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Heat source: Temperature profile instead of heat

Posted 22 mai 2013, 11:56 UTC−4 Heat Transfer & Phase Change Version 4.3a 7 Replies

Sandra
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Hi,

I want to use measured values to define a heat source in the "Conjugate Heat Transfer". I could already generate a 3D-function of these values which can be used as Q. But my problem is that the values are temperatures in Kelvin and not a heat in W/m^3.
So does somebody now how to use a temperature profile instead of the heat?

Thanks
Sandra
7 Replies Last Post 27 mai 2013, 09:31 UTC−4
Francesco Carelli
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Posted: 1 decade ago 24 mai 2013, 05:32 UTC−4
I am not sure it could work, it's just ani idea, since i used always temperature as output, not input, except in boundary conditons, but have you tried to set as initial conditions the temperature in your heat source setting a really high heat capacity in the heat source region?
For small transients could be a way for emulate a constant heat source.
I am not sure it could work, it's just ani idea, since i used always temperature as output, not input, except in boundary conditons, but have you tried to set as initial conditions the temperature in your heat source setting a really high heat capacity in the heat source region? For small transients could be a way for emulate a constant heat source.
Sandra
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Posted: 1 decade ago 27 mai 2013, 05:02 UTC−4
Hi,

thank you for your answer.
But I do not really understand what you mean. Maybe the idea is to choose a high heat capacity in order to get similar values of Q and T? I hoped for an easier way to just use the temperature. But I will think it over.

Sandra
Hi, thank you for your answer. But I do not really understand what you mean. Maybe the idea is to choose a high heat capacity in order to get similar values of Q and T? I hoped for an easier way to just use the temperature. But I will think it over. Sandra
Edgar J. Kaiser Certified Consultant
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Posted: 1 decade ago 27 mai 2013, 05:11 UTC−4

Sandra,

if I understand you correctly it is easy. Use a temperature boundary condition and assign your temperature function to it.

Cheers
Edgar

--
Edgar J. Kaiser
www.emphys.com
Sandra, if I understand you correctly it is easy. Use a temperature boundary condition and assign your temperature function to it. Cheers Edgar -- Edgar J. Kaiser http://www.emphys.com
Sandra
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Posted: 1 decade ago 27 mai 2013, 05:26 UTC−4
Hi Edgar,

at first I tried it with the temperature boundary condition like you suggested. But I have a 3 dimensional temperature distribution in an 3D-area and not only on a boundary. I do not only want to set a temperature distribution on the surface of e.g. an ellipsoid but there should also be a temperature value for every point inside of it.

Correct me if I'm wrong but I don't think that it is possible to use the temperature boundary condition for this purpose.

Sandra
Hi Edgar, at first I tried it with the temperature boundary condition like you suggested. But I have a 3 dimensional temperature distribution in an 3D-area and not only on a boundary. I do not only want to set a temperature distribution on the surface of e.g. an ellipsoid but there should also be a temperature value for every point inside of it. Correct me if I'm wrong but I don't think that it is possible to use the temperature boundary condition for this purpose. Sandra
Edgar J. Kaiser Certified Consultant
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Posted: 1 decade ago 27 mai 2013, 07:47 UTC−4

Sandra,

I would say that the inside of the domain doesn't contribute to the model if it just remains at a fixed temperature. Only the boundary interacts with the 'variable' part of the model.
But I may still not completely understand what you are after exactly.
--
Edgar J. Kaiser
www.emphys.com
Sandra, I would say that the inside of the domain doesn't contribute to the model if it just remains at a fixed temperature. Only the boundary interacts with the 'variable' part of the model. But I may still not completely understand what you are after exactly. -- Edgar J. Kaiser http://www.emphys.com
Sandra
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Posted: 1 decade ago 27 mai 2013, 09:06 UTC−4
Hi Edgar,

you're right, usually it would be like this. I forgot to mention that I want to have this temperature contribution in every point because I want a laminar flow to go through this area. So I don't want to define a solid with a temperature on its surface but an area with the same properties like the flowing fluid.

The reason for this is that later I want to simulate a plasma with a fluid flow. But as a first step and since I got the measured temperature profile of the plasma my idea was to just set up an area with this temperatures to find out how the heat would affect the fluid flow.

Sandra
Hi Edgar, you're right, usually it would be like this. I forgot to mention that I want to have this temperature contribution in every point because I want a laminar flow to go through this area. So I don't want to define a solid with a temperature on its surface but an area with the same properties like the flowing fluid. The reason for this is that later I want to simulate a plasma with a fluid flow. But as a first step and since I got the measured temperature profile of the plasma my idea was to just set up an area with this temperatures to find out how the heat would affect the fluid flow. Sandra
Edgar J. Kaiser Certified Consultant
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Posted: 1 decade ago 27 mai 2013, 09:31 UTC−4

Well, then you might try to do it Francesco's way. Your attempt is a bit 'unphysical' because T is the dependent variable.

Cheers
Edgar

--
Edgar J. Kaiser
www.emphys.com
Well, then you might try to do it Francesco's way. Your attempt is a bit 'unphysical' because T is the dependent variable. Cheers Edgar -- Edgar J. Kaiser http://www.emphys.com

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