Liquid dripping dynamics and levitation stability control of molten Ti-Al-Nb alloy within electromagnetic fields

The dripping dynamics of the electromagnetically levitated (EML) liquid Ti-Al-Nb alloy under high temperatures was investigated by both numerical simulation based on the Arbitrary Lagrangian-Eulerian method and corresponding EML experiments. A dripping formation parameter ϵD was defined to describe the critical shape of alloy droplet. According to the simulated results, the high-temperature dripping phenomenon took place when ϵD < 0.68, which was in good agreement with experimental data. When dripping event occurred, the Lorentz force applied on alloy droplet decreased by approximately 11.7% within 0.07 s. Three typical methods were accordingly proposed to avoid the dripping failure of a bulk liquid Ti-Al-Nb alloy, which was implemented by enhancing electric current, adjusting levitation coil diameter, or increasing coil winding number. To control the droplet shape, the deformation pattern and the flow behavior of the liquid alloy were studied in a wide current range from 700 to 1400 A. With the increase in excitation current, the cone-shaped alloy melt transformed to a rhombus, and the flow behavior transformed from a typical four toroidal flow vortexes up to a complex eight toroidal flow vortexes. Moreover, the centroid position of liquid alloy rose up significantly at first and then slowly approached to levitation ceiling.