What might be the reason for C2H2/air flame temperature being too high (over 3300 K). I am using 1 global reaction mechanism with eddy-dissip/finite rate model. Adiabatic flame temperature for this mixture should be 1000K lower. Also, CO and H2O do not converge. The geomery and the physics of the problem are very simple.

Heat capacity of gases not set to be a function of temperature?

Thank you !

These basic models normally over predict the flame temp.

Non-smooth transitions between coarse and dense mesh regions, or highly skewed elements are the usual reasons for poor convergence - OR NON-REALISTIC PHYSICS STRUGGLING TO SATISFY THE FUNDAMENTAL EQUATIONS. This is usually caused by getting the boundary conditions wrong or adding walls you don't notice.