Discussion Forum

Hello Everyone,

I need some help verifying what I did in COMSOL 4.4. I wanted to model how a transparent glass layer with an opaque polymer layer beneath it changes structurally and thermally to solar radiation. For that, I used the Thermal Stress physics that combines the heat transfer and structural mechanics modules in COMSOL 4.4.

I used the Surface to Surface Radiation module to enable the External Radiation source option. My assumption is that the glass is always transparent to all solar radiation wavelengths and the polymer is always opaque, so as to simplify the problem. Also, I used an External radiation source at infinity instead of the actual Solar Position Radiation source. I have one Surface to Surface Radiation node for the surface in between the glass and polymer and one for the bottom surface of the polymer. I have convective cooling for the top and bottom surfaces of the system.

My first question is, what does the transparent media refractive index option in the main Heat Transfer in Solids node mean? Is it the refractive index of the ambient air or is it the refractive index of the glass? I plugged in the value of glass and got some results and for the value of air, I got some different results.
My second question is, is what I am doing correct in terms of the physics involved?

Thanks,
Mahesh