Two-phase modeling of the effect of non-uniform magnetic field on mixed convection of magnetic nanofluid inside an open cavity

Abstract

In the present paper, the effect of a non-uniform magnetic field on the mixed convection heat transfer of magnetic nanofluid (water-Fe3O4) flow in an open cavity is studied. Current-carrying wires are used as a magnetic field. Momentum equations and Buongiorno's two-phase model are modified by adding the Kelvin force and magnetophoresis terms, respectively. The effect of changing various parameters such as Magnetic number (0≤Mn≤5 × 107), Reynolds number (Re=200, 400, 600) and horizontal distance of wires from cavity walls on the flow pattern, nanoparticle volume fraction distribution, and the average Nusselt number have been investigated. The results showed that applying a non-uniform magnetic field on the magnetic nanofluid flow, due to the effect of Kelvin force, changed the flow pattern and created the new vortices in the fluid flow. By applying a weak magnetic field (up to Mn=5 × 106), the average Nusselt number decreased, and with increasing the magnetic number the average Nusselt number increased significantly. The highest enhancement of the average Nusselt number was obtained with 57.07%.