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-   -   Re Radiation (http://www.cfd-online.com/Forums/fluent/27519-re-radiation.html)

Guosheng Kang February 23, 2000 18:04

Re Radiation
 
Hello, I am solving a combustion problem, in which P-1 model is used for radiation. The combustion system is methane-air, but in my problem, some oxygen is added to the air, which is the so called "Oxygen Enriched Air". I copied the methane-air data just from the database, however, the default Absorption Coefficient is zero(1/m) and the Scattering Coefficient is zero (1/m), too. These two coefficients should be non-zeros when P-1 model is used, I hope some experts are there to give me a clue. Thank you for response.

Guosheng

Jouni Valtatie February 24, 2000 02:35

Re: Re Radiation
 
Hi!

There should be in the drop down list beside the absorption coefficient options: WSGGM-domain-based and WSGGM-cell-based (Weighted Sum of Grey Gases Model). Choose one of these and your model will compute composition dependent absorption coefficient. Check your manual for details. Basically you should choose domain-based if you are more interested in overall heat transfer into domain boundaries, cell based if you are more interested in the inner behaviour of the flame.

I think that in gas combustion it is safe to leave the scattering coefficient to zero, because there shouldn't be particles, which produce scattering, but check your manual for details.

Best Regards,

Jouni

Guosheng Kang February 27, 2000 23:52

Re: Re Radiation
 
Thanks Jouni, I tried as you suggested, it works better now. Talk to you later, seems another issue is of concern.

Guosheng


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