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 vec cl;red con TFAL y 2 fil;.001 msg False-time under-relaxation distribution msg Press e to END ENDUSE GROUP 1. Run title TEXT( SELF-STEERING UNDER-RELAXATION DISPLAY The 3D flow in a shell om imaginery heat exchanger is simulated. The heat exchanger considered has two baffles within the shell. The self-steering local false-time under-relaxation for the velocities is introduced by PLANTed codings for sources as follows: TYPE is PHASEM, VALue is SAME, CO, which is reciprocal of DTFALS, 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. Interesting variants include comparison of the rate of convergence for conventional once-for-all under-ralaxations and PLANTed ones for enul=0.0 and enul=1000 as for NX*NY*NZ=5*3*8, and for NY=3 and NY=10 as for enul=0.0. FLO1 = mass-flow rate of shell fluid ENDDIS enul=100.;rg(1)=enul ny=3 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 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 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=100 GROUP 16. Termination of iterations LITER(P1)=100 GROUP 17. Under-relaxation devices NAMSAT=MOSG PLANTBEGIN PATCH(RELAX,PHASEM,1,NX,1,NY,1,NZ,1,1)CO=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 COVAL(RELAX,U1,GRND,SAME) CO=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 COVAL(RELAX,V1,GRND,SAME) CO=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 COVAL(RELAX,W1,GRND,SAME) 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) PLANTEND 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 dmpstk=t DISTIL=T EX(P1)=3.704E+03; EX(U1)=3.000E-01; EX(V1)=2.755E-02 EX(W1)=3.252E-01; EX(TFAL)=2.776E-04 LIBREF=115 STOP