stoichiometry partially premixed combustion
 

Hello everyone,
I have a question about stoichiometry. I haven't studied chemistry so it's really confusing for me.
I'm working on a CFD case of premixed-combustion with EBU model.
I need to calculate the stoichiometry field and the stoichiometry in inlet, but since I've 3 inlets, I don't know how to proceed. This is new to me, never worked with premixed combustion before.
I have these data :
inlet 1 : the mixture fraction for fresh gas = 0.156, temp = 294 K
inlet 2 : the mixture fraction for burnt gas = 0.0428, temp = 1880 K
inlet 3 : no mixture fraction but a temperature of 291 K
The case was sent to me with just these informations and I really don't know how to deal with that.
At my disposition, I have the mixing rate field, the fresh gas mass fraction field, the mass fraction of the fuel field, the mass fraction of the oxydant field and the mass fraction of the products field. The equation considered is the one of methan with air :
Ch4 + 2(O2 + 3.76/4.76N2) ----> CO2 + 2H2O + 2.3,76N2.
No intermediate species are considered.
I need to represent the stoichiometry-temperature graph.
How can I calculate the mass flow inlet?
Thanks a lot
yorelchr