Droplet Ejection at Controlled Angles via Acoustofluidic Jetting.
Phys Rev Lett
; 125(18): 184504, 2020 Oct 30.
Article
em En
| MEDLINE
| ID: mdl-33196229
ABSTRACT
We study the nozzle-free ejection of liquid droplets at controlled angles from a sessile drop actuated from two, mutually opposed directions by focused surface acoustic waves with dissimilar parameters. Previous researchers assumed that jets formed in this way are limited by the Rayleigh angle. However, when we carefully account for surface tension in addition to the driving force, acoustic streaming, we find a quantitative model that reduces to the Rayleigh angle only when inertia is dominant, and suggests larger ejection angles are possible in many practical situations. We confirm this in demonstrating ejection at more than double the Rayleigh angle. Our model explains the effects of both fluid and input parameters on experiments with a range of liquids. We extract, from this model, a dimensionless number that serves as an analog for the typical Weber number for predicting single droplet events.
Texto completo:
1
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article