```
#immersol)
#declare
TEXT(IMMERSOL- 1D fixed flux through domain :208
#cls
TITLE
DISPLAY

Radiative transfer occurs through a wide slab-shaped medium,
through one boundary of which radiant heat enters. The other
boundary is held at a fixed temperature.

The heat input to the wall is transferred to the first wall by
radiation and conduction across the space between them.

This space contains a gas of finite absorptivity.

The question to be answered is: what will be the temperature of
the first boundary, if the conductivity is set to zero?

ENDDIS
**************************************************************
PHOTON USE
AUTOPLOT
FILE
PHI 5

CL;DA 1 TEM1;DA 1 T3;COL3 1;BLB4 2;REDR
MSG    Temperature and T3 profiles.
ENDUSE
**************************************************************
#direct
MESG(  ENTER optical thickness Kr*Wg (default 1.):
WGAP = 1.0;  KGAS= 0.0258
KROSS= OPTHI/WGAP;  SCATT= 0.0;  EMISS= KROSS-SCATT
FIINIT(EMIS)=EMISS; FIINIT(SCAT)=SCATT
SOLVE(TEM1)
#geom2
TERMS(TEM1,N,N,Y,N,Y,N)
*** Set diffusivities for TEM1 and T3 (i.e. PRNDTL() must be
set to -Value). NOTE! value of diffusivity for T3 in a gas
is not important (correct value is calculated by EARTH);
PRNDTL(TEM1)= 1.e10
*** Set radiative heat flux through the domain:
COVAL(IMSWL1,T3,FIXFLU,1000.); COVAL(IMSWL2,T3,FIXVAL,500.)
LSWEEP= 50; SELREF=F; RESREF(T3)= 1.E-3
IXMON=NX/2+1;IYMON=NY/2+1;IZMON=NZ/2+1;
NXPRIN=1; NYPRIN=1; NZPRIN=1
OUTPUT(LTLS,N,N,N,N,N,N); OUTPUT(WDIS,N,N,N,N,N,N)

VARMIN(T3)=FIINIT(T3)*0.33;  VARMAX(T3)=FIINIT(T3)*3.0
VARMIN(TEM1)=FIINIT(TEM1)*0.33;  VARMAX(TEM1)=FIINIT(TEM1)*3.0

```