Thanks for your answers and apologies for the late reply, I am really not familiar with the physics of combustion and wanted to review a few things before asking for some more help.


My mole fractions from before are wrong but I was wondering where the 21% came from. So for air it would be 1/(1+3.76) = 0.21

But shouldn’t the mole fraction for the case where I have CH4 as well be calculated as

2/( 1 + 2 + 2*3.76) = 0.19 for O2

1/( 1 + 2 + 2*3.76) = 0.095 for CH4



I fixed the turbulent intensity using this formula

It is now about 14 %


Regarding the flame, I asked on the learning hub before which model I should be using and they said that since my actual system does not have a flame, I could model it with the species transport model.