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-   -   Heat flux and wall temperature divergence (http://www.cfd-online.com/Forums/fluent/114060-heat-flux-wall-temperature-divergence.html)

Mat_fr March 4, 2013 13:04

Heat flux and wall temperature divergence
 
Dear all,

I would like to simulate just a simple heat transfer from a wall to the fluid.
When I impose the wall temperature in the thermal BC, everything is going fine.
However, when I impose a surface heat flux (W/mē), the wall temperature is diverging, or is converging towards a very high T (non-physical) when I'm using limiters.
I suppose this is due to the fact that my fluid is stagnant. And numerically, the soft has trouble to handle it.

I already refined my mesh. It's better, but I still have non-physical wall temperature.

Does anybody has a solution or a suggestion ?

Thanks in advance !

Remark : I have a cooling wall in the domain with the opposite heat flux, in order to be at equilibrium.

Ardali March 4, 2013 13:17

That's free convection?

Mat_fr March 6, 2013 09:58

Dear Ardali,

Thanks for your answer, which maked me verify something !

As the fluid is stagnant, it is free convection, indeed. That is why, I enabled the boussinesq approximation.
However, I didn't capture any convection, and as I said, the temperature was diverging.
In fact, I realized that the thermal expansion coefficient was set to 0... I suppose this the cause of the error.
I believed naivly that the Fluent Database would provide me some meaningfull value.

Sorry for this simple problem.

Best,

Mat


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