Problem in convection Boundary condition
 

Hi everybody,

I am modeling a window-blind system in a building in both 2D and 3D modeling.
When I use convection B.C for window surface to apply the heat generation rate, there is a problem. The heat generation rate dose not effect on my results and there is no heat transfer on outer surface of the window !!!!:confused::confused::confused:

I am using single fluid phase.

heat generation rate unit : W/m3. That is, problem you are going to solve must be out of question 3d

Thanks for your reply Oozcan,

I have the same problem for my 3D model as well. I was wondering if I need to define thickness for the boundary with convection assumption or it works for a window without thickness?

thickness is useless for convection.But if you wonder what happen in conduction, you need to activate and specify it.

I thought maybe because it is the volumetric heat generation and my boundary is face so it dose not work. However so far I tried with and without thickness but there is no difference. I am confused. it seems a easy model but there is a problem that I ca not find it yet.

I have told you volumetric heat generation unit:w/m3, that is valid for a volumetric geometry, like cylinder,. Boundary condition you have given is a face. Either heat flux or temperature should be specified.

Thanks for your reply, there is still question
 

Yes I got it. But there some thing that is confusing. In my new case for 2D and 3D model I can see changes in the results when I am changing the heat generation rate but the results fir 2D and 3D model are different for a particular model. According your answer it was :rolleyes:that the results for 3D model is accurate. But for even 2D or 3D model when the boundary with "heat generation rate" condition dose not have thickness the heat generation rate doesn't work and I don't know why? it is convection not conduction