Mapping of cavitation intensity in a novel dual-frequency ultrasonic reactor of capacity 10 L

Abstract

Mapping of a dual-frequency ultrasonic reactor was performed based on measurements of local cavitation intensity at various horizontal and vertical planes in the reactor for single frequency operation (22 kHz or 44 kHz) and dual-frequency operation (22 + 44 kHz) at varying input power of 250 and 450 W. The average cavitation intensity ranged between 73.6 and 86.7 W/cm2, 38.75 and 64.4 W/cm2, 86.7 and 100.6 W/cm2 for the operating frequencies of 22, 44 and 22 + 44 kHz respectively at maximum input power of 450 W depending on the location. Bubble dynamics simulations at various frequencies were also performed using the Keller-Miksis equation and the trends of bubble radius, collapse temperature and pressure were found to effectively match the experimental findings for cavitation intensity. The work has clearly elucidated the dependency of the cavitational activity on location, power dissipation and operating frequency mode with dual-frequency operating showing higher cavitation intensity.