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Old   May 14, 2011, 15:13
Default heat transfer conjugated CFD
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wild
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folks,

I have been suffering heat transfer conjugated CFD for rotating machinery for a while.

main problem is some cells tend to reach extreme temperature. I have switched off that temperature secondary order. And all of boundary conditions have been set up all right, for sure. Maximum skewness to mesh is 0.96.

I heard some others also had heat transfer conjugated convergence problem. Does it mean that FLUENT is not robust for this kind of problem?

Any ideas?

thanks.
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Old   May 16, 2011, 05:47
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jsm
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Hi

For volume mesh, the quality should be less than 0.9. Otherwise this will create convergence problems and high values at some points. Improve the mesh quality and then rerun the case.

with regards,
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Old   May 16, 2011, 15:58
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Quote:
Originally Posted by jsm View Post
Hi

For volume mesh, the quality should be less than 0.9. Otherwise this will create convergence problems and high values at some points. Improve the mesh quality and then rerun the case.

with regards,
Thanks for the reply, JSM.

I have tried to reduce highest skewness to about 0.91. I think it might be enough.

The thing is FLUENT looks converges solution a little bit, but very slowly. However, this is just for isotropic thermal conductivity properties. Once I switch thermal conductivities into cyl orthotropic ones, local temperature immediately goes up quickly and it has the trend to reach extreme temeprature very soon.

I heard from FLUENT engineers that solutions converges easily in case of istotropic materials, but might be hard for orthotropic ones.

Anyone else has any idea or suggestions?

thanks!
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