Numerical Simulation of Thermosolutal Convective Transitions in a Very Narrow Porous Annulus under the Influence of Lewis Number

Abstract   This paper reports on the natural convection within a very narrow horizontal annular cavity filled with a porous medium saturated by a binary fluid. The main objective of this study is the identification of the effect of Lewis number on the flow structure and on the heat and mass transfer rates, in a cavity of very small radius ratio R = 1.05, in the case of equal buoyancy forces (N = 1), for a Rayleigh number Ra = 50. The dimensionless governing equations were solved by the centered Finite Difference method using the ADI scheme. Several multicellular flows appear during the variation of the Lewis number, resulting in a direct impact on the heat and solutal transfer rates.