Relationship between Applied Static Magnetic Field Strength and Thermal Conductivity Values of Molten Materials Measured Using the EML Technique

摘要

In order to quantitatively investigate the effect of convection in an electromagnetically levitated molten iron droplet on the thermal conductivity of the droplet measured by the electromagnetic levitation (EML) technique in the presence of a static magnetic field, numerical simulations of the melt convection in the droplet and measurements of the thermal conductivity with the periodic laser heating method were carried out. In addition, the thermal conductivity of molten iron was measured by the EML technique, and then compared with values obtained numerically. It was found that the numerical simulations could sufficiently explain the measurement of thermal conductivity by the EML technique in a static magnetic field. It is suggested that a static magnetic field of 10 T is enough to measure the real thermal conductivity of molten iron by the EML technique. Moreover, the correlation between the static magnetic field and the contribution of melt convection to the measured thermal conductivity was investigated by using a nondimensional parameter, which is the ratio of the electromagnetic force operated by the static magnetic field to that produced by the alternating current in the RF coils.