Influence of a magnetic field on heat and mass transfer by natural convection from vertical surfaces in porous media considering Soret and Dufour effects

The heat and mass transfer characteristics of natural convection about a vertical surface embedded in a saturated porous medium subjected to a magnetic field is numerically studied, by taking into account the diffusion-thermo (Dufour) and thermal-diffusion (Soret) effects. The governing partial differential equations are transformed into a set of coupled differential equations, which are solved numerically using a finite difference method. Dimensionless velocity, temperature and concentration profiles are presented graphically for various values of the magnetic number M and Lewis number Le, and for fixed values of the Dufour number D-f, Soret number S-r and buoyancy number N. Three cases are considered and presented in tables, for the local Nusselt number and local Sherwood number corresponding to Le = 1 and various values of M, N, D-f and S-r. Increasing the value of M increases the local Nusselt number and local Sherwood number. (C) 2003 Elsevier Ltd. All rights reserved.