Calculation And Analysis Of Single-bubble And Double-bubble Ultrasonic Cavitation Noise Characteristic

Ultrasonic cavitation noise is noise generated during the periods of the ultrasoniccavitation bubble formation, development and collapse. Different values can be measured atdifferent periods of cavitation noise, from which the characteristics and development ofultrasonic cavitation can be inferred. At the same interval of development, on the other hand,the values of cavitation noise of single-bubble and double-bubble are also dissimilar. Thus,the analysis of single-bubble and double-bubble ultrasonic cavitation noise characteristics canprovide basic theory for the noise reduction of ultrasonic cavitation applications, such asultrasonic cleaning.Based on R-P model, MATLAB is used to analyze the effects of bubble linearity, soundfrequency, and sound pressure amplitude on single-bubble’s ultrasonic cavitation. Thecalculational results show that the pressure amplitude and frequency contribute differently.Increasing the amplitude will deepen collapse, but the collapse time has been delayed.However, increasing frequency will facilitate the process of cavitation. Increasing frequencycan make the bubbles collapse in a larger radius and the collapse of time will be advanced.The initial radius of cavitation bubble only plays a role of initial value, and it will not promoteor hinder the process of cavitation.Based-on ultrasonic cavitation dynamic differential equation of single-bubble anddouble-bubble, acoustic radiation in the fluid is formulated by Lighthill equation. MATLABis employed to analyze the effects of bubble linearity, double-bubble distance, soundfrequency, sound pressure amplitude and bifrequency ultrasound on cavitation noise. Theexperimental result shows that under the same beginning conditions, the cavitation noisecurves of single-bubble and double-bubble have different characteristics: the peak ofdouble-bubble’s cavitation noise is2-3orders of magnitude higher than that ofsingle-bubble’s cavitation noise. Such a peak of cavitation noise results from the collapse ofthe single-bubble and double-bubble.For single-bubble, bubble’s linearity, frequency of sound, pressure amplitude of soundand bifrequency ultrasound all reveal crucial impacts on cavitation noise. The dominant factorto determine the characteristics of cavitation is bubble’s linearity, followed by pressure amplitude of sound, then frequency and bifrequency ultrasound. Cavitation noise reachesmaximum when the measurements of the pressure amplitude in two components of thebifrequency ultrasound are equal. For double-bubble, unlike single-bubble, the critical factorsof cavitation noise are only two bubbles’ linearity and pressure amplitude of sound, whiledistance between double-bubble has little effects, and the effects of frequency of sound andbifrequency ultrasound can almost be ignored.