Experimental investigation of droplet breakup of oxide-forming liquid metals

This work investigates the breakup of liquid metal droplets experimentally using a shock tube. Droplets of Field's metal melt are produced and their flow-induced deformation and rupture are captured by a high-speed camera. Results are compared to previous data on Galinstan droplet breakup using image sequences and deformation data. Regarding differences, we find that Field's metal droplets show slightly larger deformations and breakup into a larger number of smaller fragments, especially at low Weber numbers. We expect this to be an effect of different oxidation rates. However, both oxidizing metals show a very similar behavior with respect to the breakup morphology, transition between modes, and the timing of the deformation across the investigated Weber number range of 10-100. In addition, core features that distinguish the breakup of metals from that of conventional, water-like liquids are confirmed. Based on the similarities, we propose that the findings can be generalized to also represent other oxide-forming metals. Weber number-dependent fits are presented for the initial deformation time, the time of the onset of breakup, and the maximum cross-stream diameter. In addition, we provide an empirical fit for the time-dependent cross-stream deformation and evaluate it against experimental data and models from the literature. The fits can be used directly in numerical studies or help improve current breakup models. Published under an exclusive license by AIP Publishing.https://doi.org/10.1063/5.0064178.