Discussion Forum

Hello COMSOL experts,

I´m new to COMSOL and started my first heat transfer simulation. In version 5.2a I try to figure out whats the best method to simulate radiative heat transfer from one steel block to another.

Therefore I use the "Heat Transfer in Solids" physics to set up all the heat sources, diffuse surfaces etc. Now in the menu of the "Heat Transfer in Solids" node there is a check box called "Surface-to-Surface Radiation" which I want. But when I start the solver he stucks at "Assembling matrices" forever (which may be due to a nonlinear problem).

Then there is another physics called "Heat Transfer with Surface-to-Surface Radiation". The menu looks very much the same as in the "Heat Transfer in Solids" node.

Question 1: I´m wondering whats the difference between these two physics? And which one fits better for my heat radiation problem?

Question 2: It seems like the solver needs an eternity to solve my problem because of the checked Surface-to-Surface Radiation check box (because without I get a fast solution). Is there a way to simplify the problem so that it can be solved in an acceptable time?

Thanks alot for your answers!