| Self-resonating Cavitation(SRC) water jet is possessed of the advantage of cavtitation and pulsed water jet, which usually has been used in the field of coal mining, oil drilling and also has been preliminarily used in cleaning ship hull and pipes etc. It features with high efficiency, water-saving, time-saving and low cost etc. Studying on SRC water jet that is used in cleaning will promote the development of cleaning field and benefit economics and society widely.This dissertation is aimed at designing optimum structural parameters of SRC jet nozzle, which is based on the theories of bubble dynamics, cavitation, hydrodynamics and turbulence etc. The mechanism of cleaning by cavitation water jet has been studied, and which have been analyzed includes the characteristics of cleaning by cavitation water jet, the formation and mechanism of cavtitation and pulsed water jet, the influencing factors and intrinsic-external conditions of cavitation incipient. Based on the theories of fluid transients, hydroacoustics, fluid resonance and impedence method, the mechanism of SRC water jet and organ-pipe SRC jet nozzle, they have been analyzed theoretically, such as the characteristics of organ-pipe resonator in creating power SRC water jet, the flow characteristic equation of the nozzle and the calculation formulas determining the length of an resonator. The physical model of organ-pipe resonator has been built that based on concatenated diferent diameter homogeneous pipes. It has been given that the numerical solution model of the natural frequency of an organ-pipe resonator that includes seven unknown variables and seven equations. The formulas determining the natural frequency of an organ-pipe resonator have been derived.Based on the theory and simulation study, the characteristic experiment of SRC water jet is carried out that includes the measurement of the vibration of nozzle and target, the measurement of water jet impact force to target and various cleaning efect experiment. The parameters, such as nozzle diameter, resonator length of the organ-pipe SRC jet nozzle, affect the occuring of SRC water jet and the effect of cleaning have been obtained. The cleaning ability of the system have been improved greatly by using SRC jet nozzle, so that it is specially useful for the cleaning engineering vehicles. Finally, based on the principles of the combination of theory, simulation and experiments and the principle of frequency matched, the design model of SRC jet nozzle is given in this dissertation. |
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