Study On The Strike Characteristics Of Jet Low-pressure High-flow Self-excited Pulse Cavitation

Compared with other water jet technology, low-pressure self-excited pulsed cavitation jet as a new type of high efficient jet technology, it has unique advantages, especially in large storage tank cleaning operation. In this paper, the operation characteristics, the present research situation and application prospect of self-excited pulsed cavitation jet are introduced, and we also summarizes the problems existing in the present study. We perform the theoretical study, experiment and numerical simulation in order to find the influence of operational parameters and structure parameters on target distance, kinetic energy of outlet and the jet frequency.First of all, according to the analysis of low-pressure high flow rate self-excited pulsed cavitation jet flow characteristics, we select and introduces the control equation of turbulent kinetic, the equations of turbulence model, the equations of multiphase flow model and the equations of cavitation model.According to different operation and structure parameters of low-pressure high flow rate self-excited pulsed cavitation jet nozzle internal flow field, we use software FLUENT perform a series of numerical simulation. By analyzing the pressure contours inside the nozzle chamber, we research the distribution changes of low pressure area and cavitation bubbles with time. Comparing the volume fraction of water-vapor and outlet velocity of simulation results, the influence of operation and structure parameters on the distribution of cavitation bubbles and strike characteristics.We perform numerical simulation on low-pressure high flow rate self-excited pulsed cavitation jet external flow field, in order to analyze the change of jet structure and the influence of standoff distance on strike force. Under the condition of gravity and without gravity, we perform numerical simulation on external flow field, analyzed the influence of gravity on strike characteristics. Change the inlet pressure and structure parameters, we research the influence of it on the strike force distribution.In this paper, test purpose, test device and system are introduced. We perform many experiments based on a set of nozzle structural parameters which can produce pulse effect obviously. The optimal standoff distance and pulse jet mechanism of nozzle are analyzed. The influence of structure parameters on the optimal distance and jet frequency are summarized.