Micro-mechanism study on rock breaking behavior under water jet impact using coupled SPH-FEM/DEM method with Voronoi grains

2019 ◽  
Vol 108 ◽  
pp. 472-483 ◽  
Author(s):  
Zhijun Wu ◽  
Fangzheng Yu ◽  
Penglin Zhang ◽  
Xuewei Liu
Keyword(s):  
Rock Breaking ◽  
Water Jet ◽  
Mechanism Study ◽  
Jet Impact

scholarly journals Study on Rock-Breaking Depth and Damage Area under Particle Jet Impact

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Fushen Ren ◽  
Tiancheng Fang ◽  
Xiaoze Cheng
Keyword(s):  
Mathematical Model ◽  
Impact Velocity ◽  
Particle Diameter ◽  
Rock Breaking ◽  
Water Jet ◽  
Experimental Results ◽  
Damage Area ◽  
Jet Impact ◽  
Mathematical Calculation ◽  
The Mathematical Model

Particle jet impact drilling technology is an efficient method which mainly uses high-velocity particles to break rock. As the important criterion for evaluating rock-breaking effect, rock-breaking depth and damage area were studied in this paper. Firstly, a particle jet impact rock-breaking test device was developed, and laboratory experiments have been carried out. Then, based on the spherical cavity expansion theory, the mathematical model of rock-breaking depth and damage area under particle jet impact was established. Afterward, the effect of water-jet impact velocity, impact angle, and particle diameter on rock-breaking depth and damage area was analyzed by comparing experimental results and mathematical calculation. The results show that rock-breaking depth and damage area would increase with increase of water-jet impact velocity and decrease slightly with increase of particle diameter. And the combination of 8° and 20° is recommended for nozzle layout. The experimental results and mathematical calculation are basically consistent, which could verify the correctness of the mathematical model. The study has significance for development and application of particle jet impact rock-breaking technology and perfection of theoretical research.

scholarly journals Rock-Breaking Properties Under the Rotatory Impact of Water Jets in Water Jet Drilling

2019 ◽  
Vol 9 (24) ◽  
pp. 5417 ◽  
Author(s):  
Zhaolong Ge ◽  
Lei Wang ◽  
Man Wang ◽  
Zhe Zhou ◽  
Songqiang Xiao ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Rotation Speed ◽  
Impact Angle ◽  
Rock Breaking ◽  
Water Jet ◽  
Drill Bit ◽  
Rock Breakage ◽  
Jet Impact ◽  
Tension State ◽  
Optimum Water

Water jet drilling is widely used to develop coalbed methane reservoirs. The water jet drill bit is the core component, and a self-rotating bit is an economical bit because of its high rock-breaking efficiency and low energy consumption. Because the important parameters concerning the rock-breaking efficiency of these drill bits are unclear, this study carried out rock-breaking experiments on water jet rotation under different conditions of drill bit rotation speed, jet pressure, and jet impact angle. How the rock was fractured and eroded under these different conditions was analyzed. The results show that the volume of rock broken under rotary jet erosion increases exponentially with increasing jet pressure. The rock-breaking depth is the most important factor that influences the volume of rock broken, whereas the diameter of the area broken is a secondary factor. There is an optimum water jet rotation speed for the most efficient rock breakage, and this rotation speed is positively correlated with jet pressure. There is also an optimum water jet impact angle for rock breaking, and, in our experiments, this angle was 10°. The rotary impact of the water jet causes the rock to be in a three-way tension state, and this reduces the water cushion effect and jet reflection. This study can be used as a reference and guide for optimizing the design of self-rotating water jet bits and the determination of reasonable drilling parameters.

scholarly journals Numerical Investigation of Rock Breaking Mechanisms by High Pressure Water Jet

2015 ◽  
Vol 126 ◽  
pp. 295-299 ◽  
Author(s):  
Hailong Chen ◽  
Zhaomin Li ◽  
Zhihan Gao ◽  
Yuanyuan Sun
Keyword(s):  
High Pressure ◽  
Numerical Investigation ◽  
Rock Breaking ◽  
Water Jet ◽  
Pressure Water ◽  
High Pressure Water Jet

scholarly journals Modelling of water jet impact on molten metal

2021 ◽  
Vol 2119 (1) ◽  
pp. 012073
Author(s):  
S E Yakush ◽  
N S Sivakov ◽  
V I Melikhov ◽  
O I Melikhov
Keyword(s):  
Steam Explosion ◽  
Water Jet ◽  
Point Of View ◽  
Change Model ◽  
Water Pool ◽  
Jet Impact ◽  
Melt Water ◽  
Height Dependence ◽  
The Impact ◽  
Primary Melt

Abstract Splashes of high-temperature melt spreading over a water pool bottom can be a reason for the formation of a zone where melt, water and steam are mixed, providing conditions for powerful steam explosions. The paper considers the formation of melt splashes arising from the impact of a water jet on the surface of the melt. Numerical simulations are performed in 3D formulation, using the VOF method and an improved phase change model. The evolution of melt surface following the water jet impact is demonstrated, including the formation of a cavern, a primary melt splash known as the crown, as well as a secondary splash following the collapse of the cavern, known as the cumulative jet. Parametric study for the melt splash height dependence on the water jet geometry and velocity is carried out. The results of numerical analysis are discussed from the point of view of the similarity with respect to the momentum and kinetic energy of water jet. The significance of the results for the steam explosion problem is discussed.

scholarly journals Rock Breaking Performance of TBM Disc Cutter Assisted by High-Pressure Water Jet

2020 ◽  
Vol 10 (18) ◽  
pp. 6294
Author(s):  
Fengchao Wang ◽  
Dapeng Zhou ◽  
Xin Zhou ◽  
Nanzhe Xiao ◽  
Chuwen Guo
Keyword(s):  
High Pressure ◽  
Hard Rock ◽  
Rock Breaking ◽  
Water Jet ◽  
Disc Cutter ◽  
Pressure Water ◽  
High Pressure Water Jet ◽  
Full Face ◽  
Rock Tunnel ◽  
Digging Efficiency

A high-pressure water jet can break rock efficiently, which is of great potential to overcome the problems of a tunnel boring machine (TBM) in full-face hard rock tunnel digging, such as low digging efficiency and high disc cutter wear rate. Therefore, this paper presented a new tunneling method that is a TBM coupled with a high-pressure water jet. The rock failure mechanism under the coupled forces of a disc cutter and water jet was analyzed at first. Then, the finite element method (FEM) and smoothed particle hydrodynamics (SPH) method were used to establish a numerical model of rock broken by the disc cutter and water jet. Effects of parameters on rock breaking performance were studied based on the numerical model. Moreover, an experiment of the water jet cutting marble was carried out to verify the reliability of the numerical simulation. Results showed that the high-pressure water jet can increase the TBM digging efficiency and decrease the forces and wear rate of the disc cutter. The optimum nozzle diameter is 1.5 mm, while the optimum jet velocity is 224.5 m/s in this simulation. The results can provide theoretical guidance and data support for designing the most efficient system of a TBM with a water jet for digging a full-face hard rock tunnel.

An Experimental Study of the Abrasive Water Jet Micro-Machining Process for Quartz Crystals

2012 ◽  
Vol 565 ◽  
pp. 339-344 ◽  
Author(s):  
H. Qi ◽  
J.M. Fan ◽  
Jun Wang
Keyword(s):  
Experimental Study ◽  
Removal Rate ◽  
Water Jet ◽  
Machining Process ◽  
Bottom Surface ◽  
Micro Machining ◽  
Abrasive Water Jet ◽  
Process Variables ◽  
Jet Impact ◽  
Micro Channels

An experimental study of the machining process for micro-channels on a brittle quartz crystal material by an abrasive slurry jet (ASJ) is presented. A statistical experiment design considering the major process variables is conducted, and the machined surface morphology and channelling performance are analysed to understand the micro-machining process. It is found that a good channel top edge appearance and bottom surface quality without wavy patterns can be achieved by employing relatively small particles at shallow jet impact angles. The major channel performance measures, i.e. material removal rate (MRR) and channel depth, are then discussed with respect to the process parameters. It shows that with a proper control of the process variables, the abrasive water jet (AWJ) technology can be used for the micro-machining of brittle materials with high quality and productivity.

Non-Traditional Machining Using Pulsed Water Drops

2004 ◽  
Author(s):  
M. J. Jackson
Keyword(s):  
Experimental Data ◽  
Plane Surface ◽  
Water Jet ◽  
Surface Cracks ◽  
Response Characteristics ◽  
Water Jets ◽  
Jet Impact ◽  
Water Drops ◽  
Pulsed Water Jet ◽  
Traditional Manner

This paper discusses water jet machining of selected materials using a non-traditional way of delivering water jets in the form of a series of discrete pulses. The theory of water jet impact has been used to demonstrate the principle of removing material by exploiting the existence of a Rayleigh wave that excites the formation of surface cracks and the lateral outflow of water that extends the cracks and removes material. A mathematical model has been developed that predicts changes in the response characteristics of materials owing to an idealised representation of a finite jet of water impacting a plane surface. The analytical approach used is applicable to the first stages of impact where the compressibility of water in the droplet is significant. The predicted response characteristics are compared with experimental data generated using controlled water jet impacts produced by a specially constructed pulsed water jet machining centre. The predicted response of selected materials compare well with experimental data. The results presented in this paper illustrate the importance of using pulsed water jets as a way of machining materials in a non-traditional manner.

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