Problem implementing DETAILED REACTION MECHANISM

Phil

I'm trying to model a gas turbine combustor using a detailed chemical mechanism but when I use the EDC or PDF transport models the flame goes out. The residuals don't drop rapidly to zero reactions but throughout the solution gradually.

I have the outer wall at flame temp but it still goes out, even when using a basic 2-step methane mechanism.

I can't use the usual diffusion flame models as the flame needs to stabilize at the dump expansion at the inlet to the combustor. The usual solution is to use the finite rate/eddy dissipation model but this is inaccurate above 2-step reactions.

Does anyone know of a way to do this? I think premixed researchers may suffer the same problem but they have a model to fix it. Otherwise I'll need to start trying to write a UDF to solve the problem!

ANY HELP WOULD BE VERY MUCH APPRECIATED!!!!!!!!!!!!