Abstract
This study introduces results of experiments concerning the effects of sonotrode tip shape on cavitation intensity and acoustic streaming in a water bath irradiated with high-intensity ultrasound.Sonotorode with plane, trapezium and cone tips, were used to conduct three kinds of experiments : 1 - PIV investigation of acoustic streaming underneath the sonotrode tip, 2 - measurements of cavitation efficiency using the Weissler reaction, 3 - measurements of perfect mixing time of a sonificated water bath. The sonotrode tip diameter was 48 mm, the vibration amplitude varied from 10 to 70 micro m (p-p).
The results revealed that the acoustic streaming pattern is depended on the tip shape, being varied from a jet-like downward streaming for the plane tip to a distributed and relatively slow cone tip. Although the acoustic streaming velocity was varied with distance from the tip, the averaged values for cone tip was more than twice less than that for the plane tip at a constant vibration amplitude. These data were also confirmed by the perfect mixing time measurements. In contrary, cavitation efficiency was twice better for the cone tip as compared to the for the plane tip. Thus, the results indicate that controlling the flow pattern of acoustic streaming by changing the sonotrode tip shape is able to improve cavitation efficiency and lead to a better treatment performance in ultrasonic-assisted processes.
