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hi everyone

is comsol has a tool to integrate heat flux (W/m^2) over boundary and give the local distribution of the integrated power (W) at each point on that boundry?

thanks

5 Replies Last Post 01.04.2010, 14:53 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 30.03.2010, 15:04 GMT-4
Hi

Thra the "postprocessing - boundary integration" tab for a double integration, or edge integration (in 2D) for a simple integration.

Check the doc too, its worth it

Good luck
Ivar
Hi Thra the "postprocessing - boundary integration" tab for a double integration, or edge integration (in 2D) for a simple integration. Check the doc too, its worth it Good luck Ivar

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Posted: 1 decade ago 01.04.2010, 01:48 GMT-4
Thanks lvar

I already did but this give the total numerical value, is there any method to plot this integration at each point?

I do appreciate your help to me and others
Amir
Thanks lvar I already did but this give the total numerical value, is there any method to plot this integration at each point? I do appreciate your help to me and others Amir

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 01.04.2010, 02:42 GMT-4
Hi

Well then I beleive you must explain a little more as I do not understand you fully:

such as : are you in 2D or 3D, are you wanting to integrate over 1D of a 2D boundary or ?

Ivar
Hi Well then I beleive you must explain a little more as I do not understand you fully: such as : are you in 2D or 3D, are you wanting to integrate over 1D of a 2D boundary or ? Ivar

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Posted: 1 decade ago 01.04.2010, 12:18 GMT-4
Hi lvar

So let me explain my case. I have 3D model as follows:

10mmx10mm heat source under a copper spreader that 40mmx40mm (100% in contact). everything is isolated except the upper face of the spreader so all the heat supplied will be taken from the upper face OK. when I give power to the heating element the heat will spread out due to area expansion on the spreader surface. After I reach the required condition , I need to plot the heat flux (W/m^2) as a function of the position (x) on the spreader surface (upper face) this can be done, but instead of the heat flux I need to plot the power(W) as function of x so I need to integrate the heat flux and get the local distribution of the power at the upper face of the spreader. boundary integration gives me a numerical value but need to plot the power vs x.

I hope I explained in good way ( I am experimental person and I just start learn simulation)

Thanks
Hi lvar So let me explain my case. I have 3D model as follows: 10mmx10mm heat source under a copper spreader that 40mmx40mm (100% in contact). everything is isolated except the upper face of the spreader so all the heat supplied will be taken from the upper face OK. when I give power to the heating element the heat will spread out due to area expansion on the spreader surface. After I reach the required condition , I need to plot the heat flux (W/m^2) as a function of the position (x) on the spreader surface (upper face) this can be done, but instead of the heat flux I need to plot the power(W) as function of x so I need to integrate the heat flux and get the local distribution of the power at the upper face of the spreader. boundary integration gives me a numerical value but need to plot the power vs x. I hope I explained in good way ( I am experimental person and I just start learn simulation) Thanks

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 01.04.2010, 14:53 GMT-4
Hi

well I suspect its the Extrusion coupling variables you are looking for, but let us do a dimensional check first:

You solve to get the power density over the surface it's expressed in in [W/m^2] so if you want the total power you integrate this power density with a double "boundary integration" over dx*dy which gives you a total power in [W] (the 1/m^2 is multiplied by the two "m" units of dx and of dy).

But you say you want the power as a function of X, so what you really want is probably the integration only over "dy" and the linear power density is thus expressed in W/m along an edge, but it will be dependent on x, so if you integrate once more along dx along this edge you will end up with the same total power.

If this is the case, yes it's the extrusion integration coupling variable you should study, see "guide.pdf" p275 in the 3.5a doc

You will find examples in the application docs too

good luck
Ivar
Hi well I suspect its the Extrusion coupling variables you are looking for, but let us do a dimensional check first: You solve to get the power density over the surface it's expressed in in [W/m^2] so if you want the total power you integrate this power density with a double "boundary integration" over dx*dy which gives you a total power in [W] (the 1/m^2 is multiplied by the two "m" units of dx and of dy). But you say you want the power as a function of X, so what you really want is probably the integration only over "dy" and the linear power density is thus expressed in W/m along an edge, but it will be dependent on x, so if you integrate once more along dx along this edge you will end up with the same total power. If this is the case, yes it's the extrusion integration coupling variable you should study, see "guide.pdf" p275 in the 3.5a doc You will find examples in the application docs too good luck Ivar

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