Gas Jet – Soap Film Interactions for Understanding Nanodroplet Atomization

Abstract

Surfactant films have been a popular area of study, but research has been limited into their behavior under impact from a gas jet. Since it was recently discovered that nanodroplets can be efficiently atomized from jet-induced disintegration of thin liquid films, this thesis takes a broad view to better understand the phenomena governing this jet – film interaction. A 1.25 m flowing soap film setup was constructed and optimized. The thickness of the film was studied at multiple positions under a variety of flow rates and surfactant concentrations. It was observed that thickness increased linearly with flow rate and decreased with surfactant concentration. Additionally, the thickness increased with distance from the injection point at low flow rates, but at high flow rates, the trend was reversed. During jetting studies, a horizontal gas jet impacted the vertical soap film, and the interactions were recorded with high-speed video and categorized into different responses. These results indicated the existence of a critical pressure during jetting that separated a cavity phase from a bubbling phase; this pressure was determined to be independent of film thickness. The collective findings from this thesis will inform future studies of the mechanisms of jet rupture, furthering the development of the atomization technology serving as a reduced-energy precursor for nanoparticle production.