Kelvin-Helmholtz instability as one of the key features for fast and efficient emulsification by hydrodynamic cavitation

Boček, Žan (author), Petkovšek, Martin (author), Clark, Samuel J. (author), Fezzaa, Kamel (author), Dular, Matevž (author)

The paper investigates the oil–water emulsification process inside a micro-venturi channel. More specifically, the possible influence of Kelvin-Helmholtz instability on the emulsification process. High-speed visualizations were conducted inside a square venturi constriction with throat dimensions of 450 µm by 450 µm, both under visible light and X-Rays. We show that cavity shedding caused by the instability results in the formation of several cavity vortices. Their rotation causes the deformation of the oil stream into a distinct wave-like shape, combined with fragmentation into larger drops due to cavitation bubble collapse. Later on, the cavity collapse further disperses the larger drops into a finer emulsion. Thus, it turns out that the Kelvin-Helmholtz instability is similarly characteristic for hydrodynamic cavitation emulsification inside a microchannel as is the Rayleigh-Taylor instability for acoustically driven emulsion formation.

• Language: English
• Keywords: emulsion, hydrodynamic cavitation, Kelvin-Helmholtz instability, Venturi microchannels
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2024
• Number of pages: 9 str.
• Numbering: Vol. 108, art. 106970
• PID: 20.500.12556/RUL-159634
• UDC: 532.528
• ISSN on article: 1350-4177
• DOI: 10.1016/j.ultsonch.2024.106970
• COBISS.SI-ID: 201951491
• Publication date in RUL: 16.07.2024

Record is a part of a journal

• Title: Ultrasonics Sonochemistry
• Shortened title: Ultrason. sonochem.
• Publisher: Butterworth-Heinemann, Elsevier Science
• ISSN: 1350-4177
• COBISS.SI-ID: 707668

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: emulzija, hidrodinamska kavitacija, Kelvin-Helmholtzova nestabilnost, Venturijevi mikrokanali