I've been using the single step chemistry model for methane combustion for quite long and along with the segregated solver, have been successful in simulating unsteady laminar combustion processes.

I tried using the two step model, but wasn't able to ignite the premix charge. didn't turn on backward reactions. even though the interest region is lean premix combustion, I tried a stoichiometric mixture so that the ignition process would be easier.

suggestions from the CFD gurus please! need to work with multiple step chemistry, and starting with a 2 step model is definitely in my agenda.

did you turned on :

cp ( mixture ) = mixing law

cp ( every species ) = piacewise - polinomial

?? Try, along with setting for viscosity and density

Marc

I have run into similar problems. I've used two different ways to get the combustion going:

1 - Initialize flow field with temperatures higher than auto-ignition temperature.

2 - Start using the eddy-dissipation model only. This will burn the fuel instantly as it mixes with the oxygen. Later turn on Magnussen model to include kinetics.

[J.F]

Did you finally get a solution to your problem?
I am finding a similar problem,

Thank you very much