High-pressure Water Jet Technology Research Articles

Research on High-Pressure Water Jet Interference for Collision Prevention of Waterway Viaduct Piers: Case Study of Guangzhou Lixinsha Bridge

In this paper, with the frequent occurrence of ship–bridge collision accidents as the context and the collision accident of the Lixinsha Bridge in China as the background, the scenario of a ship impacting a pier was simulated using ANSYS-FLUENT software, and the practical application possibility of the high-pressure water jet interference (HPWJI) anti-collision method was thoroughly investigated. Through the simulation analysis, the effectiveness of a high-pressure water jet with a total flow rate of 45 m3/s in altering the navigation direction of large-tonnage (2000 t) ships and avoiding obstacles was verified. Additionally, its impact on the stress of the ship steel plates and navigation status was also explored. It was found that, with reasonable layout and parameter adjustment, the high-pressure water jet technology could effectively intervene in the ship’s navigation trajectory while ensuring the structural safety of the ship, with minimal impact on the ship’s navigation stability and passenger comfort. Furthermore, the injection angle of the high-pressure water jet had a significant impact on the deflection and deceleration of the ship. Specifically, when the water jet impacted the ship along its forward direction, it could effectively increase the ship’s deceleration and deflection time, reducing the speed from 2.55 m/s to 1.7 m/s, a decrease of approximately 33%, significantly enhancing collision prevention effectiveness. This research provides important guidance for the practical application of high-pressure water jet collision prevention technology and is of great significance for improving the safety of waterway transportation.

Morphological study of cortical bone damage caused by high-pressure water jet erosion based on SPH-FEM coupling algorithm

Currently, traditional processing methods such as drilling, sawing, and milling are primarily utilized in orthopedic surgery, generating a significant amount of heat during the cutting process, leading to irreversible damage to bone and surrounding tissues. High-pressure water jet technology has demonstrated the capability to effectively reduce cutting temperatures and prevent thermal damage during the cutting process. It holds promising potential as an alternative approach to traditional surgical techniques in orthopedic surgery. This study selected the SPH-FEM (Smoothed particle hydrodynamics-Finite element method) coupling algorithm and LS-DYNA software to simulate the effects of high-pressure water jet erosion on cortical bone. The study analyzed the impact of jet pressure on damage morphology and the degree of cortical bone breakage. The simulation results indicate that the concave section of cortical bone damaged by high-pressure water jet is “U” shape. The maximum damage depth of cortical bone increases with the increase in jet pressure. Specifically, as jet pressure increases from 80 MPa to 245 MPa, the increase rate of the average cortical bone damage depth increased from about 0.01 mm/s to more than 0.45 mm/s. The beginning of the concave section of cortical bone damage presents a “funnel” shape, and the width of cortical bone damage reaches its maximum. When the jet pressure is below 180 MPa, there is a significant fluctuation in the width of cortical bone damage. However, with increasing jet pressure, the fluctuation lessens. Physical experiments were carried out under identical technological parameters to verify the numerical results. The experimental results are basically consistent with the numerical results, which can provide a theoretical basis for improving the surface quality of jet erosion of cortical bone.

Flow Field Simulation and Nozzle Parameter Optimization of Rust Removal Robot Based on High-Pressure Water Jet Technology

To enhance the safety and longevity of large ships, employing high-pressure water jet technology for rust removal is crucial in this article, the qualitative relationship among the key parameters of high-pressure water jet rust removal is analyzed theoretically. Secondly, the flow field simulation is carried out using Computational Fluid Dynamics (CFD) software to verify the relationship among the key parameters. Finally, the influence of different nozzle length-diameter ratios on jet characteristics is analyzed. The simulation results show that the nozzle end length is 0 mm and the nozzle diameter is 1mm for the straight-cone convergent nozzle with a shrinking angle of 30° when the diameter of the length-diameter ratio remains unchanged and the length of the nozzle end is changed. Simultaneously, the highest values are observed for the nozzle exit velocity and the impact force on the target surface. The impact range of target shear force takes the maximum value when the length-diameter ratio is 1. Further, by changing the length of the nozzle-end and the nozzle diameter in the length-diameter ratio, the influence on the jet characteristics can be concluded that the nozzle diameter has a greater influence on the nozzle exit velocity than the nozzle-end length. On this basis, the optimized nozzle parameters can be obtained i.e., the nozzle-end length is 1 mm and the nozzle diameter is 1 mm, such that the effective striking area of the jet is the largest and the striking effect is the best.

Influence of the cutting edge preparation of carbide punching tools for punching of ultra-high strength steel strips

In order to ensure a robust punching process of ultra-high strength steel spring strips using carbide punching tools, a high stability of the cutting edge is required. Here the cutting edge preparation process has a significant influence. In the presented study, high-pressure abrasive water jet technology for cutting edge preparation was designed, investigated and analysed. For defining the optimal cutting edge shape regarding stresses, a numerical analysis using LS-DYNA was conducted. Within this analysis, the influence of the cutting edge rounding and symmetry was numerically tested and evaluated. Based on the results, two cutting edge shapes were selected and prepared using the high-pressure abrasive water injection jet technology. The tools were applied in the punching process up to 50,000 strokes in order to analyse the cutting performance and tool wear. With regard to a highly wear resistant tool for punching, a combination of the abrasive water injection jet preparation routine and a CVD diamond coating are under further investigation and first insights are presented additionally.

Analysis of Rock Breaking Parameters and Simulation of Mechanical Characteristics of Multi-Nozzle Jet Impact

With the continuous development of high-pressure water jet technology, research on the optimization of structural parameters for multi-nozzle configurations, the perforation effect of jet rotational impact rock breaking, and the impact force during rock breaking has received increasing attention. Through the development of a self-designed high-pressure water jet rotational drilling test device, rock breaking experiments were conducted on sandstone of different strengths using jet streams with different inclination angles, various combinations of nozzles, different target distances, and different rotational speeds. The parameters and structure of the multi-nozzle jet drill bit were optimized, and the impact of water jet-rock breaking effects was studied. The rationality of different inclination-angle jet streams in rock breaking was verified using the ALE-FEM coupling method. The changes in the force on the target body and the fragmentation mode during rock breaking with different inclination-angle jet streams were analyzed. The results showed that under the condition of adjustable inclination angles, a smaller inclination angle resulted in greater depth and a smaller diameter of rock breaking, while a larger inclination angle resulted in greater width and a smaller depth of rock breaking. The optimal combination of multi-nozzle jet streams was determined to be 20°, 30°, and 60°, which achieved a balance between rock breaking and borehole expansion performance. The efficiency of multi-nozzle jet rotational rock breaking decreased with increasing target distance, with the optimal range being 2 to 4 mm. The rotational speed of the multi-nozzle jet stream had a significant impact on rock-breaking efficiency. Under the same target distance conditions, as the drilling speed increased, the volume of rock breaking initially increased and then decreased, and the rate of volume attenuation increased with increasing target distance. The forms of rock breaking in multi-nozzle jet streams were not identical. Jet streams with smaller inclination angles mainly caused tensile failure through axial impact, while those with larger inclination angles primarily caused shear failure through radial impact. This study provides valuable guidance for optimizing the structural parameters of multi-nozzle jet drill bits and researching rotational rock breaking.

Coal breaking characteristics of high pressure water jet and the law of coordinated pressure relief of slits

Hydraulic fracturing creates slots on the coal surface through the impact of high-pressure water jets, resulting in stress gradients in the surrounding coal, thereby inducing stress release and increasing gas extraction efficiency. It is an effective measure to prevent coal and gas outbursts. Numerical simulations demonstrate that high-pressure water jets generate slots in the coal, leading to stress gradients in the surrounding coal. These stress gradients drive the coal to move gradually towards the slots, thereby releasing stress. The stress unloading degree in the Y direction is greater than that in the X and Z directions. Damage occurs in the coal near the slots, causing a significant increase in the number of fractures within the coal, which improves gas extraction efficiency. The study reveals the variation in stress unloading of coal between hydraulic fracturing boreholes and extraction boreholes in adjacent positions. By cross-referencing various factors in numerical simulations, the extent of damage in different directions caused by slot formation under different factor combinations is determined. A mathematical model for the range of coal damage surrounding the slots is obtained through MATLAB fitting. The research findings provide references for on-site testing and applications of high-pressure water jet technology.

Optimization of Destressing Parameters of Water Jet Slits in Rock Burst Coal Seams for Deep Mining

Mining in deep coal seams is characterized by high ground stress, often accompanied by coal and rock dynamic disasters such as rock bursts. High-pressure water jet slotting technology can relieve pressure and reduce the stress concentration on the coal seam, which is one of the effective pressure relief measures in rock burst coal seams for deep mining. Reasonable pressure relief parameters are an important influence on the effectiveness of pressure relief achieved by a high-pressure water jet. This paper uses theoretical analysis and numerical simulation to analyze the principle of high-pressure water jet pressure relief and rock burst prevention, and a theoretical calculation model of six key pressure relief parameters is constructed. The optimal values of each pressure relief parameter are obtained, and good pressure relief effect is achieved in a certain rock burst risk area. The research results showed that (1) parameters such as drilling spacing–slit radius, drilling depth–slit length, and slotting cutting spacing–slotting cutting width have a great influence on the pressure relief effect, and there is a significant interaction between the parameters, while the strength of the coal seam also has a significant effect on the selection of the parameters and the pressure relief effect. (2) The displacement, vertical stress, plastic zone, elastic energy, impact risk index, and the cost of pressure relief can be used to comprehensively evaluate the quality and economy of the pressure relief effect, and the optimal pressure relief parameters of high-pressure water jet slotting under specific physical force properties of the coal seam can be obtained. (3) High-pressure water jet technology with optimal pressure relief parameters was applied to No. 3 connecting the roadway in the 730 mining area of a mine studied, and field monitoring showed that indicators such as microseismic frequency, total energy, and spatial concentration significantly decreased. Moreover, the accuracy of the theoretical model of high-pressure water jet slotting pressure relief parameter optimization is reliable in the relevant technical parameters of coal seam slotting. It is believed that the model can be used to design the high-pressure water jet slotting pressure relief parameters in deep rock burst coal seams.

Numerical investigation of flow resistance in cone-straight nozzle

High-pressure water jet technology is applied to wellbore cleaning, descaling, auxiliary rock breaking, slit penetration, etc. In petroleum engineering. The cone-straight nozzle structure is widely used in the petroleum industry, and its internal flow resistance remains unclear, which plays an important role in nozzle geometry optimization and is the main research content in this paper. Large Eddy Simulations were used to simulate the near-wall flow field at a relatively low Reynolds number, the flow resistance is analyzed based on the numerical calculation data, and the following conclusions are drawn: The friction resistance is mainly distributed at the end of the converging section and the throat section, and there is a peak value, and the viscous force is mainly distributed in the converging section; the streamline structure can effectively reduce the skin friction resistance, and has little effect on the viscous force, which is more sensitive to the length of the nozzle; the streamline structure can change the trend of the total pressure in the nozzle, but has little effect on the kinetic energy conversion efficiency of the entire nozzle; increasing the fluid viscosity significantly increases the flow resistance in the nozzle. The purpose is to reveal the flow resistance inside the nozzle, investigate the factors affecting the flow resistance and provide theoretical support for the optimization of the nozzle structure.

Micro-nano twins appearing in ultrafine-grained Ti–6Al–4 V alloy induced by high-pressure water jet technology

In this study, the surface of an ultrafine-grained Ti–6Al–4 V alloy was treated with high-pressure water jet technology (HPWJT). Then, the microstructure of the alloy was investigated using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). Three obviously different microstructural characteristics were observed from the treated surface to the matrix: ultrafine equiaxed grains with diameters from hundreds of nanometers to a few micrometers, micro-nano twins inside ultrafine equiaxed α grains, and an initial undeformed microstructure with ultrafine equiaxed grains. Formation of micro-nano twins in the subsurface was related to the special misorientation angle of neighboring grains. We proved the dependence of twinning on the crystallographic orientation and grain size of the α phase. In addition, the quantitative contributions of the micro-nano twins to the surface hardness of the alloy were calculated; micro-nano twins significantly improved the surface hardness of the alloy. This study provides a new easy method for introducing micro-nano twins on the surfaces of Ti and its alloys, and it may further improve the mechanical properties of these alloys.

Optimization Design and Analysis of Bionic Friction Reducing Nozzle in Oil Shale High-Pressure Jet Mining

The borehole hydraulic mining method has unique advantages for underground oil shale exploitation. Breaking rock with a high-pressure water jet is a crucial step to ensure the smooth implementation of borehole hydraulic mining in oil shale. The hydraulic performance of the nozzle determines the efficiency and quality of high-pressure water jet technology. To obtain a superior hydraulic performance nozzle, based on the bionic non-smooth theory, a circular groove was selected as the bionic unit to design a bionic straight cone nozzle. The structural parameters of the circular groove include the groove depth, width, and slot pitch. The optimization objective was to minimize the pressure drop, where the fluid has the least resistance. A genetic algorithm was used to optimize the structural parameters of the circular grooves in the inlet and outlet sections of the bionic straight cone nozzle. The optimal structural parameters of the nozzle were as follows: the inlet diameter was 15 mm, the inlet length was 20 mm, the outlet diameter was 4 mm, the length-to-diameter ratio was 3, and the contraction angle was 30°. In addition, in the inlet section, the groove width, slot pitch, and groove depth were 3.9 mm, 5.2 mm, and 5.5 mm, respectively, and the number of circular grooves was 2. Moreover, in the outlet section, the groove width, slot pitch, and groove depth were 2.25 mm, 3 mm, and 5.5 mm, respectively, and the number of circular grooves was 2. The CFD numerical simulation results showed that under the same numerical simulation conditions, compared with the conventional straight cone nozzle, the bionic straight cone nozzle velocity increase rate could reach 13.45%. The research results can provide scientific and valuable references for borehole hydraulic mining of high-pressure water jets in oil shale drilling.

Formation Principle and Characteristics of Self-Supercharging Pulsed Water Jet

High-pressure pulsed water jet technology has considerable development potential in the field of rock fragmentation. To overcome the shortcomings of existing pulsed jets, a self-supercharging pulsed water jet (SSPWJ) generation method is proposed, which is based on the theory of the pulsed water jet and the principle of hydraulic boosting. The proposed method changes the flow direction of the fluid medium through the valve core to make the piston reciprocate in the cylinder and relies on the effective area difference between the front and rear chambers in the stroke stage of the piston to realize the organic combination of “pulse” and “supercharging” of the jet, thus forming an SSPWJ. On the basis of the formation principle of the SSPWJ, a SSPWJ testing platform was constructed, and tests were performed on the jet pressure acquisition, morphology capture, and granite erosion. Both the jet pressure and the jet morphology exhibited periodic changes, and a higher pulse pressure was obtained at lower inlet pressure. The error of the pressure ratio calculated according to the experimental results was <3% relative to the theoretical design value, confirming the feasibility of the method. The pulse pressure and pulse frequency are controllable; that is, as the inlet flow rate increases in the stroke stage of the piston, the pulse pressure and pulse frequency increase, and the pulse duration decreases. As the inlet flow rate increases in the backward-stroke stage of the piston, the pulse frequency increases, and the pulse pressure and pulse duration remain unchanged. Under the combined action of the water-hammer pressure, high-speed lateral flow, and high-frequency dynamic load of the SSPWJ, local flaky exfoliation was observed when the granite surface was eroded. The results of this study lay the foundation for enriching the theory of pulsed jet generation and expanding its application range.

The mechanism and application of high-pressure water jet technology to prevent compound dynamic disaster

The mechanism and application of high-pressure water jet technology to prevent compound dynamic disaster

Application of High Pressure Water Jet Technology in Cleaning Polymerization Vessel

In recent years, the demand for organic synthetic materials in chemical production process is increasing, in order to meet the growing demand for organic synthetic materials in various fields. As the core equipment, the efficient and orderly operation of polymerizer is very important to ensure safe production and improve production efficiency. Under normal working conditions, the deposition or adhesion of polymer plasticizers will inevitably occur as long as there are monomer contacts in the polymerization reaction of any process, and the adhesion of polymer products to the wall of the reactor will cause sticking problems, so regular cleaning of the reactor has become a necessary link. High-pressure water jet cleaning technology is a new type of cleaning technology emerging in the world in recent years. It has the advantages of low cost, high speed, high cleaning rate, no damage to the cleaned products, no pollution, etc. In this paper, the concept of cleaning polymerizer with high pressure water jet technology is briefly introduced. Through the study of the mechanism of the autoclave and the analysis of the characteristics of the autoclave, the cleaning of polymerizer with high pressure water jet technology is discussed.

Research on the Influence of External Parameters of Fan-Type Nozzle on Water Jet Performance

At present, high-pressure water jet technology occupies a very important position in the automobile washing industry. Some automatic washers cannot meet the washing requirements in the washing process due to unreasonable arrangement of nozzles on their spray rods. Based on the theory of computational fluid dynamics (CFD), the internal and external flow field model of the nozzle are established in this paper. Fluent is used to simulate and analyze the flow field, and the external parameters of the nozzle on the side spray bar of the automatic automobile washer are optimized. The simulation results show that after the nozzle and the normal line of the automobile surface are inclined at a certain angle, the target surface is affected not only by normal striking force but also by tangential pushing force, which makes stains easier to remove. The washing effect is the best when the nozzle is inclined 30° to the normal line of the automobile surface. Increasing the nozzle inlet pressure will increase the dynamic pressure on the automobile surface, but the increase of dynamic pressure will decrease after increasing to a certain pressure. The inlet pressure has little effect on the area covered by water jet. The reasonable matching results of jet angle, nozzle spacing, and nozzle distance from the automobile surface (target distance) obtained by numerical simulation can not only make the automobile surface completely covered and cleaned but also ensure less jet interference and no waste of water from adjacent nozzles. The above research conclusions can provide a basic theoretical basis for the optimal design of automatic automobile washing.

Review of Underwater Ship Hull Cleaning Technologies

This paper presents a comprehensive review and analysis of ship hull cleaning technologies. Various cleaning methods and devices applied to dry-dock cleaning and underwater cleaning are introduced in detail, including rotary brushes, high-pressure and cavitation water jet technology, ultrasonic technology, and laser cleaning technology. The application of underwater robot technology in ship cleaning not only frees divers from engaging in heavy work but also creates safe and efficient industrial products. Damage to the underlying coating of the ship caused by the underwater cleaning operation can be minimized by optimizing the working process of the underwater cleaning robot. With regard to the adhesion technology mainly used in underwater robots, an overview of recent developments in permanent magnet and electromagnetic adhesion, negative pressure force adhesion, thrust force adhesion, and biologically inspired adhesion is provided. Through the analysis and comparison of current underwater robot products, this paper predicts that major changes in the application of artificial intelligence and multirobot cooperation, as well as optimization and combination of various technologies in underwater cleaning robots, could be expected to further lead to breakthroughs in developing next-generation robots for underwater cleaning.

Influence of Processing Parameters on Coating Removal for High Pressure Water Jet Technology Based on Wall-Climbing Robot

The shipbuilding industry is very important for many countries. As an essential process in the shipbuilding industry, surface preparation (or coating removal) is gaining more and more attention. The traditional process used for ship hull coating removal is a sand-blasting process, which is harmful to the environment and inefficient. Recently, high pressure water jet technology has been developed to replace the traditional sand-blasting process. However, there are still many technical problems to be solved. In this paper, one wall-climbing robot was developed to remove coating based on high pressure water jet technology. Coating removal experiments under various experimental conditions were carried out and the corresponding coating removal rate for each case was obtained and compared. In addition, numerical simulation based on Fluid software was conducted to observe the water jet process more visually. Results show that the processing parameters, including the water pressure, travelling speed, inclined angle, and stand-off distance, can greatly influence the coating removal effect. The optimal processing parameters are obtained to guide the application of the high pressure water jet technology based on the designed wall-climbing robot for the shipbuilding industry.

Bionic optimum design of straight cone nozzle and the effectiveness evaluation of reducing fluid resistance

High-pressure water jet technology is a clean and effective approach to break, cut or clean solid materials. The nozzle’s hydraulic performance determines the efficiency and quality of the high-pressure water jet technology implementation. The fluid resistance reduction technology of bionic non-smooth surface is applied to the structural design of the straight cone nozzle successfully. The circular groove is selected as the bionic unit. The selection results in the investigation and development of a bionic straight cone nozzle with the optimum hydraulic performance. Moreover, the separated nozzle machining method is successfully implemented. A comprehensive approach that implements the orthogonal experiment, high-pressure water jets’ impact forces testing and range analysis results in the optimization of the bionic straight cone nozzle’s structure. The optimal structural parameters of the nozzle as follows: the outlet diameter is 4 mm, length-to-diameter ratio is 2.5, contraction angle is 60°, the circular groove width is 3 mm, the circular groove depth is 2 mm and the circular groove number is 2. In addition, the circular grooves are uniformly arranged on the surface of the straight cone nozzle’s internal chamber resulting in reduction of the fluid resistance effectively. Under the same experimental conditions, the impact forces of high-pressure water jets produced by the bionic straight cone nozzles are greater in comparison with the impact forces of high-pressure water jets produced by the ordinary straight cone nozzles. The average rate of fluid resistance reduction of bionic straight cone nozzles is up to 2.33%. Furthermore, the results of CFD numerical simulation show that the circular grooves at the contraction and the outlet sections can also reduce the high-pressure water flow resistance effectively. In the meantime, the opposite rotating vortexes in the circular grooves are the main reason for the reduction in fluid resistance of the bionic straight cone nozzle.

Finite element analysis of nozzle selection based on high pressure water jet technology

High-pressure water jet technology is an emerging type of welding joint strengthening process in recent years, which has unique advantages such as non-polluting, high efficiency, and can strengthen some complicated welds that in dead end position such as fillet welds. However, there is no supporting water jet strengthening nozzle domestically, so this paper uses the computational fluid dynamics method to simulate the internal and external flow fields of the nozzle, which is the most commonly used four conical convergence nozzles with different structure of the current water jet technology, making the flow field velocity distribution of the four nozzles and the impact pressure on the target surface compared and analysed. The results show that the impact pressure and axial speed of the conical short-line nozzle are slightly smaller than that of the conical (13°) nozzle, but conical short-line nozzle’s jet collection property and stability are superior to the other types of nozzles. Therefore, the conical short-line nozzle should be selected when the high-pressure water jet technology is utilized for welding joint reinforcement.

Study on parameters optimization of coalbed gas drilling drainage by high pressure water jet

Coalbed gas is a kind of non-conventional energy with non-pollution and high-quality. High pressure water jet technology has many advantages in coalbed gas drilling drainage, due to no heat effect, high flexibility, and high surface quality. To reduce the energy consumption of this technology, especially for the hard coal rock, the water jet parameters optimization is studied in this paper. Based on an established three-dimensional damage numerical model and the orthogonal design tests, it analyzes the influence characteristic of different water jet parameters on coal bed gas drilling drainage and obtains the optimal water jet parameters combination finally. The results could improve the efficiency of high pressure water jet drilling drainage.

Shale rock fragmentation behaviors and their mechanics by high pressure waterjet impinging

High pressure waterjet technology is a potentially advanced technology to improve the drilling efficiency of shale rock formation. The success of waterjet drilling requires more insight into the rock fragmentation behaviors and their mechanics. In the present study, a series of submerged waterjet impinging trials were carried out on the outcrop shale rock collected from the Longmaxi Formation, Sichuan Basin, China. Simultaneously, the sandstone was selected as the candidate of the control group. The macro fragmentation behaviors and their micro structures were acquired by the scanning electron microscope (SEM) and computed tomography (CT) techniques. The rock mechanics and mineral composition before and after experiments were measured by the standard ISRM method and X-ray diffraction, respectively. Particularly, the grain size distributions of cuttings were obtained by a laser particle size analyzer. Results show that the efficiency of shale waterjet drilling is ultralow, which the rate of penetration and the ultimate drilling depth cannot reach the half of those sandstone. SEM imaging shows that shale is ultra-tight in which the illite clay weaves into a network and the dolomite embeds into the network. It just likes a concrete material resulting in the high compression strength. Since the static pressure of waterjet is lower than the compression strength, the common compression-shear failure does not happen, but only the tensile fracture occurs and makes the rock spallation for the initial crushing. With the penetration depth increasing, the waterjet impinging force is not able to make the rock tensile or shear failure. Only the particle erosion becomes a dominant failure mechanism for shale rock where the mineral particles are removed or crushed from rock matrix as fine cuttings. This work provides the theoretical guide for improving the shale rock drilling efficiency by water jetting.