Numerical Prediction of the Accessible Convection Range for an Electromagnetically Levitated Fe₅₀Co₅₀ Droplet in Space

From December 2014, a series of space experiments will be performed to investigate the influence of the convection on the multiphase solidification phenomena of metallic alloys. For the success of the mission, it is of critical importance to predict the convection in molten samples under given test parameters. In this research, the convection induced in the molten Fe₅₀Co₅₀ alloy was predicted numerically. The magnetohydrodynamic model for the ground-based electromagnetic levitator developed in the previous research was extended to the space application. The same modeling strategies were applied to the electromagnetic levitator in space. Using the numerical model, the convection under various test conditions was predicted: The flow pattern was characterized as a function of the heating current. The maximum convection velocity at various temperatures was estimated with the increasing heating current. Finally, the range of accessible convection velocity was predicted as a function of the critical undercooling of the sample, the minimum positioner control voltage, and the undercooling of the sample. The results are expected to provide critical information for the design of the space experiments and the interpretation of the results.