Methane combustion in gas burner

Stefano

I'm trying to model a methane-air combustion process (turbulent)in a burner. This model consist in an orifice from which methane flows, a venturi where the methane air mixture is created (primary air inlet) and a series of orifices with secondary air mixing and combustion. I have tried many combustion models (EDC, FRC and combined EDC/FRC) but none of them gives a meaningful result (depending on the model there is no ignition or, on th contrary, the mixture ingnites inside the venturi and not outside the oulet orifices). Does anyone have some good advice?