reacting flow, inert component
 

Hi

I'm a beginner in modeling reaction in Fluent. If you have gas mixture of hydrocarbons reacting on catalyst, do you consider Nitrogen as the inert and most abundant component in your mixture(for mass conservation purpose)? if yes, for your inlet condition ,do you have to give the highest mole fraction to Nitrogen? if yes ,then it effects the diffusivity of the mixture, while in reality we don't run the experiment with Nitrogen. I have steam and hydrocarbons doing the reforming reaction. Advice is appreciated!