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Joule heating

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Hi i am using eletrothermal model (joule heating) - attached file. We are considering conduction heat transfer only. But we are having 2 problems:

  • when we run the stationary study, we get an error saying "Returned solution has not converged"

  • when we run the time dependent study, the solver works. The voltage distribution seems ok but the temperature distribution is too high (we were expecting max temp around 300K).

It is such a simple a model, we could not find the mistake. Any help is much appreciated.

Thank you



4 Replies Last Post 11.07.2023, 08:54 GMT-4
Robert Koslover Certified Consultant

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Posted: 1 year ago 08.07.2023, 18:23 GMT-4

I just took a quick look at your model. I may have missed something, but you appear to have specified all the external model boundaries as providing perfect thermal insulation. If you deposit heat continuously within a thermally-insulated object, its temperature will rise without bound.

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Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
I just took a quick look at your model. I may have missed something, but you appear to have specified all the external model boundaries as providing perfect thermal insulation. If you deposit heat continuously within a thermally-insulated object, its temperature will rise without bound.

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Posted: 1 year ago 09.07.2023, 02:05 GMT-4

Dear Robert ,

Thank you for the solution . Could you please let me know which boundry should be used for heat flux .

Dear Robert , Thank you for the solution . Could you please let me know which boundry should be used for heat flux .

Robert Koslover Certified Consultant

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Posted: 1 year ago 09.07.2023, 15:52 GMT-4

>

Thank you for the solution . Could you please let me know which boundry should be used for heat flux .

That's for you to decide, based on the environment of the object! Is it immersed in a gas, a fluid, a vacuum? Is it in contact with another solid? Even if isolated in vacuum, it can still radiate heat away if you define the appropriate boundary conditions. You might want to take a look at some of the example thermal models provided in the Comsol Application Library, since some of those may be directly relevant to your problem. There are many good ones, including variously conduction, convection, and radiation. There are also several tutorial thermal models, which generally provide more detailed guidance and explanations (see their pdf files) than the other examples.

-------------------
Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
> >Thank you for the solution . Could you please let me know which boundry should be used for heat flux . That's for you to decide, based on the environment of the object! Is it immersed in a gas, a fluid, a vacuum? Is it in contact with another solid? Even if isolated in vacuum, it can still radiate heat away if you define the appropriate boundary conditions. You might want to take a look at some of the example thermal models provided in the Comsol Application Library, since some of those may be directly relevant to your problem. There are many good ones, including variously conduction, convection, and radiation. There are also several *tutorial* thermal models, which generally provide more detailed guidance and explanations (see their pdf files) than the other examples.

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Posted: 1 year ago 11.07.2023, 08:54 GMT-4

Dear Robert ,

Thank you . I will go through the same.

Dear Robert , Thank you . I will go through the same.

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