
For species transport calculations, there are two ways to model the diffusion of chemical species. For most applications the Fick's law approximation is adequate, but for some applications (e.g., diffusiondominated laminar flows such as chemical vapor deposition), the full multicomponent diffusion model is recommended.

The full multicomponent diffusion model is enabled in the
Species Model panel. Also, note that the full multicomponent diffusion model is computationally expensive.
