Ultrasonic Atomization Of Metallic Melts : Modeling And Case Studies

摘要

The mechanism of ultrasonic atomization of liquids is modeled. The goal is to explain why practical atomizers do not operate in accordance with previous analytical works. Droplet diameter is calculated using Kelvin's capillary-wave hypothesis, which assumes that disintegration is the result of unstable liquid surface oscillations. The droplet size distribution, generally supposed to be narrow and near-monodisperse, is also predicted. Calculations show that the liquid surface oscillation wavelength slightly differs from Kelvin's expression, and that the predicted distribution is effectively narrow, but not exactly log-normal. This model describes therefore quite well practical ultrasonic atomizers. Theoretical droplet size volume distributions are compared to experimental ones for water, molten zinc and molten magnesium. Metallic melts are atomized at 20 kHz in a vessel developed at HEVs.