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how to define Heat source?
Posted 2013/03/18 7:36 GMT-4 MEMS & Nanotechnology, Heat Transfer & Phase Change, MEMS & Piezoelectric Devices, Modeling Tools & Definitions, Parameters, Variables, & Functions, Studies & Solvers Version 4.2, Version 4.2a, Version 4.3, Version 4.3a 5 Replies
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I use COMSOL to simulate a microheater to heat the polymer waveguide on Silicon substrate.
The model is 2D. Silicon substrate serve as the heat sink at 25 degrees. When I set the microheater to 300 degrees, I can get a right a temperature distribution.
But now I want to set the microheater as the Heat source,and use the general source as 1000 W/m3. I set Bottom boundary at 25 degrees, and other boundaries as the Thermal Insulation. I can't get a right temperature distribution.
Can any experts on COMSOL tell me the reasons? Very urgent! Than you!
The version is Comsol 4.2.
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I believe its still to vague, and there an be too many reasons that we cannot give you any good hints, adding the model, cleaned for the solution and mesh could help us ;)
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Good luck
Ivar
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I also meet the similar problem.
I am confused on the Heat source.
In a 2D model, the bottom is heat sink at 20 degrees. The other 3 boundaries is themal insulation. Then a heater is at the center. I can't get the right result. The temperature is uniformly 20 degrees within the boundaries, not a right temperture distribution.
I don't know why.
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is this what you try to do ? its 4.3a
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Good luck
Ivar
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Thank you for your help.
Yes, If the heat source is set to Total power, I can get the result iin your attached figure.
But if the heat source is set to General source or Linear source, I can't get the right result.
See the attached, with "General source" setting.
I still do not know why?
PS: I am with 4.2 version.
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if its a general source you have other units, have you checked the energy flow, you see the gradients there in your image, it's "just" that your energ/powery in versus energy out ratio is not enough to give a huge temperature difference in steady state
That is my explanation at least, might be other things too
In anycase have you checked the simple analytical formulas, or looked at the total energy/poewer in versus out = energy balance of your steady state model there ?
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Good luck
Ivar