Hydro-Magneto-Thermal Performance and Irreversibility Analysis of Copper and Aluminium Oxide Based Nanomaterial Inside an Octagonal Enclosure

The current study aims to explore the influence of magnetic field on the buoyancy driven flow behaviour of hybrid nanomaterial within an impermeable, rigid octagonal enclosure which consists of a heated circular cylinder. The rectangular fins of variable lengths are attached to the circular cylinder. The considered nanomaterial within an octagonal enclosure is copper and aluminium nanoparticles suspended in water (Cu–Al 2 O 3 /H 2 o). Further, boundary configurations are that the horizontal (lower and upper) walls of an octagonal cavity are kept at high temperature, the vertically walls remain at low temperature and rest inclined walls are insulated. Numerical simulations are carried out on the non-dimensional governing equations by implementing the Finite Element Method (FEM) incorporating Galerkin algorithm in robust COMSOL-MULTIPHYSICS software. The velocity field, entropy generation, temperature, Nusselt number, and Bejan number are simulated via streamlines and isotherms. The impact of significant parameter like Hartmann number (0 ≤ Ha ≤ 100), heat generation parameter (0 ≤ Q ≤ 20), Rayleigh number (10 3 Ra ≤ 10 6 ), and size of the fins (H = 0.07, 0.12, 0.17) are also analysed. The current findings are straightly relevant to thermal management systems viz. compact heat exchangers, electronic device cooling, and solar thermal collectors, where minimal irreversibility & efficient heat dissipation are crucial as the heat dissipation and irreversibility are explored in the study. Model validation confirms the reliability of the numerical approach. It is found from the study that the temperature within an enclosure is enhanced with a rise in the size (H) of the fins. Entropy reduces with an increase in Hartmann number Ha and size of fins which is favourable case for thermal storage system. The average Nusselt number is a decreasing function of Ha and Q and an increasing function of Ra.