2 Phases with same parameters, any diffusion?
 

Hi!

I’m struggling with what seems to be a pretty basic problem. I’m simulating a wash out kinetic in a fluidic device, I want to see how phase 1 is replaced by new injected phase 2. Both have the same physics, both of liquid water at the same temperature. My question is now if there is any diffusion? Or did I basically switched those off because I used for both phases the same properties?

Kind regards
Kai

Model dependent
 

Hi

That depends on the model used. if both the fluids belong to same phase as multiple species or components, then by default there is a diffusion coefficient applied. You may set it to very small value. If both fluids are treated as separate phases, then there is no diffusion by default since that would require mass transfer in the phase interaction.