Quantitative characterization and influencing factors analysis of dual-frequency ultrasonic cavitation intensity based on fluorescence analysis

Ultrasonic cavitation assisted processing technology has been widely used in machinery, chemistry, biology, food, and other fields. Compared with single-frequency ultrasonic cavitation, dual-frequency ultrasonic shows unique advantages such as cavitation bubbles imploding more strongly, breaking cavitation shielding, and reducing cavitation threshold. It has higher ultrasonic cavitation intensity and has received more extensive attention. However, the quantification of cavitation intensity enhanced by dual-frequency ultrasonic is a complex problem. This paper quantitatively characterized the cavitation intensity using fluorescence analysis method. The results showed that the samples fluorescence indexes after ultrasonic cavitation increased to 1.68–10.60 times. The dual-frequency ultrasonic could significantly enhance the cavitation intensity. The smaller frequency differences and lower-frequency combination (20+30 kHz) led to the maximum fluorescence index differences of 117.6 and 6677.3. The effect of dual-frequency ultrasonic on cavitation intensity was further enhanced accompanied by the increase of ultrasonic power, and the extension of irradiation time leaded to a higher fluorescence index, which was due to the accumulation of ·OH. The ultrasonic mode had the most significant impact on cavitation intensity. This study analyzed the cavitation intensity enhanced by dual-frequency ultrasonic quantitatively, which provided a basis for further research and utilization of dual-frequency ultrasonic cavitation.