Investigation of the optimum design of magnetic field arrangement to enhance heat transfer performance of Fe3O4-water magnetic nanofluid

Abstract

In this study, numerical simulations were conducted to explore the best possible magnetic field arrangement that can maximize the heat exchange performance of Fe3O4-water magnetic nanofluid. Orientation of magnets poles, number of magnets, and the distribution of magnetic field intensity over the flow path are studied to obtain the optimum design which is then tested at various values of magnetic nanoparticles volume fraction, magnetic flux density, and Reynolds number. Results indicated that the optimum design is achieved by placing magnets with N–N orientation and adjusting the magnetic flux density to increase by a rate of 100% between each two successive magnets along the path of the flow. Results also revealed that the average Nusselt number and pressure drop increase when the magnetic flux density is increased. Furthermore, it was found that the effect of increasing magnetic nanoparticles volume fraction on the heat transfer performance is higher at low Reynolds number. An increase of the average Nusselt number in the range of 16.44%–24.46% compared to the design without magnetic field was achieved when using the optimum design with an average magnetic flux density of 1000 Gauss, and magnetic nanoparticles volume fraction of 4%.