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Old   September 30, 2003, 09:19
Default two-step mechanism
  #1
eric
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Hi,

I want to simulate methane/air combustion with the eddy dissipation model. But i want to use a two-step mechanism.

I know where to input the reaction, i.e. materials/reaction/edit/total number of reactions.

What i want to know is what values/reactions do i put in here? I really do not have any idea what to do.

Can anyone help??

Thanks,

Eric
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Old   September 30, 2003, 10:41
Default Re: two-step mechanism
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Ale
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In the Materials panel, click on the Database button, and select the methane-air-2step mixture. Copy it to your mixtures' list and select it as your mixture. Now you're ready to use it in your eddy-dissipation model.

Regards,

Ale
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Old   September 30, 2003, 12:16
Default Re: two-step mechanism
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eric
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Thanks Ale,

The reason i want to use the two-step mechanism is to account for the intermediate species in the combustion. So that i get a more accurate temperature field and species concentrations in the results.

Is this right?

What is the advantage of using the two-step mechanism???

Thanks

Eric
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Old   September 30, 2003, 20:38
Default Re: two-step mechanism
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Jin-Wook LEE
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If you want to account for one intermediate species, e.g., CO, two step mechanism is enough. But if you want to account for many intermediate species, you should use mixture-fraction/PDF model.

Multi-step mechanism, of course, can increase the accuracy of the simulation. But more important one is more accurate reaction parameters, which are, in general, not universal constants, but mostly system dependent.

Sincerely, Jinwook
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