Numerical simulation of Al2O3-water nanofluid heat transfer and entropy generation in a cavity using a novel TVD hybrid LB method under the influence of an external magnetic field source

Abstract

In the present study, a novel TVD Hybrid FD-LBM technique is developed to simulate Al2O3-Water nanofluid flow under Buongiorno assumptions. It goes without saying that all explicit numerical schemes suffer from serious stability problems when dealing with low dissipation equations. The simple Single Relaxation Time Lattice Boltzmann method also is not an exception to this rule; that’s why some modern LBM techniques such as Multi Relaxation Time methods are developing day to day. These new techniques add artificial dissipation to the system to keep the oscillating errors of the convective fluxes damped and consequently the numerical procedure stability rises. In this paper, a novel TVD hybrid technique is applied to the Buongiorno model which has relatively low diffusive fluxes in the concentration equation and the flow, heat transfer, and concentration equations are solved in a closed cavity with an elliptic obstacle. Moreover, the influence of an external magnetic field source on the flow and heat transfer rate is studied and the entropy generation of the whole system is investigated. The results revealed that there is a maximum circulation angle for each Ha number which provides relatively higher Nusselt and Sherwood numbers. At these magnetic field angles, Bejan number decreases but they will not necessarily represent the maximum entropy generation points of the system.