Non-Newtonian effects on MHD thermosolutal free convection and entropy production of nanofluids in a rectangular enclosure using the GPU-based mesoscopic simulation

Abstract

Magnetohydrodynamics (MHD) thermosolutal natural convection flow of power-law based non-Newtonian nanofluids within a rectangular chamber has been examined by Graphics Process Unit (GPU) based meso-scale multiple-relaxation-time (MRT) lattice Boltzmann method (LBM). The chamber is filled with Copper (Cu)–Water nanofluids. The vertical walls are twice the horizontal length of the enclosure. The vertical walls have two different uniform temperatures and concentrations, and the top and bottom walls with zero gradients of temperature and concentration. The LBM simulation has been conducted to examine the effect of Rayleigh number (Ra), the shear-thinning (n<1), Newtonian (n = 1) and shear-thickening (n>1) fluids, Hartmann number (Ha) and nano-particle volume fractions (0%–5%). Results show that an increment of the power-law index (n) decreases the average Nusselt number () and the Sherwood number (). Increasing the volume fractions of nanoparticles causes an increase in and a decrease in . New correlations for and have been proposed for valid for . Finally, a detailed entropy production of the study has been presented and analyzed.