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heat generation calculation

Posted Dec 18, 2012, 9:28 a.m. EST RF & Microwave Engineering, Heat Transfer & Phase Change Version 4.2 4 Replies

Sezin Tuta
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Hi,

I am modelling microwave heating by Comsol 4.2

I used heat source domain and electromagnetic power loss density as heat source

but I couldn't calculate heat generation terms (W/m^3)

When I use total heat source in volume average, it couldn't becalculated,

Can anyone help me about it?
4 Replies Last Post Dec 19, 2012, 8:27 a.m. EST
Sergei Yushanov Certified Consultant
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Posted: 1 decade ago Dec 18, 2012, 10:44 a.m. EST
In the Heat Transfer node, add Heat Source for domain.
In the Settings window for Heat Source 1, select domain where heat is generated. Then, in the Heat Source>General source section, select User defined and type in emw.Qrh. (Alternatively, select “Total power dissipation density (emw/wee1)” as General source for Q).



Good luck,
Sergei
In the Heat Transfer node, add Heat Source for domain. In the Settings window for Heat Source 1, select domain where heat is generated. Then, in the Heat Source>General source section, select User defined and type in emw.Qrh. (Alternatively, select “Total power dissipation density (emw/wee1)” as General source for Q). Good luck, Sergei
Sezin Tuta
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Posted: 1 decade ago Dec 19, 2012, 2:07 a.m. EST
Hİ,

Yes I am doing like this

but when I calculate total heat source value opened window writes

"evaluation of result expression failed"

I do calculate; results>derived values>volume average>total heat source

I can not understand what I must?

could you help me please?
Hİ, Yes I am doing like this but when I calculate total heat source value opened window writes "evaluation of result expression failed" I do calculate; results>derived values>volume average>total heat source I can not understand what I must? could you help me please?
Sergei Yushanov Certified Consultant
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Posted: 1 decade ago Dec 19, 2012, 7:17 a.m. EST
Sezin,

Under Global Definitions>Parameters, define variable “freq” and assign actual numerical value of the frequency you are using to this variable. Update the model and I suspect that error message “evaluation of result expression failed” will disappear.

Good luck,
Sergei
Sezin, Under Global Definitions>Parameters, define variable “freq” and assign actual numerical value of the frequency you are using to this variable. Update the model and I suspect that error message “evaluation of result expression failed” will disappear. Good luck, Sergei
Sezin Tuta
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Posted: 1 decade ago Dec 19, 2012, 8:27 a.m. EST
Hi,

it is ok now

thanks a lot...
Hi, it is ok now thanks a lot...

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