Experimental and Numerical Investigation of Melting in the Presence of a Magnetic Field: Simulation of Low Gravity Environment

Abstract

An experimental and numerical study is presented on melting behavior of a pure metal in the presence of a static magnetic field. When a transverse magnetic field is present and the working fluid is electrically conductive, the resulting Lorentz forces will dampen the convective flows. Buoyancy driven flow is the focus of this study. Hartmann number, a dimensionless parameter proportional to the strength of magnetic field, dominates the convection flow suppression. The effects of the magnetic strength on melting rate and on the profile of solid/melt interface are studied. The experiments are conducted with pure Gallium as phase change material (PCM) inside a rectangular test cell. The solid/melt interface at the side center position is measured by an ultrasound device and its profile is mapped via the florescent light shadowgraphy. Temperature measurements and volume expansion/contraction tracking are used to verify the experimental result. The results show that the magnetic strength has a remarkable effect on the melting rate and the interface profile. The numerical simulation fits very well with the experimental data especially, at larger Hartmann numbers.