Study On The Cavity Bubble Motion Characteristics Of Low-Pressure Self-Excited Pulse Cavitation Jet

Self-excited pulsed cavitation jet is a new type of high efficient jet technology. It enriches the development of manufacturing, washing and digging industry working methods. For cleaning large storage equipment, the low-pressure large flow self-excited pulsed cavitation water jet highlights its unique advantage and brings significant influence to washing industry. So, for promoting the practical application, it is necessary to further study the low-pressure self-excited pulsed cavitation water jet technology.Based on the domestic and foreign literature, the research background, research significance and application prospect of the low-pressure self-excited pulsed cavitation water jet is summarized and the present problems are analyzed.The bubble movement characteristics, the mass transfer characteristics and the jet frequency characteristics of low-pressure self-excited pulsed cavitation water jet are analyzed. The impact of the air content, air distribution, pressure distribution of flow field, the surface property of the target, flow field temperature, viscous stress on the cavitation are summarized. Combining the theory of "spring" and self-excited pulsed jet frequency characteristic, this paper explained the generating mechanism low-pressure self-excited pulsed cavitation jet.The multiphase model, cavitation model and turbulent model are summarized, and the suitable one is used in the numerical simulation. The grid independence and the influence of time step are analyzed, and the appropriate one will be chosen for the numerical simulation. Considering the influence of gravity, the low-pressure self-excited pulsed cavitation water jet is simulated and analyzed. The result shows the gravity can affect the inner flow field.The low-pressure self-excited pulsed cavitation water jet nozzle is designed to be transparent, and the self-designed test apparatus has been set up. Through the test, the phenomena of the flow field inner the nozzle is described and analyzed. The impact of working pressure, up nozzle diameter, chamber length and collision angle on the frequency and amplitude of self-excited pulse is analyzed. The waveform and frequency domain feature of low-pressure self-excited pulse cavitation jet is analyzed.