxnepat.for
The flow pattern is:
---<--------------------------------------------
^
--------------------------------------------!
^
!--------------------------------------------
^
--------------------------------------------!
^
!--------------------------------------------<---
In the following COVALs, the /3.0 appears because there are
3 cells in the y-direction (NY=3)
Flow of tube fluid in first pass <---
PATCH(NEH1,CELL,1,1,1,NY,1,NZ-1,1,1000) ! IX=1; all IY; IZ=1,NZ
COVAL(NEH1,2NDH,FLO2/3.0,LOCNE) ! from higher-z neighbour
Flow of tube fluid in first bend ^
PATCH(NEW1,CELL,2,2,1,NY,1,1,1,1000) ! IX=2; all IY; IZ=1
COVAL(NEW1,2NDH,FLO2/3.0,LOCNE) ! from lower-x neighbour
Flow of tube fluid in second pass --->
PATCH(NEL1,CELL,2,2,1,NY,2,NZ,1,1000) ! IX=2; all IY; IZ=2,NZ
COVAL(NEL1,2NDH,FLO2/3.0,LOCNE) ! from lower-z neighbour
Flow of tube fluid in second bend ^
PATCH(NEW2,CELL,3,3,1,NY,NZ,NZ,1,1000) ! IX=3; all IY; IZ=NZ
COVAL(NEW2,2NDH,FLO2/3.0,LOCNE) ! from lower-x neighbour
Flow of tube fluid in third pass <---
PATCH(NEH2,CELL,3,3,1,NY,1,NZ-1,1,1000) ! IX=3; all IY; IZ=1,NZ-1
COVAL(NEH2,2NDH,FLO2/3.0,LOCNE) ! from higher-z neighbour
Flow of tube fluid in third bend ^
PATCH(NEW3,CELL,4,4,1,NY,1,1,1,1000) ! IX=4; all IY; IZ=1
COVAL(NEW3,2NDH,FLO2/3.0,LOCNE) ! from lower-x neighbour
Flow of tube fluid in fourth pass --->
PATCH(NEL2,CELL,4,4,1,NY,2,NZ,1,1000) ! IX=4; all IY; IZ=2,NZ
COVAL(NEL2,2NDH,FLO2/3.0,LOCNE) ! from lower-z neighbour
Flow of tube fluid in fourth bend ^
PATCH(NEW4,CELL,NX,NX,1,NY,NZ,NZ,1,1000) ! IX=5; all IY; IZ=NZ
COVAL(NEW4,2NDH,FLO2/3.0,LOCNE) ! from lower-x neighbour
Flow of tube fluid in fifth pass <---
PATCH(NEH3,CELL,NX,NX,1,NY,1,NZ-1,1,1000) ! IX=5; all IY; IZ=1,NZ-1
COVAL(NEH3,2NDH,FLO2/3.0,LOCNE) ! from higher-z neighbour
PLANTBEGIN
Heat-exchange with tube fluid, throughout the exchanger.
PATCH(HEX,VOLUME,1,NX,1,NY,1,NZ,1,1000)
CO=2.*(U1**2+V1**2+W1**2)**0.25
VAL=2NDH
COVAL(HEX,1STH,GRND,GRND)
Heat-exchange with shell fluid, throughout the exchanger.
CO=2.*(U1**2+W1**2+V1**2)**0.25
VAL=1STH
COVAL(HEX,2NDH,GRND,GRND)
PLANTEND
Baffle 1 at NZ=3
PATCH(BAFFLE1,HIGH,1,NX-1,1,NY,3,3,1,1000)
COVAL(BAFFLE1,W1,FIXVAL,0.0)
Baffle 2 at NZ=5
PATCH(BAFFLE2,HIGH,2,NX,1,NY,5,5,1,1000)
COVAL(BAFFLE2,W1,FIXVAL,0.0)
Resistance to flow exerted by tubes, throughout the shell.
PATCH(RESIST,PHASEM,1,NX,1,NY,1,NZ,1,1000)
COVAL(RESIST,U1,RESCO,0.0);COVAL(RESIST,V1,RESCO,0.0)
COVAL(RESIST,W1,0.5*RESCO,0.0)
GROUP 15. Termination of sweeps
LSWEEP=100
GROUP 16. Termination of iterations
LITER(P1)=100
GROUP 17. Under-relaxation devices
RELAX(U1,FALSDT,1.0);RELAX(V1,FALSDT,1.0)
RELAX(W1,FALSDT,1.0)
RELAX(1STH,FALSDT,100.0);RELAX(2NDH,FALSDT,100.0)
GROUP 19. Data communicated by satellite to GROUND
NAMSAT=MOSG
GROUP 20. Preliminary print-out
GROUP 21. Print-out of variables
Print-out of porosities is suppressed.
OUTPUT(EPOR,N,N,N,N,N,N);OUTPUT(NPOR,N,N,N,N,N,N)
OUTPUT(HPOR,N,N,N,N,N,N)
OUTPUT(1STH,Y,N,Y,Y,Y,Y);OUTPUT(2NDH,Y,N,Y,Y,Y,Y)
GROUP 22. Spot-value print-out
IXMON=6;IYMON=6;TSTSWP=5
GROUP 23. Field print-out and plot control
IPLTL=LSWEEP;IPROF=1;ORSIZ=0.4;XZPR=T;NPLT=1
PATCH(PASS1,PROFIL,1,1,2,2,1,NZ,1,1000)
PLOT(PASS1,1STH,T2IN,T1IN);PLOT(PASS1,2NDH,T2IN,T1IN)
PATCH(PASS2,PROFIL,2,2,2,2,1,NZ,1,1000)
PLOT(PASS2,1STH,T2IN,T1IN);PLOT(PASS2,2NDH,T2IN,T1IN)
PATCH(PASS3,PROFIL,3,3,2,2,1,NZ,1,1000)
PLOT(PASS3,1STH,T2IN,T1IN);PLOT(PASS3,2NDH,T2IN,T1IN)
PATCH(PASS4,PROFIL,4,4,2,2,1,NZ,1,1000)
PLOT(PASS4,1STH,T2IN,T1IN);PLOT(PASS4,2NDH,T2IN,T1IN)
tstswp=-1
dmpstk=t
DISTIL=T
EX(P1)=1.191E+02; EX(U1)=3.000E-01
EX(V1)=2.262E-02; EX(W1)=3.339E-01
EX(1STH)=4.835E-01; EX(2NDH)=4.681E-01
LIBREF=110
STOP