Abstract
This work experimentally and analytically investigated the incipient cavitation behavior in four liquids with different physical properties: ethanol, de-ionized water, glycerine, and aluminum melt under ultrasonic irradiation close to the cavitation threshold with a frequency of 20 kHz. To identify the cavitation structure development and bubble motion of different liquids, cavitation structure under condition close to the cavitation threshold was in-situ observed via high-speed photography for optically transparent liquids and synchrotron radiation X-ray radiography technology for aluminum melt. The dynamic process of the cavitation bubble was numerically simulated on the bubble wall motion. Bubble characteristics were analyzed by more accurate relevant dimensionless quantities comparison obtained from the translational maximum bubble velocity measured by Particle Image Velocimetry (PIV). Based on the simulation results through multi-technology combination methods and dynamic simulation, the incipient cavitation characteristics of various liquid bulks in experimental conditions were estimated and compared. The insights gained from this study are valuable for improving the design and optimization of industrial processes involving cavitation, such as ultrasonic degassing, ultrasonic-assisted metal casting, and material processing. Understanding these cavitation characteristics can lead to more efficient and controlled applications in these fields and help in identifying more suitable transparent media for simulating the cavitation behavior of metal melts.