Numerical simulation of magnetohydrodynamics double-diffusive natural convection in a cavity with non-uniform heated walls

Abstract

The fluid flow in a closed domain with heat and mass transfer has enormous applications in thermal engineering. Specifically, the natural convection with fin has applications in cooling electronic devices, automobile engines, solar collectors, etc. So, this research aims to explore the simultaneous aspects of the natural convection flow of heat and mass transfer, as well as the entropy generation in a square cavity with four fins attached diagonally at each corner and a circular object in the center. The enclosure is filled with non-Newtonian fluid and an inclined magnetic field is applied. The left and right walls are heated by non-uniform linear increasing temperature (Th) having higher concentration (CL). The governing equations are first transformed to dimensionless form and then the finite element method is utilized to resolve it. The parameters and inclusion of fins are deeply analyzed to flow particularities. It is inspected that flow is more consistent in the absence of fins giving rise to more heat and mass transport. The maximum entropy is found in the vicinity of fins corners and solid surfaces. Due to non-uniform heating, negative gradients can also be achieved on the heated walls. Parameters impacts revealed that increasing the Hartmann number (Ha) decreases the kinetic energy, heat and mass transfer rate, and entropy generation. Almost three times lesser kinetic energy (K.Eavg) is obtained in the considered range of Ha. The velocity, temperature and entropy generation lead to amplification as Casson parameter (β) is enhanced. The inclusion of fins produces more resistance to fluid motion resulting in lower Nusselt (Nuavg) and Sherwood number (Shavg). The Higher Rayleigh number (Ra) can motivate the velocity and result in smaller Bejan number.