Hi,
I'm simulating Heat transfer via Cavity radiation, but the results differ a lot from the analytical values. Also variations of the emissivity value doesn't change the results in the expected magnitude.

Is there any command I'm missing or used wrong?
It's just two Surfaces (Fire and Steel) facing each other and the radiation is defined as follows:

*Surface Property, name=Feuer
*Emissivity
1.
*Film Property, name=Film
0.025
*Surface Property, name=Träger
*Emissivity
0.7
** 
** PHYSICAL CONSTANTS
** 
*Physical Constants, absolute zero=-273.15, stefan boltzmann=5.67e-08
** 
** PREDEFINED FIELDS
** 
** Name: Predefined Field-1 Type: Temperature
*Initial Conditions, type=TEMPERATURE
"alles für grundtemperatur", 20.
** 
** INTERACTIONS
** 
** Interaction: Cavity radiation_emissivität
*Cavity Definition, name="Cavity radiation_emissivität", Set property, ambient temp=20.
Feuer, Feuer
"Träger unten", Träger
** ----------------------------------------------------------------
** 
** STEP: Step-1
** 
*Step, name=Step-1, nlgeom=NO, inc=10000
*Heat Transfer, end=PERIOD, deltmx=2000., mxdem=1.
0.01, 3730., 0.0001, 50., 
** 
** BOUNDARY CONDITIONS
** 
** Name: BC-3 Type: Temperature
*Boundary
Feuer, 11, 11, 2000.
** 
** INTERACTIONS
** 
** Interaction: Cavity radiation_emissivität
*Radiation Viewfactor, cavity="Cavity radiation_emissivität"
** 

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