Study on striking force characteristics of hydraulic jet self-drilling multi-hole nozzle

In order to explore the characteristics of the jet rotation striking force of the self-drilling nozzle, the structural parameters of the nozzle were determined, and a water jet rotation striking force test system was established. The striking force test was carried out under different parameters, including nozzle diameters, jet angles, rotation speeds, jet target distances and jet pressures.The variation rule of the striking force with the influencing factors was analyzed.The results show that the striking force increases with the increase of nozzle diameter, but decreases with the increase of jet angle.Under different jet pressures, there is an optimal rotation speed of 200 r/min to maximize the jet striking force.Near the 6 mm target distance, the jet is fully developed, and the jet strike force is the highest in this interval. The striking force is positively correlated with the increase of jet pressure.When the pressure exceeds 30 MPa, the growth trend of striking force is obviously reduced. Finally, the combined parameters of the maximum jet striking force are discussed.This study provides a reference for the optimization of the working parameters of water jet self-drilling rock breaking.