The Formation Principle and Characteristics of Self-supercharging Pulsed Water Jet

Abstract

High-pressure pulsed water jet technology has high development potential in the field of rock fragmentation. Technical bottlenecks such as difficulty in pressurization and inconvenient frequency adjustment for existing types of pulsed jets, a self-supercharging pulsed water jet generation method is proposed based on the theory of pulsed water jet and principle of hydraulic boosting, which changes the flow direction of fluid medium through the valve core to make the piston reciprocate in the cylinder, and relies on the effective area difference between the front and rear chambers in the stroke stage of the piston to realize the organic combination of “pulse” and “supercharging” of the jet, so as to self-supercharging pulsed water jet. Based on revealing the formation principle of self-supercharging pulsed jet, the self-supercharging pulsed jet generation system was designed, and the self-supercharging pulsed jet testing platform was built, many groups of pressure collection and jet shape observation experiments were carried out for different operating parameters. The research results show that both the jet pressure and the jet shape show periodic change, and higher pulse pressure can be obtained at lower inlet pressure. The error of the pressure ratio calculated according to the experimental results is less than 3% compared with the theoretical design value, thus verifying the feasibility of the method . Pulse pressure and pulse frequency are controllable, that is, as the inlet flow rate increases in the stroke phase of the piston, the pulse pressure and pulse frequency increase, and the pulse duration decreases, as the inlet flow rate increase in the backward stroke phase of the piston, the pulse frequency increases, and the pulse pressure and pulse duration remain unchanged. The research results lay the foundation for enriching the theory of pulsed jet generation and expanding its application range.