Confined Non-Newtonian Fluid Flow and Heat and Mass Transfers Induced by both Thermal and Solutal Buoyancy Forces of Equal Intensities

Abstract

In this paper is reported an analytical and numerical study on double-diffusive natural convection in a non-Newtonian power-law fluid confined in a shallow horizontal rectangular enclosure submitted to uniform heat and mass fluxes along its short vertical sides, while the horizontal ones are insulated and impermeable. Here, the cases of aiding and opposing thermal and solutal buoyancy forces of equal intensities are considered. In the first part of the work the full governing equations are solved and the effects of the power-law behavior index, n, and the generalized thermal Rayleigh number, RaT , are examined and analyzed. In the second part, an analytical solution, based on the parallel flow approximation valid in the case of a shallow cavity, is proposed and an excellent agreement of results between the two approaches is observed, which validates them mutually.

Keywords

• Double-diffusive natural convection; Heat and mass transfers; Non-Newtonian fluids; Rectangular shallow enclosures