STARCD: combustion problem involving multi-component mixing
 

Hi!
I'm trying to implement a combustion model of syngas-fired model combustor.
I have a problem in defining a fuel consisting of a mixture of gases (CH4,CO,N2,CO2,H2), which enter in the comustion chamber each characterized by its own mass fraction.
If i use a single component fuel (like propane) i have no problems with the simulation. But when i try to use the syngas as fuel, the simulation give me absurds results (but converges).
I think the problem lies in the definition of scalar boundaries, but i don't find it. If someone can help me...
Regards,
Paolo