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dp June 2, 2006 08:40

Convergence in a conjugate heat transfer problem
 
Hello guys,

I am solving a conjugate heat transfer flow problem with heat generation. I am getting good convergence of Fluid parameters WITH little tunig of underrelaxation parameters.But for solid MATERIAL enthalpy residuals are not converging. HOW TO GO FOR IT.also how to set convergence criteria for solid seperately. Thanks in advance.


DenizeN June 5, 2006 03:53

Re: Convergence in a conjugate heat transfer probl
 
Try duble precision.

katghir June 5, 2006 10:08

Re: Convergence in a conjugate heat transfer probl
 
use PISO algorithm. using steady state sol not converged means try to use transient (Pseudo transient).


dp June 6, 2006 00:11

Re: Convergence in a conjugate heat transfer probl
 
Thanks a lot. let me try.

Stephen June 6, 2006 06:40

Re: Convergence in a conjugate heat transfer probl
 
The problem is that the thermal response times of your solid and fluid are probably very different.

If your problem is not bouyancy dependedent, you could try switching of the enthalpy solver and solving just the flow field - once this has converged, do the opposite, switch off solution of everything apart from enthalpy and continue the calculation.


moritz June 8, 2006 10:31

Re: Convergence in a conjugate heat transfer probl
 
I had the same problem, and I get the best convergence with a "solid cell temperature under-relaxation factor" of 0.999 ("thermal options" panel or conj,on,0.999), with 1 it doesn't converge and with 0.9 very slowly. Please let me know if this helps. In the StarCD user guide it is recommended to leave just one under-relaxation factor below 1. So try to set the fluid under-relaxation factor to 1.

dp June 9, 2006 00:53

Re: Convergence in a conjugate heat transfer probl
 
Thanks for the suggestions.Let me try and see. I will let u know whether it works.


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