Triple convective-diffusion boundary layer along a vertical flat plate in a porous medium saturated by a water-based nanofluid

•Porous medium is filled by a water-based nanofluid and two salts.•Plate is cooled convectively by a fluid.•The effects of Brownian motion and thermophoresis parameters are included.•The heat transfer rate increases with volume fraction of nanoparticles and salts.•The Brownian motion has negligible effects on reduced Nusselt number.

In this article, we investigate steady triple convective-diffusive boundary layer free convection flow past a vertical flat plate embedded in a porous medium filled by a water-based nanofluid and two salts. 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 in to account in the boundary condition. The effects of Brownian motion and thermophoresis parameters are also introduced through a Buongiorno model in the governing equations. The self-similar solutions are obtained numerically using an implicit finite difference method. 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. Furthermore, it is also shown that the Brownian motion has negligible effects on reduced Nusselt number.