radiation transfer between solid and fluid zone
 

Dear all,

I'm modeling a radiation problem by using DO model. I have a fluid(air) zone in adjacent to a solid(silicon) zone. I select to couple two walls between them, and I also select "participate in radiation" for solid zone. (1) So how is the energy transferred between these two zones? (2) since i only want to model radiation, not the heat conduction, I choose the set the thermal conductivity of air to a very small number so as to only allow the radiation transfer. I also set a very small thermal conductivity of solid substrate so there're no heat transfer inside it. When I've done the simulation, I found in the contour results that the "incident radiation" uniformity is different from the "temperature". Do you have any idea how this happens?

Regards Thomas