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Problem in convection Boundary condition

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Old   November 27, 2016, 23:46
Angry Problem in convection Boundary condition
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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 !!!!

I am using single fluid phase.
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Old   November 28, 2016, 04:43
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Quote:
Originally Posted by neda.m.b View Post
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 !!!!

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
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Old   November 28, 2016, 09:11
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Originally Posted by oozcan View Post
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?
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Old   November 28, 2016, 09:13
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Originally Posted by neda.m.b View Post
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.
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Old   November 28, 2016, 11:55
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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.
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Old   November 28, 2016, 12:51
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Originally Posted by neda.m.b View Post
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.
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Old   December 4, 2016, 10:23
Default Thanks for your reply, there is still question
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Originally Posted by oozcan View Post
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.
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 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
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