species mass fractions

Mark Austin

Hi,

I am using 4 species in my flow (CO, H2, CO2, H2O). I also have a source and sink for these sources as one of my domains (very thin, 1 layer of elements deep, along a wall). Water vapour is expected to be the most abundant species, so it is not defined explicitly at the inlet, or in the source/sink.

When I go to view a cross section of my flow to look at species contours, I find that the H2O countour has a suspicious appearance. The contour seems to almost interpolate from whatever the mass fraction is in the flow to zero on the elements at the wall. These are my source/sink elements. CO, CO2, and H2 have contours that are orthogonal to the wall, as expected, but water vapour seems to want to interpolate. I have also done a volume average of the mass fractions in the source/sink region and have found that they do not add up to 1, whereas in other regions they do add up to 1.

Any ideas would be appreciated. Thanks Mark