A Velocity Coupling Method for Atomization Modeling: Application to Piezoelectric Pulsation-Driven Glass Nozzles

A velocity coupling method is presented for numerical investigation of droplet formation through glass nozzles driven by piezoelectric pulsation. The key idea is to first model the phenomena inside and outside of the nozzle separately. This approach allows in-nozzle and out-nozzle models to focus on their respective modeling challenges, e.g., coupled multiphysics beyond fluid mechanics for the former and liquid–air interface tracking for the latter. After coupling them through velocity mapping, the complete atomization process can be simulated. The results show that periodic pulsation of the piezoceramic component attached to the glass capillary drives regular displacement of the capillary wall, leading to a rhythmic change in the chamber volume and hence the flow rate ejected from the nozzle. Such disturbance results in the breakup of a liquid jet into a stream of droplets. To demonstrate model effectiveness, the impact of disturbance frequency on atomization has been analyzed.