Thermo-diffusion and diffusion-thermo effects on MHD free convection flow past a vertical porous plate embedded in a non-Darcian porous medium

Abstract

An analysis is presented for the steady free convection heat and mass transfer past a vertical porous plate in a non-Darcy porous medium subjected to uniform magnetic field with Soret (thermo-diffusion) and Dufour (diffusion-thermo) effects included. The non-Darcy effects are simulated via second order Forchheimer drag force term in the momentum boundary layer equation. The governing boundary layer equations are transformed into a non-dimensional form and the resulting non-linear system of partial differential equations are solved using the efficient Keller-box implicit numerical finite difference method. Increasing magnetohydrodynamic body force parameter ( M) is found to decelerate the flow. Increasing Soret number and simultaneously decreasing Dufour number enhances the local heat transfer rate (local Nusselt number) at the plate surface with the opposite effect sustained for the mass transfer rate (local Sherwood number). Increasing Forchheimer inertial drag parameter ( Λ) retards the flow considerably but enhances temperatures. Increasing Darcy number accelerates the flow due to a corresponding rise in permeability of the regime and concomitant decrease in Darcian impedance. Applications of the model arise in metallurgical materials processing, chemical engineering flow control, geothermal hydromagnetics, etc.