Breakage of a single oil drop in water via acoustic and hydrodynamic cavitation

Liquid-liquid emulsions find extensive applications across several industrial sectors, including healthcare, personal care, home care, food, and agrochemicals. Acoustic cavitation (AC) and hydrodynamic cavitation (HC) have emerged as viable options for producing such emulsions. Therefore, understanding the droplet-cavity interaction leading to droplet breakup is crucial. Experiments were conducted to understand the interactions between the cavity/cavity cloud and oil droplet. AC was generated using an ultrasonic horn, whereas a snapping mechanism was used for generating HC. The droplet size distribution (DSD) via these two methods was analyzed. Using image processing and autocorrelation analysis, a decay rate ( b ) was obtained for both cavitation methods. The b is larger, and D90 is smaller for HC than AC. Both cavitation methods resulted in a bimodel droplet distribution. Smaller droplets are created upon interaction with the collapsing cavity, whereas large droplets are due to cavitation-induced turbulent shear. The study improves understanding of the interactions of oil drops suspended in water with cavities generated by AC and HC scenarios. The experimental data also provides a useful basis for developing and validating improved models for simulating cavitation-induced droplet breakage, enabling enhanced applications of cavitation for emulsification in the chemical industries.