radiation modeling in porous media
 

Hi everyone
Currently I am conducting a numerical study coupling solar radiation transfer and heat transfer using P1 approximation and LTNE model.
1) The issue is that I can't seem to write a UDF to simulate the radiation.
2) I assume that fluid properties are variable. But in the UDF of the heat transfer coefficient i should set the fluid properties as variable or constant ?
Can anyone provide the help for me ?
i will be grateful if anyone work on porous media solar receiver contact me or reply to my question

I'm confused :confused::confused::confused::confused:
Best regards