species mass fraction in combustion simulation
 

Hi everyone,
I'm doing a simulation of methane-air combustion, the problem is that when setting the boundary conditions at the inlet I can't introduce the fraction of nitrogen. It appears in the materials list of the mixture, I don't know what to do. Help!!!
Thanks

Fluent doesnt list the last element in the material pane as it assumes it is the most abundunt and it is calculated as 1 - sum of rest of massfractions

Thanks, really helpful!!!