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conjugate heat transfer in a rotary condition

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Old   June 13, 2013, 08:31
Default conjugate heat transfer in a rotary condition
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Alireza
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Dear all,

I intend to simulate the problem of the conjugate heat transfer in the rotary condition. I have a brick with heat source that is surrounded by air. both the fluid and solid (brick) are rotating with the same velocity. It is worth mentioning that to check the solution, the amount of the heat transfer in the wall and wall-shadow must be almost equal.

In my case, as long as the rotation speed is zero the results is ok. However, as i active the rotation, i can't converge the energy equation so that there is a considerable difference in the amount of heat transfer in the wall a in the wall-shadow.

in your view, is it better if i changer the solver namely CFX? or is there something wrong with my meshing? or anything else?

Thanks for your kind concern.

best,
Alireza
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Old   June 13, 2013, 09:33
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Karl Kargl
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Hi,

maybe you have a look inside the FLUENT User Guide. There it says:


"For solid zones, you only need to activate the Frame Motion option if you intend to include
the convective terms in the energy equation for the solid (Equation 5.11 in the
Theory Guide). Normally, this is not required if you want to do a conjugate heat transfer
problem where the solid and fluid zones are moving together."

So in your case (if the convective terms are neglible) you can set the solid zone to stationary because it is linked through the coupled walls with the rotating fluid zone.

There is also a presentation which you can find on the Ansys Customer portal, called "Conduction Heat Transfer - Modeling Heat Transfer Using FLUENT". There you can find some additional informations about the solver parameters if your solution is still diverging.

Best Regards,
Karl
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Old   June 17, 2013, 03:15
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Alireza
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Dear Karl,

Thanks for your reply, I really appreciate it.

In line with your comments, I disabled the solid motion and just linked it with the fluid wall in boundary conditions. In this way, the heat transfered to the wall shadowthrough solid wall is compatible with the energy source in the solid body. However, there is a problem since the amount of heat flux to solid wall is higher than that to wall shadow. (Is it necessary the amount of the heat transfer in the wall and wall-shadow to be almost equal?)

Unfortunately, I couldn't find the aforementioned presentation file. I would be highly appreciated if you could send it to me.

best wishes,
Alireza

Last edited by rasekh64; June 19, 2013 at 03:08.
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Old   June 18, 2013, 05:38
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Karl Kargl
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Hi,

normally this should be the same amount of heat on both sides. Only the sign differs. I have sent you the presentation.

Best Regards,
Karl
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Old   June 19, 2013, 03:11
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Alireza
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Hi,

I am sorry for bothering you. Could you please send me the presentation file to this my email "alireza.rasekh@gmail.com" because I couldn't find it here.

Best wishes,
Alireza
Quote:
Originally Posted by Karl View Post
Hi,

normally this should be the same amount of heat on both sides. Only the sign differs. I have sent you the presentation.

Best Regards,
Karl
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