Konstantine Kourbatski
Ansys Employee
I was more interested in seen a contour plot of mass fraction with node values off, but this is also good. So cell centered values of adjacent to the wall cells show a mass fraction variation which is consistent with mole fraction distribution, as it should be. So what you were observing is a post-processing artifact. In general, when Fluent post-processes with node values on, it interpolates from cell centers to the nodes. If a quantity is defined at a boundary, e. g. no-slip velocity or mass fraction of species as in your case, then this exact distribution is displayed instead of interpolated values. Apparently, R16, which is very old version, displays interpolates mole fraction values, but shows exact mass fraction. This was made consistent in newer releases. n