definition difficulty-->DO radiation model

Harry Qiu

Dear Mr. or Mrs.:

How are you.

I'm modeling laminar premixed gasous combustion.

There are two zones in my geometry model, solid and fluid. The fluid zone is surrouded by the solid zone. the fluid is flue gas, and solid is ceramic(a type of non-penetratable material).

I want to model the radiatin of both ceramic wall and flame(flue gas).

After I define DO(discrete ordinat) model, I meet two difficulties :

(1)I don't know how to define absorption coefficient for solid(ceramic) in "Material Panel". As we all know, FLUENT set solid absorption coefficient as zero by default. Can I keep this default value "zero" as non-penetratable solid absortion coefficient?

(2)When I define Boundary condition, I have to set solid zone "Participate in radiation", otherwise wall radiation will not be calculated when iteration is started. Will radiation in the interior of the solid zone be computed as in the flue gas since I set solid absorption coefficient as zero and specify solid zone "Participate in radiation"?

One more question3)Can I calculate wall radiation(no fluid radiation) without define any radiation model?

looking forward to your answer!

Tank you for your help.

Sincerely yours, Harry Qiu.