Droplet formation at megahertz frequency

• Published in: AIChE journal Vol. 63; no. 6; pp. 2367 - 2377
• Main Authors: Miers, John C., Zhou, Wenchao
• Format: Journal Article
• Language: English
• Published: New York American Institute of Chemical Engineers 01.06.2017
• Subjects: Deposition; Droplets; Flux density; Industrial applications; Inkjet printing; Mathematical models; Nozzles; Numerical models; Reagents; Spray cooling
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.15578

Droplet formation has been a fascinating subject to scientists for centuries due to its natural beauty and importance to both scientific and industrial applications, such as inkjet printing, reagent deposition, and spray cooling. However, the droplet generation frequency of common drop‐on‐demand (DOD) jetting techniques is mostly limited to ∼10 kHz. This article presents an investigation of the possibility of jetting at megahertz frequencies to boost the productivity of DOD material deposition by ∼100 times. The focus of this article is to understand the limitations of generating droplets at a megahertz frequency and to explore possible solutions for overcoming these limitations. A numerical model is first developed for the simulation of droplet formation dynamics. The numerical model is validated against available experimental data from the literature. Aided by insights gained from scaling analysis, the validated model is then used to study the effects of different parameters on high frequency jetting. The study finds energy density input to the nozzle is the key to achieve megahertz frequency droplet breakup. © 2016 American Institute of Chemical Engineers AIChE J , 63: 2367–2377, 2017