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## Geometry

Hello!!!!!!

I'm trying to do heat transfer + joule heating between two rectangles. But when I do the geometry I have two rectangles together (2 domains) 1 domain is the joule heating, and I have a problem here because I have automatically boundary conditions between the two domains as thermal isulation and electrical insulation, then the heat cannot flux to the other domain and I cannot remove this boundary. Could somebody help me?? how I have to draw the geometry or how can I manage the boundaries?

Thank you very much

Yolanda

1 Reply Last Post Dec 5, 2012, 2:42 PM EST
Posted: 5 years ago
Hi

that depends on how you set up your physics. If you choose "geometry union" mode, COMSOL assumes continuity for all internal boundaries between domains that are in the same "physics" and external boundaries at the limit of the physics.

Now if you have 2 domains (i.e. rectangles in 2D or blocks in 3D) and define two physics one for each then the common geometrical boundary is an external boundary for each of the two physics. So you need to define your continuty manually. On the other side both HT and JH solves for T so probably you get T and T2 and you need to couple these two.

There is a better way: use only one of the two physics for both domains, probably the Joule Heating, then you can define a new domain node under JH for sold HT only where you have no current, if this does not work, try to give it a very low conductivity i.e. 1 S/m that should also do. In this way you have only one dependent temperature value T and COMSOL looks after the continuity issues on common boudaries for you

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Good luck
Ivar

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