Combustion kinetic model
 

I wish to simulate a methane / air combustion system by CFD. We have a simulation package including a commercial CFD package interfaced to CHEMKIN and our own radiation solvers. We need to have the appropriate chemical kinetics mechanism.

I am aware of "full" mechanisms (e.g., GRI-MECH) in which tens of species and hundreds of elementary reactions are available. However it seems impractical for calculation. Moreover, it seems to me an "overkill" if we merely wish to have the correct final composition and temperature and a crude estimate of the developing combustion.

I assume there are well-established simplified mechanisms used in combustion research, where few (or even a single) reactions are used with reasonable accuracy. Can anyone here suggest such sets with their rate equations and coefficients (preferably with authoritative reference)?

Thanks, Rami

Re: Combustion kinetic model
 

The combustion literature is full of simplified mechanisms. Try browsing "Combustion and Flame" and any recent proceedings of the Combustion Institute's International Symposium on Combustion. These should be available in any decent research library. Finding mechanisms is easy. The hard part is figuring out which ones are worth using for your particular application because many of them are valid over only a small range of parameter space (equivalence ratio, initial temperature, pressure, diluents, etc.).

Re: Combustion kinetic model
 

Thank you, Dean,

I was aware of these resources. The reason I have posted my query was because I wished experienced combustion experts' specific advice what is considered as "standard kinetics models" in methane combustion in air for the purposes mentioned in my original posting.

Since you suggested that most models are limited by their validity range, I'll try to narrow it somewhat: We wish to work in pressure range of roughly 5-20 bars and initial temperature range of 900-1500K. The equivalence ratio is still undetermined. We do not consider any additional diluents, except - of course - the nitrogen in the air. We are currently not trying to cope the NOx formation, just the (spontaneous) ignition, the development region and the final temperature and composition.

Rami

Re: Combustion kinetic model
 

Rami, There are several simplified mechanisms for CH4 combustion in the literature. There is a 4step, 7 step, and something like a 16 step mechanism - these all come with their own reduced reaction rate formulations and contain far fewer species. For these look up papers by Norbert Peters, (I think he is at Stanford now) and J.-Y Chen (UC Berkley ?) . One paper that has the 4 step mech :

N.Peters, "Reducing Mechanisms ", In M.D.Smooke, editor, Lecture Notes in Physics, Springer-Verlag, 1991.

Theres more, I can dig them up if you want. Regards Srinivasan

Re: Combustion kinetic model
 

Thanks Srinivasan,

> Theres more, I can dig them up if you want.

Yes, please.

Thanks a lot, Rami

Re: Combustion kinetic model
 

Try here:

http://www.ca.sandia.gov/TNF/chemistry.html

May be helpfull.

Mario

Re: Combustion kinetic model
 

Thanks a lot, Mario.