Here are the assumptions of radiation for thermal analysis in SOLIDWORKS Simulation, I have bolded the relevant bits.
Emissivity is the only quantity that can be input into the program. Transmissivity of materials cannot be taken into account for thermal analysis in Simulation. Therefore, absorption+reflectivity =1. When the user inputs emissivity, the program calculates the absorption.
You have to select all the faces that participate in the heat exchange by radiation, meaning faces that will receive and emit radiation. Any surface you define radiation on will be able to absorb radiation. You can choose all faces which have the same emissivity factor at one step. Emissivity and absorption are handled equally, that means you can choose the inner side of the heated plate as well as the opposite face of the other plate at one step.
When you define radiation and there are other surfaces in the area that will be affected you will need to select the surface to surface radiation. This is where the view factor comes in. The view factor is a value that adjusts for how the radiation is transferred from surface to surface.
When you select surface to ambient, radiation effects for that surface will not affect any other surface. However, it will feel the effects of other radiating surfaces that are set to surface to surface.
Hope this helps
thank you for the answer.
from your answer, I did not understand how Solidworks Simulation calculates the absorption, could you please clarify this question?
For example, I have a solar panel, which has emissivity coefficient of 0.825, and absorptivity coefficient = 0.805. If I input emissivity as 0.825, which value for absorptivity in this case? The same as emissivity? or 0.175?
relatively to the "open" and "close" systems as well as selection of surfaces - thank you, it is pretty clear