LAUSR

Cavitation greatly affects the safe and stable operation of hydraulic machineries and thus has been key challenge in this field. Cavity collapse caused by cavitation can form transient characteristics such as high temperature, high pressure, strong shock wave, and high-speed micro-jet, which may cause serious damage to nearby solids. Cavitation can be affected by many intercoupled factors during the collapse transition. However, existing research rarely focuses on the analysis of its influencing factors. This research aims to reveal the collapse mechanism of cavitation, the parameters of each factor, and the influencing rules of the cavity collapse process. Molecular dynamics method was employed to analyze the evolution process of cavity collapse in the computational domain of liquid argon under different conditions. The influences of relaxation time, system temperature, and cavity size on cavity collapse were investigated. These simulation results showed that when the relaxation time was within 1 ns, the longer the relaxation time, the more likely the system molecules formed a stable state, and the more easily the cavities collapsed. When the relaxation time was greater than 0.2 ns, the difference in the process of collapse was smaller. When the temperature of the system was within 80 K, as the temperature increased, the thermal motion of the molecules intensified to increase the kinetic energy and weaken the intermolecular gravitation, shortening the time for cavities to reach the collapse point. When the temperature reached 80 K, as the temperature continued to increase, the time of collapse point and the process basically unchanged. When the initial cavity size was within 15 Å, the larger the initial cavity size, the less likely the cavities tended to collapse. When the cavity size was larger than 15 Å, the cavities were further less likely to collapse as the cavity size increased. The research results can provide theoretical support for the study of cavitation characteristics.