Triple diffusive free convection along a horizontal plate in porous media saturated by a nanofluid with convective boundary condition

The steady triple diffusive boundary layer free convection flow past a horizontal flat plate embedded in a porous medium filled by a water-based nanofluid and two salts is investigated numerically. The plate is assumed to be convectively cooled by a surrounding fluid. It is assumed that there is no nanoparticle flux at the surface and the effect of thermophoresis is taken into account in the boundary condition. The effects of Brownian motion and thermophoresis parameters are also introduced through Buongiorno model in the governing equations. Using appropriate similarity variables, the partial differential equations are transformed to ordinary (similarity) equations, which are then solved numerically using an implicit finite difference method with quasi-linearization technique. The effects of the buoyancy ratio, regular Lewis numbers and modified Dufour parameters of both salts and nanofluid parameters on the flow and heat transfer are investigated. It is found that the heat transfer rate increases as we include nanoparticles and salts. (C) 2013 Elsevier Ltd. All rights reserved.