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Investigation of hydroxyl-terminated polybutadiene propellant breaking characteristics and mechanism impacted by submerged cavitation water jet 被引量:1
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作者 Wenjun Zhou Meng Zhao +3 位作者 Bo Liu Youzhi Ma Youzhi Zhang Xuanjun Wang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期559-572,共14页
A submerged cavitation water jet(SCWJ)is an effective method to recycle solid propellant from obsolete solid engines by the breaking method.Solid propellant's breaking modes and mechanical process under SCWJ impac... A submerged cavitation water jet(SCWJ)is an effective method to recycle solid propellant from obsolete solid engines by the breaking method.Solid propellant's breaking modes and mechanical process under SCWJ impact are unclear.This study aims to understand those impact breaking mechanisms.The hydroxyl-terminated polybutadiene(HTPB)propellant was chosen as the research material,and a self-designed test system was used to conduct impact tests at four different working pressures.The high-speed camera characterized crack propagation,and the DIC method calculated strain change during the impact process.Besides,micro and macro fracture morphologies were characterized by scanning electron microscope(SEM)and computed tomography(CT)scanning.The results reveal that the compressive strain concentration region locates right below the nozzle,and the shear strain region distributes symmetrically with the jet axis,which increases to 4% at first 16th ms,the compressive strain rises to 2% and 6% in the axial and transverse direction,respectively.The two tensile cracks formed first at the compression strain concentrate region,and there generate many shear cracks around the tensile cracks,and those shear cracks that develop and aggregate cause the cracks to become wider and cut through the tensile cracks,forming the tensile-shear cracks and the impact parts eventually fail.The HTPB propellant forms a breaking hole shaped conical after impact 10 s.The mass loss increases by 17 times at maximum,with the working pressure increasing by three times.Meanwhile,the damage value of the breaking hole remaining on the surface increases by 7.8 times while 2.9 times in the depth of the breaking hole.The breaking efficiency is closely affected by working pressures.The failure modes of HTPB impacted by SCWJ are classified as tensile crack-dominated and tensile-shear crack-dominated damage mechanisms. 展开更多
关键词 Submerged cavitation water jet Hydroxyl-terminated polybutadiene propellant Breaking characteristics Failure modes
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The Optimization Design of the Nozzle Section for theWater Jet Propulsion System Applied in Jet Skis
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作者 Cheng-Yeh Li Jui-Hsiang Kao 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第3期2277-2304,共28页
The performance of a water jet propulsion system is related to the inlet duct,rotor,stator,and nozzle.Generally,the flow inlet design must fit the bottom line of the hull,and the design of the inlet duct is often limi... The performance of a water jet propulsion system is related to the inlet duct,rotor,stator,and nozzle.Generally,the flow inlet design must fit the bottom line of the hull,and the design of the inlet duct is often limited by stern space.The entire section,from the rotor to the nozzle through the stator,must be designed based on system integration in that the individual performance of these three components will influence each other.Particularly,the section from the rotor to the nozzle significantly impacts the performance of a water jet propulsion system.This study focused on nozzle design and established referable analysis results to facilitate subsequent integrated studies on the design parameters regarding nozzle contour.Most existing studies concentrate on discussions on rotor design and the tip leakage flow of rotors or have replaced the existing complex computational domain with a simple flow field.However,research has yet to implement an integrated,optimal design of the section from the rotor to the nozzle.Given the above,our program conducted preliminary research on this system integration design issue,discussed the optimal nozzle for this section in-depth,and proposed design suggestions based on the findings.This program used an existing model as the design case.This study referred to the actual trial data as the design conditions for the proposed model.Unlike prior references’simple flow field form,this study added a jet ski geometry and free surface to the computational domain.After the linear hull shape was considered,the inflow in the inlet duct would be closer to the actual condition.Based on the numerical calculation result,this study recommends that the optimal nozzle outlet area should be 37%of the inlet area and that the nozzle contour should be linear.Furthermore,for the pump head,static pressure had a more significant impact than dynamic pressure. 展开更多
关键词 water jet propulsion system ROTOR nozzle outlet area nozzle contour
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Stress release mechanism of deep bottom hole rock by ultra-high-pressure water jet slotting 被引量:1
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作者 Hua-jian Wang Hua-Lin Liao +6 位作者 Jun Wei Jian-Sheng Liu Wen-Long Niu Yong-Wang Liu Zhi-Chuan Guan Hedi Sllami John-Paul Latham 《Petroleum Science》 SCIE EI CAS CSCD 2023年第3期1828-1842,共15页
To solve the problems of rock strength increase caused by high in-situ stress,the stress release method with rock slot in the bottom hole by an ultra-high-pressure water jet is proposed.The stress conditions of bottom... To solve the problems of rock strength increase caused by high in-situ stress,the stress release method with rock slot in the bottom hole by an ultra-high-pressure water jet is proposed.The stress conditions of bottom hole rock,before and after slotting are analyzed and the stress release mechanism of slotting is clarified.The results show that the stress release by slotting is due to the coupling of three factors:the relief of horizontal stress,the stress concentration zone distancing away from the cutting face,and the increase of pore pressure caused by rock mass expansion;The stress concentration increases the effective stress of rock along the radial distance from O.6R to 1R(R is the radius of the well),and the presence of groove completely releases the stress,it also allows the stress concentration zone to be pushed away from the cutting face,while significantly lowering the value of stresses in the area the drilling bit acting,the maximum stress release efficiency can reach 80%.The effect of slotting characteristics on release efficiency is obvious when the groove location is near the borehole wall.With the increase of groove depth,the stress release efficiency is significantly increased,and the release range of effective stress is enlarged along the axial direction.Therefore,the stress release method and results of simulations in this paper have a guiding significance for best-improving rock-breaking efficiency and further understanding the technique. 展开更多
关键词 Hard rock SLOTTING Stress release Down hole pressures Poroelastic mechanics Fluid-structure Interaction Ultra-high-pressure water jet
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Numerical Study on Mechanism of Blast-Induced Damage Considering Guiding Effect of Water Jet Slot
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作者 Dengfeng Su Zizheng Jia +3 位作者 Qiang Zhu Zhengguo Li Banghong Chen Dandan Zheng 《Structural Durability & Health Monitoring》 EI 2023年第3期209-224,共16页
Damage is one of the most important characteristics of rock failure.Studying the damage mechanism of rock blasting under the guiding effect of the water jet slot and revealing the mechanism of controlled blasting with... Damage is one of the most important characteristics of rock failure.Studying the damage mechanism of rock blasting under the guiding effect of the water jet slot and revealing the mechanism of controlled blasting with water jet assistance are crucial.In this study,a rock-like material was chosen as the research object for the calibration experiment of the numerical model.The numerical simulation models were then established by ANSYS/LS-DYNA,and the blastinduced damage mechanism under the guiding effect of the water jet slot was analyzed according to the blasting theory.The results indicated that explosive energy accumulates toward the direction of the slot as the guiding effect of the water jet slot,which allows the rock mass in the direction of the slot bear more damage.Meanwhile,the rock mass in the middle of the connection line between two blast-holes bears more damage under the combination of the effect of the explosion stress wave and guiding effect of water the jet slot on the detonation gas during double-slotted borehole blasting,which results in the formation of a gourd-shaped blast-induced damage area.In addition,the influence of the water jet slot on blast-induced damage varies depending on the blasting-process stage. 展开更多
关键词 Blast-induced damage rock-like material water jet slot ANSYS/LS-DYNA
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A Theoretical Study of Rock Drilling with a High Pressure Water Jet 被引量:4
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作者 倪红坚 王瑞和 《Petroleum Science》 SCIE CAS CSCD 2004年第4期72-76,共5页
Based on analyses of experimental results of water jet drilling, the fluid motion law in rock pores and the tendency of energy distribution, the rock-breaking process under high pressure water jet drilling has been s... Based on analyses of experimental results of water jet drilling, the fluid motion law in rock pores and the tendency of energy distribution, the rock-breaking process under high pressure water jet drilling has been studied systematically. The research indicates that the main interaction between the rock and water jet is interface coupling, that the impacting load and the static pressure of the water jet act together to make the rock break, and that the stress wave is the main factor. Water jet drilling can be divided into two stages: At the initial stage, the stress wave plays the main role and most of the rock breaking takes place; at the later stage, the existing rock defects, for instance, micro-holes and micro-cracks, are propagated and merged to make macroscopic damage, and then the diameter of the jet-drilled hole is expanded. 展开更多
关键词 water jet ROCK fluid-wall interaction DRILLING
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Testing and Analysis of the Speed of Water Jet in Water Jet Looms
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作者 李克让 麻伟巍 陈明 《Journal of Donghua University(English Edition)》 EI CAS 2003年第1期4-7,共4页
In the water jet looms, the distribution of the speed of water jet at the axis of the shed and its regularity are obtained by the Laser Doppler Tester. Based on the above, the water jet system is analyzed and the main... In the water jet looms, the distribution of the speed of water jet at the axis of the shed and its regularity are obtained by the Laser Doppler Tester. Based on the above, the water jet system is analyzed and the main effective approaches to increase the filling insertion rate and to widen the reed space of the loom are pointed out. 展开更多
关键词 Laser Doppler Tester the speed of the water jet water jet looms.
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Application of high-pressure water jet technology and the theory of rock burst control in roadway 被引量:19
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作者 Yang Zengqiang Dou Linming +3 位作者 Liu Chang Xu Mengtang Lei Zhen Yao Yahu 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第5期929-935,共7页
This paper puts forward using high-pressure water jet technology to control rock burst in roadway, and analyzes the theory of controlling rock burst in roadway by the weak structure zone model. The weak structure zone... This paper puts forward using high-pressure water jet technology to control rock burst in roadway, and analyzes the theory of controlling rock burst in roadway by the weak structure zone model. The weak structure zone is formed by using high-pressure water jet to cut the coal wall in a continuous and rotational way. In order to study the influence law of weak structure zone in surrounding rock, this paper numerically analyzed the influence law of weak structure zone, and the disturbance law of coal wall and floor under dynamic and static combined load. The results show that when the distance between high-pressure water jet drillings is 3 m and the diameter of drilling is 300 mm, continuous stress superposition zone can be formed. The weak structure zone can transfer and reduce the concentrated static load in surrounding rock, and then form distressed zone. The longer the high-pressure water jet drilling is, the larger the distressed zone is. The stress change and displacement change of non-distressed zone in coal wall and floor are significantly greater than that of distressed zone under dynamic and static combined load. And it shows that the distressed zone can effectively control rock burst in roadway under dynamic and static combined load. High-pressure water jet technology was applied in the haulage gate of 250203 working face in Yanbei Coal Mine, and had gained good effect. The study conclusions provide theoretical foundation and a new guidance for controlling rock burst in roadway. 展开更多
关键词 High-pressure water jet technology Rock burst Weak structure zone Dynamic and static combined load
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Research and application of water jet technology in well completion and stimulation in China 被引量:10
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作者 Li Gensheng Huang Zhongwei Tian Shouceng Shen Zhonghou 《Petroleum Science》 SCIE CAS CSCD 2010年第2期239-244,共6页
In recent years, rapid progress in the use of high pressure water jets (HPWJ) has been made in oil and gas well drilling, completion, and stimulation; and good results have been achieved in field applications. Advan... In recent years, rapid progress in the use of high pressure water jets (HPWJ) has been made in oil and gas well drilling, completion, and stimulation; and good results have been achieved in field applications. Advances in technologies and developments of well completion and stimulation with hydrajet are reviewed in this paper. Experiments were conducted to study the characteristics of abrasive water jetting and to optimize jet parameters, which can provide methods for the well completion and hydrajet fracturing. Deep-penetrating hydrajet perforating can create a 2-3 m clean hole with a diameter of 20-35 mm. Multilayer hydrajet fracturing is a process whereby multiple layers are stimulated in a single run without using mechanical packers, thereby reducing operation procedure and risk. Multilateral radial wells can be drilled using hydraulic jetting up to 100 m in length. The technique to remove sand particles and plugs with rotating self-resonating cavitating water jets in horizontal wellbores has been developed and oilfield-tested, which shows promising, cost effective prospects. 展开更多
关键词 water jet abrasive jet well completion PERFORATION STIMULATION horizontal drilling with hydrajet
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Multiphase Flow and Wear in the Cutting Head of Ultra-high Pressure Abrasive Water Jet 被引量:8
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作者 YANG Minguan WANG Yuli KANG Can YU Feng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2009年第5期729-734,共6页
Abrasive water jet cutting technology is widely applied in the materials processing today and attracts great attention from scholars, but many phenomena concerned are not well understood, especially in the internal je... Abrasive water jet cutting technology is widely applied in the materials processing today and attracts great attention from scholars, but many phenomena concerned are not well understood, especially in the internal jet flow of the cutting head at the condition of ultra-high pressure. The multiphase flow in the cutting head is numerically simulated to study the abrasive motion mechanism and wear inside the cutting head at the pressure beyond 300 MPa. Visible predictions of the particles trajectories and wear rate in the cutting head are presented. The influences of the abrasive physical properties, size of the jewel orifice and the operating pressure on the trajectories are discussed. Based on the simulation, a wear experiment is carried out under the corresponding pressures. The simulation and experimental results show that the flow in the mixing chamber is composed of the jet core zone and the disturbance zone, both affect the particles trajectories. The mixing efficiency drops with the increase of the abrasive granularity. The abrasive density determines the response of particles to the effects of different flow zones, the abrasive with medium density gives the best general performance. Increasing the operating pressure or using the jewel with a smaller orifice improves the coherency of p articles trajectories but increases the wear rate of the jewel holder at the same time. Walls of the jewel holder, the entrance of the mixing chamber and the convergence part of the mixing tube are subject to wear out. The computational and experimental results give a qualitative consistency which proves that this numerical method can provide a reliable and visible cognition of the flow characteristics of ultra-high pressure abrasive water jet. The investigation is benefit for improving the machining properties of water jet cutting systems and the optimization design of the cutting head. 展开更多
关键词 abrasive water jet cutting head multiphase flow WEAR
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Mechanism and numerical simulation of pressure stagnation during water jetting perforation 被引量:6
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作者 Huang Zhongwei Li Gensheng Tian Shouceng Shen Zhonghou Luo Hongbin 《Petroleum Science》 SCIE CAS CSCD 2008年第1期52-55,共4页
When perforating with an abrasive water jet, it is possible that the pressure in the hole (perforation) will be higher than that in the annulus because of water jet blasting against the hole wall, which also is the ... When perforating with an abrasive water jet, it is possible that the pressure in the hole (perforation) will be higher than that in the annulus because of water jet blasting against the hole wall, which also is the theoretical basis for the technology of hydro-jet fracturing. This paper analyzes the mechanism of generating pressure stagnation in water jet hole, and puts forward a new concept of hydroseal. Then, the distribution of pressure in the hole was simulated with the finite element method. The simulation results showed that the pressure in the hole was higher than that in the annulus. Also, the lower the annular pressure (confining pressure) and the higher the blasting pressure, the greater the pressure difference. An experiment indicated that the cement sample was lifted up under the pressure stagnation in the hole, which proved the finite element simulation results obviously. 展开更多
关键词 water jet PERFORATION pressure stagnation hydro-seal MECHANISM
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Experimental Study on Reaction Thrust Characteristics of Water Jet for Conical Nozzle 被引量:6
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作者 黄国勤 李晓辉 +1 位作者 朱玉泉 聂松林 《China Ocean Engineering》 SCIE EI 2009年第4期669-678,共10页
Water jet thruster, which is a marine system that creates a jet of water for propulsion, has several advantages such as low noise, good anti-cavitation characteristics and maneuvering characteristics. The reaction thr... Water jet thruster, which is a marine system that creates a jet of water for propulsion, has several advantages such as low noise, good anti-cavitation characteristics and maneuvering characteristics. The reaction thrust characteristics of water jet for conical nozzles directly determine the speed of autonomous underwater vehicles (AUV). Theoretical, numerical and experimental studies have been, carried out to investigate the effects of the nozzle geometries as well as inlet conditions on the reaction thrust of water jet in this paper. The experimental results show that: 1) the reaction thrust is proportional to inlet pressure, the square of flow rate and 2/3 power exponent of input power; 2) the diameter of cylinder column for conical nozzle has great influence on the reaction thrust characteristics; 3) the best values of the half cone angle and the cylinder column length exist to make the reaction thrust coefficient to reach the maximum under the same inlet conditions. Those provide a basis for nozzles design and have significant value, especially for developing high performance and efficiency water jet propulsion unit. 展开更多
关键词 conical nozzle reaction thrust thrust coefficient water jet
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A Study of the Rock Breaking Mechanism during Swirling Water Jet Drilling 被引量:6
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作者 NiHongjian WangRuihe 《Petroleum Science》 SCIE CAS CSCD 2004年第1期39-44,共6页
Based on an analysis of the factors affecting rock breaking and the coupling between rock and fluid during water jet drilling, the rock damage model and the damage-coupling model suitable for the whole rock breaking p... Based on an analysis of the factors affecting rock breaking and the coupling between rock and fluid during water jet drilling, the rock damage model and the damage-coupling model suitable for the whole rock breaking process under the water jet is established with continuous damage mechanics and micro-damage mechanics. The evolvement of rock damage during swirling water jet drilling is simulated on a nonlinear FEM and dynamic rock damage model, and a decoupled method is used to analyze the rock damage. The numerical results agree with the test results to a high degree, which shows the rock breaking ability of the swirling water jet is strong. This is because the jet particle velocity of the swirling water jet is three-dimensional, and its rock-breaking manner mainly has a slopping impact. Thus, the interference from returning fluid is less. All these aspects make it easy to draw and shear the rock surface. The rock breaking process is to break out an annular on the rock surface first, and then the annular develops quickly in both the radial and axial directions, the last part of the rock broken hole bottom is a protruding awl. The advantage of the swirling water jet breaking rock is the heavy breaking efficiency,large breaking area and less energy used to break rock per unite volume, so the swirling water jet can drill in a hole of a large diameter. 展开更多
关键词 Swirling water jet rock damage damage mechanism finite element method
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Rock Breaking Performance of a Pick Assisted by High-pressure Water Jet under Different Configuration Modes 被引量:5
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作者 LIU Songyong LIU Xiaohui +1 位作者 CHEN Junfeng LIN Mingxing 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第3期607-617,共11页
In the process of rock breaking, the conical pick bears great cutting force and wear, as a result, high-pressure water jet technology is used to assist with cutting. However, the effect of the water jet position has n... In the process of rock breaking, the conical pick bears great cutting force and wear, as a result, high-pressure water jet technology is used to assist with cutting. However, the effect of the water jet position has not been studied for rock breaking using a pick. Therefore, the models of rock breaking with different configuration modes of the water jet are established based on SPH combined with FEM. The effect of the water jet pressure, distance between the jet and the pick bit, and cutting depth on the rock breaking performance as well as a comparison of the tension and compression stress are studied via simulation; the simulation results are verified by experiments. The numerical and experimental results indicate that the decrease in the rates of the pick force obviously increases from 25 MPa to 40 MPa, but slowly after 40 MPa, and the optimal distance between the jet and the pick bit is 2 mm under the JFP and JSP modes. The JCP mode is proved the best, followed by the modes of JRP and JFP, and the worst mode is JSP. The decrease in the rates of the pick force of the JCP, JRP, JFP, and JSP modes are up to 30.96%, 28.96%, 33.46%, 28.17%, and 25.42%, respectively, in experiment. Moreover, the JSP mode can be regarded as a special JFP model when the distance between the pick-tip and the jet impact point is 0 mm. This paper has a dominant capability in introducing new numerical and experimental method for the study of rock breaking assisted by water jet and electing the best water jet position from four different configuration modes. 展开更多
关键词 conical pick high pressure water jet rock breaking SPH
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Energy Consumption in Comminution of Mica with Cavitation Abrasive Water Jet 被引量:12
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作者 GUO Chu-wen DONG Lu 《Journal of China University of Mining and Technology》 EI 2007年第2期251-254,共4页
We have studied the efficiency of energy consumption in the comminution of mica powder with cavitation abrasive water jet technology. The energy required to create new surfaces in the comminution of mica powder with c... We have studied the efficiency of energy consumption in the comminution of mica powder with cavitation abrasive water jet technology. The energy required to create new surfaces in the comminution of mica powder with cavitation abrasive water jet was calculated,in order to estimate its efficiency of energy consumption. The particle size distribution and the specific surface area were measured by applying a JEM-200CX transmission electron microscope and an Autosorb-1 automatic surface area analyzer. The study results show that the efficiency of energy consumed in creating new surface areas is as high as 2.92%,or 4.94% with the aid of cavitation in the comminution of mica powder. This efficiency will decrease with an increase in the number of comminutions. After three comminutions,the efficien-cies will become 1.91% and 2.29% for comminution without cavitation and with cavitation,respectively. The abrasive water jet technology is an effective way for comminution of mica powder. 展开更多
关键词 energy consumption comminution MICA cavitation abrasive water jet
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Portable mixed abrasive water jet equipment for rescue in high gas mine shaft 被引量:7
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作者 ZENG Rui DU Chang-long +1 位作者 XU Rui ZHAO Jing 《Journal of Coal Science & Engineering(China)》 2011年第2期207-211,共5页
In order to rescue a trapped miner and clean out roadways quickly in a high gas mine shaft after a mining mishap, a special portable cold-cutting equipment is needed, the main technology parameters were calculated acc... In order to rescue a trapped miner and clean out roadways quickly in a high gas mine shaft after a mining mishap, a special portable cold-cutting equipment is needed, the main technology parameters were calculated according to the advanced cold-cutting technology of high pressure abrasive water jet and the portable mixed abrasive water jet equipment (PAWE) was designed to meet the needs of emergency rescue in high gas mine shafts. Tested the PAWE in a high gas environment, and the result shows that the maximum cutting depth of solid iron pipe is 18 mm and the recoilforce of the sprayer is 28.9 N under the conditions that actual cutting pressure is 29 MPa, starting target distance is 10 ram, cutting speed is 180 mm/min and concentration of abrasive is 32%. The course of the experiment in the high gas environment was smooth and continuous, without any explosion. The PAWE is easy to move and operate, but the nozzle which was worn badly in the sprayer should be changed every 8 minutes. 展开更多
关键词 PORTABLE ABRASIVE water jet emergency rescue GAS
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Numerical analysis on coal-breaking process under high pressure water jet 被引量:7
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作者 CHEN Jin-hua LIANG Yun-pei CHENG Guo-qiang 《Journal of Coal Science & Engineering(China)》 2009年第3期289-294,共6页
Based on the theory of nonlinear dynamic finite element,the control equation ofcoal and water jet was acquired in the coal breaking process under a water jet.The calculationmodel of coal breaking under a water jet was... Based on the theory of nonlinear dynamic finite element,the control equation ofcoal and water jet was acquired in the coal breaking process under a water jet.The calculationmodel of coal breaking under a water jet was established;the fluid-structure couplingof water jet and coal was implemented by penalty function and convection calculation.The dynamic process of coal breaking under a water jet was simulated and analyzed bycombining the united fracture criteria of the maximum tensile strain and the maximal shearstrain in the two cases of damage to coal and damage failure to coal. 展开更多
关键词 numerical analysis coal breaking high pressure water jet fluid-structure coupling DAMAGE DRILL
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Experiment and Numerical Simulation of Free Water Jet by a Central-body Nozzle 被引量:3
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作者 YANG Minguan ZHANG Feng KANG Can GAO Bo 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2010年第6期797-804,共8页
The recent research about cavitation jet mainly focuses on the organ-pipe nozzle and triangular nozzle. The research content mainly includes the optimized design about the structure of nozzles, the observation and flo... The recent research about cavitation jet mainly focuses on the organ-pipe nozzle and triangular nozzle. The research content mainly includes the optimized design about the structure of nozzles, the observation and flow analysis about the cavitation jet in the water, and the theory of rock attacked by the cavitation jet, while the energy characteristic of the free jet is not studied yet. In China, the research about the central-body nozzle is almost empty. For the purpose of studying the energy characteristic and the structure of free water jet discharged from central-body nozzle, an experiment with phase Doppler particle anemometry(PDPA) technology is carried out to measure the free water jet flow, which is produced by a central-body nozzle under the jet pressure of 15 MPa. While five sections with different axial distances from the nozzle outlet are selected for data process and analysis, the axial and radial velocity and the droplets of the particle size are studied. Meanwhile, numerical calculation of corresponding flow field is conducted by using volume of fluid(VOF) multiphase model, and the jet flow feature is discussed. The experimental and calculating results show that the axial velocity of high speed jet flow dissipates slowly in the air, and the core area and diffused area are discovered. The diameter of droplet in the core area is small, and jet energy is concentrated, while in the diffusion area, water is mingled with ambient air and radial velocity is relatively large. Obvious low-pressure area exists behind the central body and potential cavitation may occur in that area. The proposed research reveals the energy characteristic of free jet discharged from central-body nozzle, provides the theoretical basis for preestimating erosion feature of the central-body nozzle and also the theoretical foundation for revealing the mechanism of erosion. 展开更多
关键词 central-body nozzle free water jet phase Doppler particle anemometry(PDPA) energy characteristic VOF model
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Numerical Simulation Research of Liquid-Solid Two-Phase Flow in Abrasive Water Jet Nozzle 被引量:3
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作者 聂百胜 孟筠青 姬宗锋 《Journal of Beijing Institute of Technology》 EI CAS 2009年第2期157-161,共5页
According to the Lagrange discrete phase model of multiphase flow, mathematical model of the abrasive water-jet (AWJ) nozzle based on the multi-phase movement was introduced, then the boundary conditions was determi... According to the Lagrange discrete phase model of multiphase flow, mathematical model of the abrasive water-jet (AWJ) nozzle based on the multi-phase movement was introduced, then the boundary conditions was determined and the liquid-solid turbulence which is isothermal, can not be compressed and steadystate in the cone-cylinder nozzles of the export of the pre-mixed AWJ was simulated applying the software FLUENT. The results showed that: the axial velocity and dynamic pressure of the continuous phase in the nozzle were axial symmetry notable, and at the axis had a extreme point; abrasive accelerated at two points, in front contractive segment, the rate increased rapidly, and in the back straight one, the speed accelerated slowly. The length of the cylinder is 100 mm, the diameter of the nozzle is 8 mm, and the angle of the cone is 15°. There is a extreme point of the rate at the point 10 mm in the established model. The results of simulation laid the foundation for optimizing the nozzle structure, improving efficiency and developing the nozzle. 展开更多
关键词 water jet cutting ABRASIVE NOZZLE numerical simulation
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Impingement capability of high-pressure submerged water jet: Numerical prediction and experimental verification 被引量:3
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作者 刘海霞 邵启明 +1 位作者 康灿 龚辰 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第10期3712-3721,共10页
At jet pressures ranging from 80 to 120 MPa, submerged water jets are investigated by numerical simulation and experiment. Numerical simulation enables a systematic analysis of major flow parameters such as jet veloci... At jet pressures ranging from 80 to 120 MPa, submerged water jets are investigated by numerical simulation and experiment. Numerical simulation enables a systematic analysis of major flow parameters such as jet velocity, turbulent kinetic energy as well as void fraction of cavitation. Experiments facilitate an objective assessment of surface morphology, micro hardness and surface roughness of the impinged samples. A comparison is implemented between submerged and non-submerged water jets. The results show that submerged water jet is characterized by low velocity magnitudes relative to non-submerged water jet at the same jet pressure. Shear effect serves as a key factor underlying the inception of cavitation in submerged water jet stream. Predicted annular shape of cavity zone is substantiated by local height distributions associated with experimentally obtained footprints. As jet pressure increases, joint contribution of jet kinetic energy and cavitation is demonstrated. While for non-submerged water jet, impingement force stems exclusively from flow velocity. 展开更多
关键词 submerged water jet CAVITATION shear effect impingement test micro hardness surface morphology
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Numerical simulation of bubble chaotic motion in a cavitating water jet 被引量:5
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作者 卢义玉 《Journal of Chongqing University》 CAS 2003年第1期91-94,共4页
A computational fluid dynamics (CFD) method is developed to investigate the radical motion of single cavitating bubble in the oscillating pressure field of a cavitating water jet. Regarding water as a compressible flu... A computational fluid dynamics (CFD) method is developed to investigate the radical motion of single cavitating bubble in the oscillating pressure field of a cavitating water jet. Regarding water as a compressible fluid, the simulation is performed at different oscillating frequencies. It is found that the bubble motion presents obvious nonlinear feature, and bifurcation and chaos appear on some conditions. The results manifest the indetermination of the cavitating bubble motion in the oscillating pressure field of the cavitating water jet. 展开更多
关键词 cavitating water jet cavitating bubble motion numerical simulation
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