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TALK=F;RUN( 1, 1);VDU=VGAMOUSE
TEXT( Library case Y618: Global and self-steering underrelaxation
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PLANT information :
* Data input groups used: 17, 19
* Ground groups planted : 13, 19-2, 19-3
* Headings used : SC02??, SC03??, SORC??
* Functions used : None
* Commands used : IF, REGION
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** FLO1 = mass-flow rate of shell fluid
REAL(FLO1);FLO1=0.1
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.
Only one half of the exchanger is included in the
calculation domain, because of the symmetry of the
geometry.
GRDPWR(X,5,1.0,1.0)
GROUP 4. Y-direction grid specification
NY=3
GRDPWR(Y,NY,0.5,1.0)
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
five variables must be solved; only the enthalpy needs
be computed for the tube-side fluid.
SOLVE(P1,U1,V1,W1)
STORE(EPOR,NPOR,HPOR)
GROUP 8. Terms (in differential equations) & devices
TERMS(U1,Y,Y,Y,Y,Y,Y);TERMS(V1,Y,Y,Y,Y,Y,Y)
TERMS(W1,Y,Y,Y,Y,Y,Y)
GROUP 9. Properties of the medium (or media)
ENUL=10.
GROUP 11. Initialization of variable or porosity fields
FIINIT(W1)=FLO1;FIINIT(U1)=0.0;FIINIT(V1)=0.0
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(INLET1,CELL,1,1,2,3,2,2,1,1000)
COVAL(INLET1,P1,FIXFLU,FLO1/2.0)
** East boundary; shell fluid outlet; 2 cells in east wall
PATCH(OUTLET1,EAST,NX,NX,2,3,NZ-1,NZ-1,1,1000)
COVAL(OUTLET1,P1,FIXP,0.0)
** 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)
GROUP 15. Termination of sweeps
LSWEEP=400
GROUP 16. Termination of iterations
LITER(P1)=100
GROUP 17. Under-relaxation devices
NAMSAT=MOSG
RG(1)=ENUL
** Global under-relaxation
RG(2)=AMIN1(XULAST/FLOAT(NX),YVLAST/FLOAT(NY),$
ZWLAST/FLOAT(NZ))/$
AMAX1(U1,:FLO1:/2.)
REGION(1,1,2,3,2,2)
IF(ISWEEP.GT.100.AND.ISWEEP.LE.200)
DTFALS(U1)=RG(2)
REGION(1,1,1,1,1,1)
IF(ISWEEP.GT.100.AND.ISWEEP.LE.200)
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Global under-relaxation is introduced by PLANTed codings for
DTFALS(U1) at the start of each sweep. It is assumed to be equal to
the smallest of the cell sizes divided by the largest of inlet mass
flux velocity and local velocity magnitude normal to the inlet
plane. It is applied over the whole domain for the velocity in
question IF isweep is greater than 100 but less or equal than 200.
Here and for next two statemnts, command REGION with unity arguments
is used to economize the operations needed for equivalences.
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DTFALS(V1)=RG(2)
REGION(1,1,1,1,1,1)
IF(ISWEEP.GT.100.AND.ISWEEP.LE.200)
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The above settings do for DTFALS(V1) what has been done for
DTFALS(U1) above.
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DTFALS(W1)=RG(2)
REGION(1,1,1,1,1,1)
IF(ISWEEP.GT.100.AND.ISWEEP.LE.200)
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The above settings do for DTFALS(W1) what has been done for
DTFALS(U1).
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** Local self-steering under-relaxation
PATCH(RELAX,PHASEM,1,NX,1,NY,1,NZ,1,1)
CO=1./TFAL
COVAL(RELAX,U1,GRND,SAME)
IF(ISWEEP.GT.200)
CO=1./TFAL
COVAL(RELAX,V1,GRND,SAME)
IF(ISWEEP.GT.200)
CO=1./TFAL
COVAL(RELAX,W1,GRND,SAME)
IF(ISWEEP.GT.200)
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Local self-steering under-relaxation is introduced through the
sources of momentum for the whole domain defined by PATCH named
RELAX, which TYPE is PHASEM, VALue is SAME, COefficient, which is
set to reciprocal of false-time step. It is applied for each sweep
greater than 200.
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** Local fals-time step
STORE(TFAL);OUTPUT(TFAL,Y,Y,Y,Y,Y,Y)
TFAL=1/(SQRT(U1**2+W1**2+V1**2)/$
AMIN1(DXU2D*1,AMIN1(DYV2D*1,DZ*1))+$
RG(1)/AMIN1(DXU2D*1,AMIN1(DYV2D*1,DZ*1))**2)
IF(ISWEEP.GT.200)
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The reciprocal of local self-steering false-time step is set to the
local velocity vector magnitude divided by smallest distance
between walls of continuity cell in question plus local
diffusivities, i.e. kinematic viscosities, divided by the smallest
distance squarred.
The variable TFAL, false-time, is provided to assist the
computations. It is calculated right at the start of each IZ-slab
for all sweeps greter than 200 and can be used to monitor the
variation of local magnitudes of false-time steps.
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GROUP 19. Data communicated by satellite to GROUND
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)
GROUP 22. Spot-value print-out
IXMON=NX-2;IYMON=2;IZMON=4
GROUP 23. Field print-out and plot control
IPLTL=LSWEEP;IPROF=1;ORSIZ=0.4;XZPR=T;NPLT=1
TSTSWP=-1
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
STOP