Abstract: As a highly efficient heat transport medium, the study of the melting and heat transfer characteristics of metallic fluids in phase change processes under magnetic fields is of great importance for industrial processes such as fusion reactors, electromagnetic metallurgy, and additive manufacturing. In this paper, the melting process of metallic gallium under a strong magnetic field was studied by building a comprehensive experimental system for heat transfer through phase change of metal, and the heat transfer characteristics of metallic gallium melting under the action of a magnetic field were obtained. The dynamic average distance of the heated wall from the phase interface during melting instead of the fixed characteristic length is used to study the variation of the relative strength of convective heat transfer and thermal conductivity with Fourier number (Fo) during melting. The results show that: at a small Hartmann number (Ha), the melting has a melting-promoting effect at the early stage and is inhibited at the later stage; at a large Hartmann number the magnetic field has an inhibiting effect on the convection during the melting of gallium metal, and the melting process shows a laminar and uniform advance. The magnetic field reduces the height of the dominant zone of thermal conductivity at the bottom of the cavity during the melting process and suppresses temperature fluctuations during the melting process, resulting in a uniform temperature distribution during the melting process.

Key words: Uniform magnetic field, Melting heat transfer, UDV, Liquid metal