Experimental modulation and theoretical simulation of zonal oscillation for electrostatically levitated metallic droplets at high temperatures

The second- and third-order zonal oscillations of metallic droplets at high temperatures beyond 2000 K were experimentally achieved by electrostatic levitation. To quantitatively describe the suspension stability of different metallic droplets, a stability factor model was proposed as a function of the surface tension and density. The influences of droplet size and temperature on the oscillation pattern, oscillation frequency, and oscillation amplitude were analyzed. As a supplement to experiment, a feasible mathematical model of droplet deformation and oscillation, coupling the effects of electrostatic and flow fields, was established to study the underlying mechanism of droplet dynamics at high temperatures. The simulation not only reproduced the experimental observations, but also predicted the evolution characteristics of higher-order oscillations. The inherent relationships between the oscillation frequency and the droplet size, density, and surface tension of liquid metals were systematically investigated by simulation. Moreover, the suspension stabilities of nine typical metallic droplets were derived and compared with the simulation results.