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divergence in termperature when thermal conductivity is zero

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Old   September 23, 2014, 04:01
Default divergence in termperature when thermal conductivity is zero
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Jacky
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Hi all,

I tried to remove thermal diffusion term by giving zero value for thermal conducitivity for the working fluid but fluent returned divergence in n temperature.... Can some one suggest how to do this.

Thanks & Regards,

Bharat
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Old   September 23, 2014, 04:12
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I suggest to set a value "very small"; the effect should be the same. Zero values in fluent are not good as there can be some division by zero..
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Old   September 23, 2014, 05:35
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Quote:
Originally Posted by ghost82 View Post
I suggest to set a value "very small"; the effect should be the same. Zero values in fluent are not good as there can be some division by zero..
Hi ,

Thanks for your reply. I also figured same thing. Can you answer me one more thing ?
I am presently modeling an enthalpy equation for mixture model for modeling boiling in porous media. In this eqn the convective flux is different from the one used by de3fault. SO I wrote a define-uds-flux macro for returning the desired value to the solver. Now when I give very small value to its diffusion coefficient, aftyer some iterations the solver gives divergence error.
However this was not so in the case of energy equation.....

Anmy feedback or sugggestion would be highly appreciated.

Thanks & Regards,

Bharat

PS: I have followed fluent's udf manual for writing define-uds-flux macro.
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