Experimental study on multi-pulse characteristics of pressurized pulsed water jet
The water hammer effect generated by the jet tip contributes to the efficient crushing of hard rock.In order to further clarify the initial pulse(jet tip)characteristics of pressurized pulsed waterjet,a high-speed imaging system was used to conduct information collection ex-periments on the flow field of pressurized pulsed water jet.The halo was used as a marker point to quantitatively characterize the instantaneous velocity and penetration distance of the multi pulse tip of the jet.The results show that the pressurized pulsed water jet nurtures mul-tiple pulse characteristics during the single cycle propagation process,and the multiple pulses become the initial pulse through pursuit approximation and dynamic competition of coverage.The maximum velocity of the initial pulse occurs in the second pulse.At the same time,multi pulse dynamic competition leads to the existence of a"double peak"water hammer optimal tar-get in the jet.As the predetermined erosion target distance increases,the position of the initial pulse peak velocity shifts from the first pulse to the second pulse,which means that the water hammer optimal target shifts from the first target near the nozzle to the second target far from the nozzle.The research results provide a basis and reference for further utilizing the initial pulse of pressurized pulsed water jet.
pressurized pulsed water jetinitial pulsemultiple pulseinstantaneous velocity of pulse tippenetration distance of pulse tipwater hammer optimization target