# Species Source Terms on Navier-Stokes Equation (Reacting Flow)

I have a quick question: if i decide to model two reactants (for example kerosene+oxygene) and they have their own NS equations separately (own velocity, density, temperature). For this case, should the reactions source be included on the continuity equation?

• There is not a separate NS equation for each species. The combination of the various species satisfies one overall NS equation. Movement of species relative to the mass average velocity is described by the diffusion equation. – Chet Miller Feb 16 '18 at 4:30