Mixed convection by buoyancy and magnetothermal forces

Abstract

The magnetic force in the paramagnetic fluid depends on the local gradient of magnetic flux density and the temperature-dependent magnetic susceptibility. In the presence of the gravity, the buoyant force due to the temperature difference additionally overlaps, and the resultant flow becomes a mixed convection. In this study, the effect of the temperature-dependent magnetic force (magnetothermal force) on the natural convection was numerically investigated. The magnetic field formed by the permanent-magnet array was employed and effective one was discussed in terms of the heat transfer. A three-dimensional Rayleigh-Benard convection simulation was conducted with the magnet array below the bottom hot wall. It was found that the magnetothermal force enhances the convection not only where the magnet locates but also away from the magnet due to the force profile.