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Daniel February 24, 2003 03:25

Fluent and turbulent combustion

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?


Jin-Wook LEE February 24, 2003 05:44

Re: Fluent and turbulent combustion
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

lulu February 25, 2003 04:33

Re: Fluent and turbulent combustion
Which model in fluent is suitable to catalyst regenerating in fcc process ?thanks

Daniel February 25, 2003 05:09

Re: Fluent and turbulent combustion
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?


cg February 27, 2003 10:08

Re: Fluent and turbulent combustion
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.

Daniel March 2, 2003 06:03

Re: Fluent and turbulent combustion
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

cg March 7, 2003 09:07

Re: Fluent and turbulent combustion
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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