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Time Dependent Study for Electromagnetic Heating

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Hello, I'm working on an electrothermal model using the Electric currents(ec) and Heat Transfer in Solids(ht) Physics interfaces and the Electromagnetic Heating Multiphysics coupling(the default multiphysics coupling available for the two selected Physics interfaces). However, in the equation under the 'settings' of the Electromagnetic heating node, there is no definition of the term 'Qe' which is added to the multiphysics equation (as in the attached screenshot). I have a doubt as to how this term is being defined in the time dependent study. Is it defined as Qe=J*E ?? Thanking you in advance for any help.



3 Replies Last Post Sep 13, 2020, 3:57 p.m. EDT
Robert Koslover Certified Consultant

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Posted: 4 years ago Sep 12, 2020, 12:47 p.m. EDT
Updated: 4 years ago Sep 12, 2020, 12:52 p.m. EDT

Probably. The definition that you gave is listed explicitly for the stationary case. And, since you are using the ec module, you probably aren't interested in modeling other possible thermal losses that could arise due to high-frequency effects (like bulk dielectric microwave heating), right?

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Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
*Probably*. The definition that you gave is listed explicitly for the *stationary* case. And, since you are using the ec module, you probably aren't interested in modeling other possible thermal losses that could arise due to high-frequency effects (like bulk dielectric microwave heating), right?


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Posted: 4 years ago Sep 13, 2020, 1:00 p.m. EDT

Dear Robert sir, Thanks for your reply. Yes, my application involves operation only at the power frequency(50Hz). My main concern is that, since the defintion of Qe is not explicitly defined under the Electromagnetic heating multiphysics node for the time dependent study, how to be sure whether the dielectric loss has been included in the heat transfer equation ? or do I have to separately add a heat source node to the heat transfer(ht) physics interface defining it as the product (ec.normJ*ec.normE) to implement dielectric heating to my model ?

Dear Robert sir, Thanks for your reply. Yes, my application involves operation only at the power frequency(50Hz). My main concern is that, since the defintion of Qe is not explicitly defined under the Electromagnetic heating multiphysics node for the time dependent study, how to be sure whether the dielectric loss has been included in the heat transfer equation ? or do I have to separately add a heat source node to the heat transfer(ht) physics interface defining it as the product (ec.normJ*ec.normE) to implement dielectric heating to my model ?

Robert Koslover Certified Consultant

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Posted: 4 years ago Sep 13, 2020, 3:57 p.m. EDT
Updated: 4 years ago Sep 13, 2020, 4:00 p.m. EDT

I don't know. But you could always compare a frequency-domain solution to a time-domain one, where the latter is modeled with an equivalent (sinusoidal) function of time. The same physics should give the same answers, and that should settle the matter. Also, I wouldn't expect a lot of dielectric heating at 50 Hz. But then, I really don't know what you are modeling. I suggest you post your model to the forum so that the Comsol community can offer more specific advice & suggestions.

-------------------
Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
I don't know. But you could always compare a frequency-domain solution to a time-domain one, where the latter is modeled with an equivalent (sinusoidal) function of time. The same physics should give the same answers, and that should settle the matter. Also, I wouldn't expect a lot of dielectric heating at 50 Hz. But then, I really don't know what you are modeling. I suggest you post your model to the forum so that the Comsol community can offer more specific advice & suggestions.

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