mixture fraction

Sheng Chen

Hi, everyone, Recently I finish some codes to simulating diffusion flame of a jet. Because based on infinite chemical reaction rate, I use mixture fraction instead of species equstions. Unfortunately, the flame length is too long comparing to the standard results which results from the false distribution of mixture fraction -- , whatever the exit velocity in jet, the equivalence mixture fraction will approach the outflow boundary. the mixture fraction Z is Z= (Y - Y_o) / (Y_f - Y_o) Y_o and Y_f is the mass fraction of oxidizer and fuel. Could you tell me where can I find free source codes about mixture fraction? I heard that in CHEMKIN there are some examples about it, but I do not find it. Thanks! Best regards