ON SINGULAR BOUNDARY CONDITIONS IN MASS TRANSFER ACROSS RECTANGULAR ENCLOSURES

Abstract
In modeling mass transfer across rectangular enclosures one is confronted with singular velocity boundary conditions at the geometrical corners of the enclosure. Solutions to such a problem obtained, e.g., from a finite difference scheme, may then depend on the particular way the singularities are handled. The uncertainty in the solutions is studied for a vapor crystal growth sample case, by comparing results obtained in two extreme codes, corresponding to slip and non-slip, respectively, at the corners. It is found that (within the realm of the model used) the total mass transport across the enclosure, the sublimation and the condensation fluxes at the interfaces, and the concentration profile are unaffected by the choice of codes. The velocity field, however, is affected adjacent to the singularities.