Entropy generation due to hydromagnetic buoyancy-driven hybrid-nanofluid flow in partially heated porous cavity containing heat conductive obstacle

Abstract

Hydromagnetic natural convection heat transfer in an improved designing has sustainable importance in high performance thermal equipment and geothermal energy systems. This investigation explores the fluid flow and temperature behaviours along with entropy generation for buoyancy driven flow of hybrid nanofluid in a partially heated cavity saturated by porous medium having heat conductive cylinder in presence of external magnetic field. Effective thermal conductivity model is formulated based on Brownian motion of Cu and Al2O3 nanoparticles. The developed governing equations are solved implementing Galerkin finite element method. Results-based discussion is presented through streamlines, temperature contours, heat transfer rate and entropy generation tools, respectively. The results endorse that fluid flow and temperature and also local entropy generation are phenomenally influenced with higher buoyancy parameter but these impacts are correlated with magnetic field strength, amount of hybrid nanoparticles and also cavity permeability. The heat transfer rate and average entropy generation components are increased with the increase in Rayleigh number and these trends are expedited with the increase in cavity porosity and volume fraction but reverse trend is found for magnetic field effect except magnetic-irreversibility. In addition, Bejan number is declined for increasing Rayleigh and Darcy numbers but increased for higher Hartmann number and amount of hybrid nanoparticles.