Numerical modeling of magnetohydrodynamic thermosolutal free convection of power law fluids in a staggered porous enclosure

Abstract

In this study, the influence of a magnetic field on thermosolutal free convective flow inside a staggered porous enclosure, filled with non-Newtonian power-law fluids is investigated using the Galerkin finite element method. The computational model has been validated against available data from the literature. Results indicate that the augmentation of Hartmann number (Ha) causes heat and mass transport to decrease significantly. However, the magnetic field has a greater influence on mass transfer in comparison with heat transfer. The maximum local Nu and Sh numbers are decreased respectively by 55% and 43% at Ha = 75. This reduction becomes more significant for Hartmann number values higher than 25. However, the increase of Darcy number reduces the influence of the magnetic field. In the presence or absence of magnetic field, the alteration of power law index provides different trends for the prediction of the convective flow intensity. The increase in Lewis (Le) number has a smaller effect on the heat transfer rate compared to the mass transfer rate. Increase in Le augments mass transfer rate by 230% but decreases heat transfer rate by 37%. Further, the augmentation of the buoyancy ratio causes a significant increase in the heat and mass transfer rates.