Realization of cavitation fields based on the acoustic resonance modes in an immersion-type sonochemical reactor

Different modes of cavitation zones in an immersion-type sonochemical reactor have been realized based on the concept of acoustic resonance fields. The reactor contains three main components, namely a Langevin-type piezoelectric transducer (20 kHz), a metal horn, and a circular cylindrical sonicated cell filled with tap water. In order to diminish the generation of cavitation bubbles near the horn-tip, an enlarged cone-shaped horn is designed to reduce the ultrasonic intensity at the irradiating surface and to get better distribution of energy in the sonicated cell. It is demonstrated both numerically and experimentally that the cell geometry and the horn position have prominent effects on the pressure distribution of the ultrasound in the cell. With appropriate choices of these parameters, the whole reactor works at a resonant state. Several acoustic resonance modes observed in the simulation are realized experimentally to generate a large volume of cavitation zones using a very low ultrasonic power.