Multiple steady flows in confined gaseous double diffusion with discrete thermosolutal sources

摘要

A detailed numerical study has been conducted to investigate the steady natural convection in a binary mixture in rectangular enclosures with the simultaneous presence of discrete heat and moisture sources. The Prandtl number and Lewis number used are 0.7 and 0.8, respectively. The heat and mass transfer characteristics of the horizontal enclosure are analyzed using the heat lines and mass lines, and the heat and moisture transfer potentials are also explained by the variations of overall Nusselt and Sherwood numbers. Numerical results are particularly presented to illustrate the effects of the buoyancy ratio, thermal Rayleigh number, and strip pitch on the multiple steady flow patterns and the associated heat and mass transfer, for both destabilizing and stabilizing solutal buoyancy forces. The effects of the buoyancy ratio are found to be rather significant on the flow pattern and heat and mass transfer especially for the destabilizing solutal forces. Additionally, in the regime that both thermal and concentration buoyancy forces are destabilizing, the heat and mass transfer potential can be promoted or inhibited, depending strongly on the thermal Rayleigh number and strip pitch. (C) 2007 American Institute of Physics.