Non-contact droplet breakup induced by acoustic potential wells

Acoustic potential wells provide a promising non-contact method for precise droplet manipulation; however, the underlying mechanisms of droplet breakup in high-intensity acoustic fields remain insufficiently understood. This study explores the relationship between droplet breakup and the pressure/velocity fields through theoretical analysis of the forces acting on droplets. A numerical model is used to elucidate the generation mechanism of sub-droplets, while the influence of liquid viscosity and surface tension on non-contact atomization is systematically examined. Experimental validation is conducted using high-speed imaging to capture droplet breakup dynamics and laser particle size analysis to quantify the atomized droplet distribution. Simulation results reveal that droplet breakup in acoustic potential wells arises from the synergistic interaction between periodic acoustic radiation forces and Bernoulli forces induced by the velocity field. Additionally, under identical energy inputs, liquid viscosity exerts a more significant influence than surface tension in determining atomized droplet size. These findings advance the fundamental understanding of non-contact atomization and provide valuable insights for the simulation and optimization of ultra-fine atomization processes.