Effects of heated block comprised porous stratum and micropolar hybrid nanofluid on convective heat transfer and entropy generation in a square enclosure

Abstract

AbstractA numerical study is performed to explore the effects on heat convection and entropy gthe eneration due to porous stratum and heated block in an enclosure saturated with micropolar hybrid nanofluid. Constant heat flux through half of the length of the square enclosure is centrally placed at the bottom wall and the top wall is isothermally cooled while vertical walls are insulated. The Cu‐Al2O3/water hybrid nanofluid is considered a micropolar fluid (MF) with constant physical properties. The Boussinesq approximation is implemented on the density variation and convection within the porous layer is regulated with the Darcy–Brinkman model. The governing nondimensional equations are solved with the finite difference method (FDM). Effects of various key parameters on isotherms, streamlines, local Nusselt number, and average Nusselt number are discussed numerically and analyzed through graphs. The entropy generation analysis (EGA) has been done with local and average Bejan numbers, local entropy generation, and entropy generation numbers. The heat convection from the heat flux enhances with the increase in the volume fraction of the hybrid nanoparticles (), Rayleigh number (Ra), and Darcy's number (Da) while attenuating by increasing the vortex viscosity K0. The domination of the heat transfer irreversibility over the frictional irreversibility upraises with K0 and . With an increase in the porous stratum's thickness, the average value of the Bejan's number enhances, and a decline in the entropy generation number Ns.