| In this thesis,aiming at the problems of short target distance and small nozzle diameter in the process of rock breaking by ordinary jet,a method of rock breaking by high-pressure energy-gathering water jet is proposed.In this thesis,combined with mechanical structure design,theoretical analysis,numerical simulation and experimental research,the design of high-pressure energy-gathering water jet generating device and rock breaking performance research are carried out.The purpose of this thesis is to develop a high-pressure energy-gathering water jet generating device and the failure mechanism of rock under the action of high-pressure energy-gathering water jet,to explore the influence of high-pressure energy-gathering water jet operating parameters on rock breaking performance,and to provide a scientific basis for improving the rock breaking efficiency of high-pressure energy-gathering water jet.Combined with the existing pulse water jet generating device,a high-pressure energy-gathering water jet rock breaking technology is proposed and its rock breaking device is designed.Based on the theory of fluid mechanics and dynamics,the dynamic model of the high-pressure energy-gathering water jet generating device is established and the dynamic characteristics of the device are studied.The influence of the structural parameters of the device and the system pressure on the performance of the device is analyzed.Combined with theory and simulation,the design and strength check of the pressurization system,the design and performance analysis of the buffer system and the design of the sealing system are carried out,which provides a theoretical basis for the design of the structure of the high-pressure energy-gathering water jet rock breaking device.Based on the theory of fluid mechanics,the physical model of high-pressure energy-gathering water jet nozzle is established to explore the energy gathering mechanism of nozzle.In order to explore the formation process and microscopic mechanism of high-pressure energy-gathering water jet,numerical models of nozzles with different inner contour shapes and different structural parameters are established.The influence of nozzle inner contour shape and structural parameters on nozzle performance is analyzed.The influence of nozzle structural parameters on nozzle performance and the optimal nozzle structural parameters are obtained by orthogonal test method,which provides technical guidance for the design of high-pressure energy-gathering water jet nozzle.In order to reveal the failure mechanism of rock under the superposition and coupling of multiple high-pressure energy-gathering water jet,the SPH-FEM algorithm is used to establish the dynamic model of ’ spherical ’ high-pressure energy-gathering water jet impact rock breaking,and to reveal the rock under the impact of high-pressure energy-gathering water jet.The crushing process and the internal stress variation of the rock,including the failure mechanism of the rock unit in the crushing zone and the crack propagation zone,analyze the rock expansion mechanism and the macroscopic morphology of the crushing;the influence of jet velocity,jet diameter and surrounding rock stress on the rock breaking performance of high-pressure energy-gathering water jet is studied,which provides theoretical guidance for the study of rock breaking performance of high-pressure energy-gathering water jet.In order to explore the time-dependent characteristics of high-pressure energy-gathering water jet impact rock breaking and the influence of impact target distance and impact frequency on its rock breaking performance,a high-pressure energy-gathering water jet impact rock breaking test bench was built and a high-pressure energy-gathering water jet impact rock breaking performance test study was carried out.The time-dependent characteristics of rock breaking morphology,rock breaking volume,crushing pit diameter and depth under the impact of high-pressure energy-gathering water jet were mastered.The optimal impact target distance of high-pressure energy-gathering water jet impact rock was pointed out.The frequency characteristics of high-pressure energy-gathering water jet impact rock breaking were explored,which provided technical guidance for the study of high-pressure energy-gathering water jet rock breaking performance.The dissertation has 76 figures,17 tables and 102 references. |
PDF Full Text Request