Computational Investigation on Flow Dynamics and Heat Transfer of Nanofluid in Low Reynolds Number Under Magnetic Field

Abstract

The effect of magnetic field on the heat transfer enhancement and pressure drop is studied numerically. A water based Fe3O4 nanofluid (2 Vol%) is flowing in a 2-dimensional heated channel at low Reynold’s number (Re = 150 - 250) and different magnetic field intensities ranging from 1200 G to 2000 G are applied. The heat sink with dimensions of 40 mm (L) X 4 mm (H) consists of magnets placed at four different locations. The magnetic field is acting as a vortex generator which enhance heat transfer for highly concentrated heat fluxes. The heat transfer enhancement due to the magnetic field at x = 25 mm is studied. Results showed that there is an improvement of maximum 26% in heat transfer using magnetic nano fluid with magnetic field as compared to pure water. This value grows to around 35% when a magnetic field of strength 1200G is applied and even around 200% at magnetic field of strength 4000G as compared to pure water. However, this enhancement comes with an increase of pressure drop and back flow. This can be explained due to formation of vortices due to the turbulence caused by the sudden force of magnetic field. The optimum condition is obtained at magnetic field of strength 2000 G with a heat transfer enhancement of around 70%.