GROUP 1. Run title and other preliminaries TEXT(1D Radiant Heat Transfre In A Box TITLE DISPLAY Radiative heat transfer takes place between parallel flat wide surfaces. The medium between them is at rest, and can absorb, emit and scatter radiation, as well as conducting heat. Wall temperatures and emissivities are prescribed. The RADIAT command is used to activate the radiation model of subroutine GXRADI. The solved-for variables are enthalpy, H1, and the composite radiation flux, RADX, defined as the arithmetic mean of the radiation fluxes in the +X and -X directions. RADX has a diffusivity which depends on the scattering and absorption coefficients. Press RETURN to continue readvdu(nphi,int,nphi) The wall boundary condition for RADX has a Value equal to the gross radiation flux emitted by the wall; thus the net flux is proportional to: sigma*Tw**4 - RADX The COefficient for RADX is a function of emissivity. The locally-defined parameters are as follows: GSIGMA Stefan-Boltzmann constant SCAT Scattering coefficient ABSORB Absorption coefficient EMIH emissivity of the hot wall EMIC emissivity of the cold wall THOT hot wall temperature TCOLD cold wall temperature REAL(GSIGMA,SCAT,ABSORB,EMIH,EMIC,THOT,TCOLD) GSIGMA=5.6697E-8;SCAT=0.05;ABSORB=0.2;EMIH=0.5;EMIC=0.2 THOT=600.0;TCOLD=300.0 ENDDIS mesg(Hot and cold temperatures are :THOT: and :TCOLD: mesg(Scattering and absorption coeffs. are :SCAT: and :ABSORB: GROUP 3. X-direction grid specification ** Symmetrical power-law grid set by using negative number of intervals GRDPWR(X,-20,1.0,1.5) GROUP 7. Variables stored, solved & named RADIAT(FLUX,ABSORB,SCAT,H1) GROUP 9. TERMS(h1,n,n,p,p,p,p) GROUP 9. Properties of the medium (or media) CP1=1.0;TMP1=LINH;TMP1B=1.0/CP1;ENUL=1.0E-3 ** Prandtl number of medium PRNDTL(H1)=0.7 GROUP 11. Initialization of variable or porosity fields FIINIT(RADX)=GSIGMA*((THOT+TCOLD)*0.5)**4 FIINIT(H1)=(THOT+TCOLD)*0.5 GROUP 13. Boundary conditions and special sources ** Net radiation flux from wall PATCH(WESTR,WEST,1,1,1,NY,1,1,1,1) COVAL(WESTR,RADX,EMIH/(2.0-EMIH),GSIGMA*THOT**4) PATCH(EASTR,EAST,NX,NX,1,NY,1,1,1,1) COVAL(EASTR,RADX,EMIC/(2.0-EMIC),GSIGMA*TCOLD**4) ** Heat conduction at wall WALL(WESTH,WEST,1,1,1,NY,1,1,1,1);COVAL(WESTH,H1,1.0,THOT) WALL(EASTH,EAST,NX,NX,1,NY,1,1,1,1);COVAL(EASTH,H1,1.0,TCOLD) GROUP 15. Termination of sweeps LSWEEP=25 GROUP 17. Under-relaxation devices RELAX(H1,FALSDT,.04) GROUP 22. Spot-value print-out IXMON=NX/2;NPLT=2 GROUP 23. Field print-out and plot control PATCH(XWISE,PROFIL,1,NX,1,1,1,1,1,1) PLOT(XWISE,H1,0.0,0.0);PLOT(XWISE,RADX,0.0,0.0) OUTPUT(H1,Y,Y,Y,Y,Y,Y) ITABL=1;TSTSWP=-1