MHD thermosolutal natural convection and entropy generation of Carreau fluid in a heated enclosure with two inner circular cold cylinders, using LBM

Abstract

In this paper, thermosolutal natural convection and entropy generation in a heated enclosure with two inner cold cylinders filled with a non-Newtonian Carreau fluid in the presence of a uniform magnetic field has been simulated by Lattice Boltzmann Method (LBM). This study has been conducted for certain pertinent parameters of Rayleigh number (Ra=104 and 105), the Buoyancy ratio (N = −1, 0.1, 1), Hartmann number (Ha = 0, 15, 30, 60, and 90), power-law indexes (n = 0.2, 1, and 1.8). Results indicate that the rise of Rayleigh number enhances heat transfer for various studied parameters. The increase in power-law index provokes heat and mass transfer to drop gradually. However, the effect of power-law index on heat and mass transfer declines steadily as Hartmann number rises. The enhancement of Hartmann number causes heat and mass transfer to decline significantly. The augmentation of the buoyancy ratio number enhances heat and mass transfer. The augmentation of Rayleigh number enhances different entropy generations and declines the average Bejan number. The increase in the power-law index provokes various irreversibilities to drop significantly; although, the increase in Hartmann number decreases the influence of power-law index on different entropy generations. The enhancement of the buoyancy ratio causes the summation entropy generations to increase considerably. It was found that the total entropy generation declines as Hartmann augments.