Conjugate natural convection and entropy generation under uniform magnetic field in a partitioned square cavity filled with two different nanofluids

Abstract

The present study performs a numerical investigation of conjugate natural convection heat transfer and entropy generation in a square cavity under uniform magnetic field having a heat conducting sinusoidal vertical partition at the mid-section. The solid partition divides the cavity into two symmetric convection regimes, which are filled by two different nanofluids, namely Al2O3-water and CuO-water respectively. The right and the left walls are kept at two different constant temperatures, whereas the top and the bottom walls are kept adiabatic. The present problem is mathematically modeled by two-dimensional continuity, momentum and energy equations for the convection domain and conduction equation for the solid partition. The governing equations in non-dimensional form are solved by Galerkin finite element method with triangular discretization system. Characteristics of conjugate natural convection heat transfer and entropy generation are investigated for different values of Rayleigh number based on base fluid (water) within the range of 103 ≤ Ra ≤ 109 and various choice of Hartmann number (0 ≤ Ha ≤ 100). Effects of these parameters have been assessed in terms of isentropic plots corresponding to both thermal irreversibility and fluid frictional losses, heatline plots, average Nusselt number along the hot wall, average entropy generation and average Bejan number in the left convective domain. Computational results suggest that both Rayleigh and Hartmann numbers significantly contribute to the performance of heat transfer and entropy generation inside the cavity.