[Cerbadave]

Hi everyone,

I am using the Fluent species transport model to solve a non-reactive diffusion problem in a turbulent flow of a h2-ch4 blend in air. What I realized is that the effective diffusion coefficient for every species is equal through the entire domain, so that h2 and ch4 mix with air in the same way. That seems to me quite unrealistic.
I tried to change the settings in terms of mass diffusion coefficient of every species, but obviously the eddy diffusivity term overwhelms the laminar one, so it does not have any influence on that.
Does this mean that with this model every species diffuses in the same way based on the eddy viscosity of the flow field?

Thank you