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Old   February 24, 2003, 03:25
Default Fluent and turbulent combustion
  #1
Daniel
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Hello,

Can anyone please tell me about the capabilities of Fluent in modeling non-premixed turbulent combustion problems without writing special subroutines, when compared to other CFD packages?

Thanks.
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Old   February 24, 2003, 05:44
Default Re: Fluent and turbulent combustion
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Jin-Wook LEE
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Fluent of course has traditional 'Arrhenius type finite rate chemistry' and 'eddy dissipation' based model. Other CFD packages also have them.

I think that Fluent's prePDF capability is fairly different model compared to the other codes. This model is based on

- Mixture Fraction

- PDF(Probability Density Function)

- Fast Chemistry with prescribed chemistry, e.g., Gibbs Free Energy Minimization.

The above model is fairly good, I think, for the treatment of the problem in which many species should be included.

Please remember that this model is suitable for the problem of 'turbulent mixing controlled combustion', not good for the problem of 'chemical kinetics controlled combustion'. ANd this model is not applicable for the premixed combustion.

Sincerely, Jinwook

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Old   February 25, 2003, 04:33
Default Re: Fluent and turbulent combustion
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lulu
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Which model in fluent is suitable to catalyst regenerating in fcc process ?thanks
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Old   February 25, 2003, 05:09
Default Re: Fluent and turbulent combustion
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Daniel
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Thanks, Jinwook,

I am interested in particular in a problem where both kinetics and turbulence are important, how does Fluent treat this? are the relevant times added or is there another procedure?

Daniel
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Old   February 27, 2003, 10:08
Default Re: Fluent and turbulent combustion
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cg
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The latest version of Fluent (6.1) can treat finite rate effects in turbulent flames. You can use any chemical mechanism, and there are two models for turbulence-chemistry interaction, viz. the EDC model and the PDF Transport model. Fluent also uses ISAT which speeds up the chemistry calculations up to a thousandfold, which can make full kinetic simulations in flames affordable.
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Old   March 2, 2003, 06:03
Default Re: Fluent and turbulent combustion
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Daniel
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As far as I know, both the EDC and the PDF transport methods assume that chemistry is fast when compared to turbulence. This is not the case in my problem. Can Fluent treat slow chemistry interactions as well?

Thanks, Daniel
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Old   March 7, 2003, 09:07
Default Re: Fluent and turbulent combustion
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cg
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Both EDC and PDF Transport are turbulence- chemistry interaction models for arbitrary chemical mechanisms. So, the chemistry can be slow as a snail!

The names are confusing. EDC is a completely different model to the Eddy-Dissipation model, and PDF Transport is a completely different model to the PDF model (now called the Non- Premixed model in Fluent 6).
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