mix 2 materials using COMSOL Multiphysics
 

Hi,
I need to mix two liquids using 2 inlets with different materials in each and 1 outlet. I am new in CFD and I am not sure if I should use twice the physics "transport of diluted species" for the mixing; one for each material. Regarding the fluid flow should it be again in the same way? Since the parameters for the 2 materials (viscosity, density) are not identical?
Thanks a lot.