The Dynamic Study On The Series Pulsed Jet Nozzle

The self-excited oscillation pulsed jet nozzles was used widely in the drilling and crashing in the oil industry, for this, a new series pulsed jet device is designed according to hydro-acoustics and fluid dynamics in order to enhance the pulsed effects and impulse force of the self-excited oscillation pulsed nozzle. Then a new way was proposed for designing a generant equipments of the high-pressured pulsed water jets.This paper introduced the structure of the pulsed jet device, which is composed by the oscillation organ–pipe and Helmholtz oscillation cavity. The mechanism of the self-excited oscillation pulsed jet and the effective feedback conditions were analyzed in detail. The transfer matrix and impedance methods were used for investigating the inherent frequencies of the pulsed jet device and frequency characteristic of water jet, however a model which described the jet in the oscillation cavity was proposed.The rationality of the theoretical analyses of the series pulsed jet device was tested and verified by experimental, and the effects of the structure of the downstream impacting walls on the self-excited oscillation pulsed jet was discussed in this paper, the study also focused on the variations of pressure pulses and pulsed jet frequency with the structural parameters of the series oscillations cavities, the erosion effectiveness between the oscillation organ–pipe and Helmholtz oscillation cavity is compared. The experiment results can be summarized as follows: The impulsive effectiveness and the impulse force of the jet can be greatly enhanced in the case of the structure going well. Considering the same conditions, the peak value of the jet for the case of series oscillation cavity is larger about 20% than that of Helmholtz oscillation cavity. In addition, the impulsive effectiveness goes up to be optimal in the case of a suitable pump pressure.The experiment results have been conducted to verify the theories according to the experiment study on the self-excited oscillation pulsed jet device, the optimization configuration parameter also can be obtained. The experiment results indicate that the impulse force in the case of series oscillation cavity is much larger than that of one cavity and the research is successful.