The Inflow node adds a boundary condition for an inflow boundary, where the concentration for all species is specified in the manner of
.
Specify the concentration ci (SI unit: mol/m
3) of each species individually by entering a value or expression in the corresponding field.
The option Concentration constraint constrains the concentration values on the boundary by the use of pointwise constraints.
The other option, Flux (Danckwerts) can be used when the concentration at the boundary is not known, or when it varies in a nontrivial manner. This may, for example, be useful when reactions with high reaction rates occur in the vicinity of the inlet. In this case the concentration far upstream of the boundary is instead prescribed. The
Flux (Danckwerts) condition prescribes the total flux defined by the upstream concentration and the fluid velocity at the boundary.
) and select Advanced Physics Options in the Show More Options dialog box.