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Is there a way to do a temperature dependent heat source in Conjugated Heat Transfer?
Posted Apr 10, 2013, 6:42 a.m. EDT Fluid & Heat, Heat Transfer & Phase Change, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.3 6 Replies
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I'm working in the conjugated heat transfer physics and I'm hoping/wondering if there is a way to make the heat source temperature dependent.
I have a cable that is covered with different materials at different areas so the temperature in the copper wire fluctuates. Since the heat source is copper where the resistivity changes with the temperature and thus gives an uneven load across the length of the cable. I'm thinking that the option "general source" doesn't account for thìs?
I might be working in the wrong physics, but the thing is, I'm interested in is to improve the cooling of the cable. So I thought this would be the correct physics.
Any help would be much appreciated..
And by the way thanks for a brilliant forum.
Rógvi Østerø
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probably not fully, as with Joule heating you might get runaways, that I would not expect are so simple to get correct with only a heat source dependending on T.
On the other side, when you set a fixed T to a boundary, COMSOL is in fact calulating a fictuous heat source field (=depending on (x,y,z,t)) such that the boundary temperature fits your desired value. The results are a heat flux field exiting/entering the boundary (wich is mostly quite different from a scalar average value)
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Good luck
Ivar
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and thank your very much for your swift responses and I apologize for my slow respons.
I have looked at the Joule heating, but the thing is, that I'm interested in the air flow. And there is no option to add a volume force in Joule heating. The interest in air flow is due to the intent to apply the best cooling of the cable.
Should I combine the two physics or is there another "easier" way to simulate the change in resistivity?
With the heat source dependent on T, how would one go about doing this and could it be done in Conjugated heat transfer?
Your help is much appreciated.
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I would say use NITF and add simple joule heating by equations (because if you Add NITF and JH you end up with 2*T and you need to knit them together).
Another way is that you have the joule heating and the NITF on different domains, then by calling T=T for both physics or simply putting identity for T flux over the common boundary you should be able to use both physics without wrong couplings
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Good luck
Ivar
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Thank you very much for swift respons, I will give your suggestion a try and let you know how it goes.
And once again thank you very much for your help.