Study on the Dynamic Characteristics of the Impact Loads in a Near-Wall Double-Cavitation Bubble Collapse

Abstract

Cavitation and cavitation erosion are complex hydrodynamic behaviors that significantly influence the stability and reliability of pumping units in aerospace and navigation power systems, hydraulic engineering, and other fields. Studies on cavitation have primarily and heavily focused on the collapse of multiple cavitation bubbles; understanding the movement of multiple cavitation bubbles is important for cavitation research. In this study, the collapse process of near-wall double-cavitation bubbles was numerically simulated and experimentally verified, and the evolution of the near-wall double-cavitation bubble collapse was investigated. Two different distances were altered in the study. The distance between the double-cavitation bubble and the distance between the cavitation bubbles and the wall, the effects of dimensionless parameters, such as the near-wall coefficient and the cavitation bubble spacing coefficient, the collapse time, jet angle, and impact load on the wall can be determined. It was found that the collapse time of the double-cavitation bubbles decreased in a negative exponential distribution with an increase in the cavitation bubble spacing coefficient, along with decreases in a negative exponential distribution with an increase in the near-wall coefficient. The jet angle increased in a negative exponential distribution with an increase in the cavitation bubble spacing coefficient and decreased in a negative exponential distribution with an increase in the near-wall coefficient. The impact load on the wall initially increased and then decreased in the form of a quadratic function, with an increase observed in the cavitation bubble spacing coefficient. With an increase in the near-wall coefficient, the impact load on the wall first decreased, then increased, and finally decreased in the form of a cubic function.