Theoretical and numerical studies on the collapse of single‐ and double‐bubble system in water

Abstract

AbstractThe cavitation bubbles that collapse in the hydraulic machinery can cause damage to the structure and the internal wall. In order to find feasible preventive measures, the mechanism of cavitation bubble collapse needs to be thoroughly studied. However, the influence of the initial radius or the interaction between multi‐bubbles has not been studied in depth. In this paper, the collapse process of single‐ and double‐bubble system is studied by the volume of fluid (VOF) method. Three conditions are considered in this paper, single‐bubble (R0 = 0.3 mm, R0 = 0.4 mm) and double‐bubble system (R0,1 = 0.3 mm and R0,2 = 0.4 mm). The time evolution of pressure, bubble radius, radial velocity, and acceleration during the bubble collapse can be obtained. The bubble collapse time, pressure distribution, and radial velocity of single bubble are verified by theoretical values. It is found that with the increase of bubble initial radius, the collapse, and rebound time is delayed, the maximum pressure of the bubble center increases, the minimum radius of the bubble decreases, the maximum radial velocity increases. In double‐bubble system, during the first rebound of the small bubble, the central pressure, radius and radial velocity of the small bubble fluctuate with time. And the collapse time of each bubble is delayed, the maximum central pressure decreases and the minimum radius of the bubble increases.