Radiation between surfaces that don't see each other

[pilafa]

Hi,

I have the set-up shown in the picture:

-----------------------------------
- A lamp

- A first semi-transparent body

- A second body
-------------------------------------

I define radiation boundary conditions on surfaces S1, S2 and S3:

Code: Select all

Boundary Condition ...
   Target Boundaries = ....
   Radiation Boundary Open = Logical True
   Radiation External Temperature = 298
   Heat Flux BC = True
   Radiation = Diffuse Gray
   Emissivity=0.9   
End

Surface S1 of the lamp heats up S2, but it wont heat S3. I think it's normal since S1 and S3 don't "see" each other.
Nevertheless, since Body 1 is semi-transparent, some radiation of the lamp will reach S3 (the portion not absorbed by Body 1). I would used an apparent fake emissivity for S3 to represent that.

So, I would like a work around to define radiation between S1 and S3. Any idea?

Thanks,
PL