Ultra-high Pressure Water Research Articles

Damage and fracture characteristics of thermal-treated granite subjected to ultra-high pressure jet

The water jet rock breaking technology has broad application prospects in geoenergy development engineering. However, the influence of reservoir temperature on the rock breaking effect is still unclear during the jet rock breaking process. To explore the mechanism of temperature on rock breaking by high-pressure water jets, experiments on the erosion of high-temperature granite by ultra-high pressure pure water jets (UHP-PWJ) and ultra-high pressure abrasive water jet (UHP-AWJ) were conducted at five rock temperatures: 25 °C, 100 °C, 200 °C, 300 °C, and 400 °C. Through three-dimensional reconstruction and microscopic observation techniques, the macroscopic and microscopic characteristics of rock fragmentation were analyzed, ultimately revealing the dynamic damage and rock breaking mechanisms of ultra-high pressure water jet. The results indicated that rock temperature influences result in different fragmentation characteristics under the action of two types of jets, with UHP-PWJ demonstrating significantly superior rock-breaking effects on high-temperature granite compared to UHP-AWJ. As granite temperature increases from 25 °C to 400 °C, the damage depth range for the UHP-PWJ is 30–75 times the nozzle diameter, while for the UHP-AWJ, it is only 30–40 times the nozzle diameter. For UHP-PWJ, the rock breaking mechanism is mainly driven by thermal stress, supplemented by high-speed jet impact. The significant increase in rock temperature significantly enhances its rock breaking effect, with erosion pits appearing in a spindle shape and more complex crack distribution around the pores. Compared with 25 °C granite, the damage caused by 400 °C granite jet impact increased by 6.8 times and the surface area of cracks increased by 6.5 times. For UHP-AWJ, high temperature hard rock fragmentation still relies mainly on jet impact and abrasive grinding. The thermal stress caused by rock temperature has a relatively small impact on its rock breaking effect, and the D value of the internal damage degree of granite at different temperatures is less than 0.005. The erosion pits are conical in shape, and no macroscopic cracks caused by jet impact and thermal cracking can be clearly observed around the pit. The research results can provide a theoretical basis for optimizing the parameters of high-pressure jet development technology for deep geoenergy.

Experimental study on surface erosion of Grade-A marine steel with different curvatures by ultra-high pressure water jet

To investigate the erosion mechanism and model of ultra-high pressure (200 MPa) water jet on grade–A marine steel with different curvatures. The ultra-high pressure water jet was induced by plunger pump. The dynamic strain was collected by dynamic strain gauge during impact to explore the mechanical effect. The microstructure was analyzed using three-dimensional topography and a scanning electron microscope. The results show that the average microstrains of samples with the curvature of 1/4 m−1, 3/4 m−1, and 5/4 m−1 impacted by ultra-high pressure water jet are 707, 952 and 1053, respectively, and the strain amplitudes are 300∼700, 300–600 and 300–560 respectively. The force exerted on the surface of the curved samples manifested as cyclic, pulsating, and alternating stress. With the curvature increase, the roughness decreases by 19.22%, 48.64%, and 21.31%, respectively. Meanwhile, surface damage, material removal, pits, holes, and cracks decrease. Finally, the erosion mechanism is clarified, and the erosion model of the ultra-high pressure water jet on grade–A marine steel with different curvatures is established.}

Analysis of Influence of Ultra-High Pressure Water Jet Cutting Pressure Sequence on Pressure Relief and Reflection Improvement of Coal Seam

In order to explore the pressure relief effect of the two combined pressure relief and antireflection technologies of ultra-high pressure water jet cutting before pressure and pressure before cutting, theoretical analysis, numerical simulation, and field test were used to study the main control factors of the combined high-pressure water jet slit cutting and fracturing antireflection technology. This paper introduces the combined technology of ultra-high pressure hydraulic fracturing, and analyses the mechanism of pressure relief and transparency enhancement of the combination of cutting before pressure and pressure relief after cutting. The results show that the starting pressure of the coal seam with ultra-high pressure water jet cutting and pressure relief is 13 MPa, the influence radius of hydraulic fracturing is 45–55 m, the starting pressure of the coal seam with pressure cutting and pressure relief is 16 MPa, and the influence radius of hydraulic fracturing is 35–45 m. Compared with pressure cutting combined pressure relief and permeability enhancement technology, cutting pressure relief and permeability enhancement technology can improve the permeability of coal seams more evenly and effectively, and reduce the stress of coal seams near the hole. The ultra-high pressure cutting and pressure combined technology can make the pressure relief of coal body uniform and sufficient, and the overall permeability coefficient of the coal body is greatly improved. The drilling purity is 2.3 times of the extraction purity of the ordinary single hole drilling, and the extraction influence range is increased, and the extraction effect is significantly improved. At the same time, the stress of coal body is reduced after slitting, and the starting pressure of hydraulic fracturing is reduced. The research results provide a scientific basis for the coal seam pressure relief and permeability enhancement under similar conditions in the mining area and have a broad application prospect.

Effect of technological parameters on hydrodynamic performance of ultra-high-pressure water-jet nozzle

With the increasing requirement for environmental protection in the area of ship rust removal, ultra-high-pressure (UHP) water-jet technique attaches much attention. Because derusting nozzle is one of the key parts to determine the efficiency of a UHP rust removal system, a better understanding of its technological parameters is required. According to the operation characters associated with UHP water-jet derusting nozzle, the 3D simulations are performed to investigate the nozzle's hydrodynamic performance, taking the cavitation effect, multiphase flow and liquid compressibility models into account. Subsequently, according to the rule of the Latin hypercube sampling (LHS) method, 400 datasets are determined. Pearson correlation, Kendall correlation and Spearman correlation coefficients are selected to analyze the database of UHP water-jet nozzle. It is found that the standoff distance (SOD) and jet angle have the most dominant effect on the magnitude of wall shear stress. Finally, the influence of different SODs and jet angles on hydrodynamic performance of UHP water jet is analyzed by regarding the distribution trends of wall pressure and wall shear stress on target surface as critical contrastive indicators. The distribution rules of the peak wall pressure and wall shear stress on target surface which are attributed to the variation of SODs and jet angles are summarized, and the optimum combination of these two key technological parameters is proposed. This related research provides a reference for the determination of technological parameters.

Experimental Study on Surface Erosion of Grade A Marine Steel by Ultrahigh-Pressure Water Jet

To investigate the interaction and erosion mechanisms between an ultrahigh-pressure water jet and the surface of Grade A marine steel, this study used the ANSYS FLUENT software to simulate the hydrodynamic characteristics of an ultrahigh-pressure water jet. To erode the Grade A marine steel, a water jet with ultrahigh-pressure (200 MPa, 40 L/min) was used. An ASMC2-4 resistance strain gauge collected the dynamic strain signal at the back of the sample during jet impingement, and the simulation results were compared to experimental results. A scanning electron microscope (SEM), X-ray diffractometer (XRD), energy dispersive spectrometer (EDS), and other equipment were used to observe and analyze the phase before impact and the material surface morphology and element distribution after impact. The results reveal that as the wall shear stress increased with the target distance, the energy loss of the jet could be reduced by changing the jet incidence angle, and the peak value of the wall shear stress increased. Under the pressure of 200 MPa, the average microstrain at the back side of the impact center area of the Grade A marine steel was 180 × 10−6, and the microstrain amplitude was 35 × 10−6–50 × 10−6. The impact force of the water jet on the Grade A marine steel produced alternating stress with cyclic fluctuation. The experimental results are consistent with the simulation results. Under the alternating jet stress action, fatigue failure and cavitation failure occurred on the sample surface, which was characterized by a spalling pit, layer erosion, and cavitation hole morphology. The surface stripping model of the Grade A marine steel under an ultrahigh-pressure water jet was established, and the interaction mechanism and erosion mechanism between the ultrahigh-pressure water jet and the surface of the Grade A marine steel were elucidated.

Pressure Drop Model and Jet Features of Ultra High Pressure Water Jet for Downhole Intensifier

Abstract Existing models can hardly provide a reliable guidance in designing intensifier utilizing axial vibration energy of drill strings. The formation process of jet and the pulsation characteristics of flow field had not been reported. Therefore, a new model combined plunger movement and nozzle pressure drop is proposed. The jet formation process, characteristic of water jet distribution, pressurization performance, and impinging pressure under different parameters were studied based on a computational fluid dynamics (CFD) method. The results show that there is a good agreement between the model and the CFD. Increasing the plunger diameter can prolong the holding time of the high-pressure water jet and increase the peak pressure, but it does not affect the pressurization period, which is mainly influenced by the spring. There are three representative stages observed in the forming process of high-pressure water jet, and in stable potential core stage, the inlet pressure does not affect the length of potential core, which is about seven times the nozzle diameter. The impinging pressure decreases with the radial distance, the maximum of which is at the center of the jet. The stand-off distance should be less than 7d, otherwise the impinging pressure will decrease sharply. The research can provide a reference for the optimal design of intensifier and will be beneficial for downhole pressurized jet-assisted drilling techniques.

Investigation on pore structure, fluid mobility and water huff-n-puff oil recovery of tight volcanic oil reservoir

The pore structure of tight volcanic oil reservoirs is very complex and the permeability is extremely low. The oil recovery effect of traditional water-driven and gas-driven development is not ideal. In this paper, we first analyzed the pore structure characteristics and fluid movability characteristics of tight volcanic rocks. Then, the feasibility of water huff-n-puff in tight volcanic rocks was analyzed. Finally, we investigated the oil recovery characteristics, pore motility characteristics, and ORM of water huff-n-puff in tight volcanic rocks by using a high temperature and ultra-high pressure water huff-n-puff physical simulation experimental device under NMR monitoring. The study shows that the mineral composition of tight volcanic rocks is relatively simple, but the pore structure is very complex. The pores are mainly amygdule pores, and contain some vesicular pores and matrix pores. The fractures include structural fractures, dissolution fractures, and shrinkage fractures. Fractures are of great significance for communicating relatively independent pores and improving the seepage ability of fluids in tight volcanic rocks. The fluid movable saturation of tight volcanic rocks is 32.93%–83.75%, and the minimum movable pore radius is 0.0178 μm. The seepage capacity of large pores (r > 0.1 μm) is 2.19–7.75 times that of middle pores (0.001 μm < r < 0.1 μm). The oil recovery efficiency (the ratio of the volume of recovered oil to the volume of injected water) of the first two cycles of water huff-n-puff of tight volcanic rocks exceeds 20%, which is high-efficiency oil recovery period. However, with the increasing huff and puff cycles, the recovery factor and oil change rate both decrease rapidly. After five cycles of water huff-n-puff, the recovery factor of tight volcanic rocks increases by 29.13%. For the selected experimental core, middle pores are the main oil-producing pores, and their contribution rates in natural energy depletion and five cycles of water huff-n-puff are 59.665% and 78.173%. In five cycles of water huff-n-puff, the contribution rates of elastic displacement are 96.491%, 93.846%, 86.667%, 64.706%, and 55.556%, and the effect of imbibition displacement is relatively small. Increasing the water injection pressure is beneficial to water huff-n-puff oil recovery of tight volcanic rocks. The research can provide a good theoretical basis for the efficient development of tight volcanic oil reservoirs.

An experimental study of ultra-high pressure water jet-induced fracture mechanisms and pore size evolution in reservoir rocks

Ultra-high pressure water jets (UHP-WJ) rock breaking is a promising technology for developing unconventional natural gas reserves . In this study, rock-breaking experiments were conducted using typical reservoir rock samples such as sandstone , shale, and coal. The failure patterns in rocks after impact by UHP-WJ were analyzed. Moreover, the 3D damage field model of the rock was reconstructed based on CT scanning, and the internal crack distribution was visualized and examined. Furthermore, the fracture mechanisms of three types of reservoir rocks under the UHP-WJ impingement were studied. The results indicate that intergranular fractures produced due to shear stress are the dominant type of fracture in sandstones, tensile failure due to stress wave was the main type of fracture observed in shale, and coal exhibited the double breaking characteristics of stress wave effect and water wedge effect. The fragments size distribution of samples shows the largest fragments in shale, followed by coal, and the smallest fragments are observed in sandstone. Finally, the evolution of rock pore structure before and after the impact of UHP-WJ was monitored by nuclear magnetic resonance (NMR) methods. The results reveal that the micropores transform into mesopores and macropores in the sandstone, where the total porosity increased by 14.3%–24.8%. As the jet pressure exceeds 100 MPa, the porosity of shale increases significantly, such that the total porosity of the shale sample increased by 7.6%–37.1%. The mesopores transform into macropores and fractures with the influence of the water wedge effect in coal samples, resulting in the reduction of mesopores and the increase of macropores, where the total porosity of the coal sample increased by 14.6%–40%. The complexity and heterogeneity of pores were reduced under UHP-WJ with the increasing jet pressure. The findings provide a theoretical reference for optimizing the recovery from unconventional natural gas reservoirs .

ROBBE – Robot-aided processing of assemblies during the dismantling of nuclear power plants

For a successful decommissioning and dismantling of an NPP (Nuclear Power Plant), correct and controlled processing of all components is necessary, whereby a large part of the work relates to coated (mainly painted) steel components, which make up a significant proportion of the total inventory of the power plant to be processed. The contamination of these components is reduced by removing the surface coating using UHP (Ultra-High-Pressure) water jet blasting technology. Thus, the decontaminated material is released to be recycled conventionally after receiving clearance in accordance with Chap. 3 StrlSchV (German Federal Law Gazette 2018 No. 41: StrlSchV, 2018). The manual processing of these individual parts is cost-intensive, so that an autonomous, automated solution is more economical while increasing throughput at repeatable high quality. ROBBE aims at implementing a robot-assisted, automated and autonomous decoating procedure of component groups using UHP water jet blasting technology and implements it ata German NPP in Biblis on an industrial, productive scale.

Dynamic failure analysis of static seals under pressure fluctuation in an ultrahigh-pressure water piston pump

For ultrahigh-pressure piston pumps, in the reciprocating action of the piston, the fretting between the static face seal and the mating surface occurs with the change of the pressure in the piston chamber. This phenomenon will seriously affect the service life of the seal ring and lead to the failure of the pump. However, the failure of static seals used to seal ultrahigh-pressures is usually studied from the directions of shear, stress, or rubber material. These studies cannot explain the failure phenomenon of the sealing ring found in our experiment. This paper analyzed the failure of the face seal ring in a piston pump with a maximum pressure of 120 MPa. A two-dimensional axisymmetric finite element model was established based on the Mooney-Rivlin constitutive relation of the rubber material, and the fretting conditions of the sealing ring were analyzed. Combined with the wear scars observed by the scanning electron microscope the face seal ring’s dynamic failure mechanism on the ultrahigh-pressure piston pump was determined. A better sealing scheme was proposed and verified by the duration test of the pump, which provided a basis for the design of the sealing of the ultrahigh-pressure fluid with high-frequency fluctuations.

Research and field application of ultra high pressure hydraulic cutting technology in Gaohe coal minethe title of your paper here

In order to improve the permeability of low permeability coal seam, improve the gas drainage efficiency of + 450m bedding boreholes in Gaohe mine, and ensure the safe and rapid excavation of + 450m level north wing air inlet roadway, ZGF-100 (a) type ultra-high pressure hydraulic slotting device suitable for the characteristics of 3 coal seam in Gaohe mine is developed. The feasibility and implementation scheme of high pressure water drilling and slotting integration technology are studied, and the slotting effect is preliminarily analyzed investigate. The research shows that the technology of using ultra-high pressure water to cut coal seam to cause cracks and increase permeability can effectively conduct the original cracks in the coal body, increase the gas drainage effect of boreholes along the seam, increase the drainage pure quantity by 1.8 ∼ 3.6 times, increase the effective drainage radius from 1.3m to 2.4m, and reduce the drilling engineering quantity by more than 50%. Hydraulic cutting technology can effectively improve the gas drainage efficiency of low permeability coal seam, which is worthy of promotion.

Method for selecting and substantiating the parameters of machines for water jet grouting of unstable seasonally frozen soil masses

The paper presents a method for selecting and substantiating the parameters of machines for water jet grouting (WJG) of unstable seasonally frozen soil masses. This method makes it possible to determine the main parameters of WJG machines that ensure the implementation of process tasks with rational process parameters. The method is based on the use of patterns established as a result of experimental studies, reflecting the relations between WJG parameters. It allows us to determine the set of values of the most significant parameters characterizing the use of a given type of equipment in a specific case of their combination. In this case, a range of values of the main equipment parameter is determined, which makes it possible to set the operating characteristics of the WJG process, on the one hand, and form the basis for generating a parametric series and a dimension range of equipment, on the other hand. The paper presents examples of the practical use of the proposed method when designing rotary couplings and units for WJG or developing high and ultra-high pressure water sources for machines used for water jet breaking of rocks.

Study on the mechanism of breaking concrete by ultra-high pressure water jet

The concrete breaking mechanism of ultra-high pressure water jet is divided into two parts: the characteristics of ultra-high pressure water jet and the characteristics of concrete under the action of water jet. Through the analysis of the water wedge and water hammer under the action of the jet on the concrete breaking, ultra-high pressure water jet pressure and jet on the concrete strike force is a linear relationship.

Optimization of technological parameters of water jet cutting of red oak and bamboo based on three-dimensional surface topography measurement

In order to accurately and reliably optimize the process parameters of ultra-high pressure water jet cutting for wood, water jet processing was conducted on red oak and bamboo floor specimens, and the materials were scanned for three-dimensional surface topography. The surface roughness value of the cut surface of the test piece was measured by the orthogonal measurement method as an evaluation index to determine the optimal arrangement of the influencing factors and the process parameters. Finally, the water cutting mechanism and three-dimensional shape of the processed test piece were analyzed. The factors affecting were as follows: cutting pressure &gt; feeding speed &gt; abrasive flow rate &gt; target distance &gt; air-dry density. The optimal experimental scheme included an abrasive flow rate of 35 kg/h, cutting pressure of 310 kPa, feed speed of 250 mm/s, target distance of 3 mm, and air dry density of 620 kg/m3. Under these processing conditions, the surface roughness values of water jet red oak and bamboo specimens were relatively small, and the processing quality was the best. The results of the above-mentioned research can provide a reference for the research and application optimization design of wood and bamboo processing for ultra-high pressure water jet technology.

Research on Multi-level Protection Technology Based on ZGF-100(A) Ultra-high Pressure Hydraulic Drilling and Cutting Integrated Device

In order to ensure the safety of hydraulic transmission and slitting operation under ultra-high pressure, the composition of ZGF-100(A) ultra-high pressure hydraulic drilling and cutting integrated device, the main technical parameters of the complete set and the main technical indexes are described. ZGF-100 Based on the (A) type of ultra-high pressure hydraulic drilling and cutting integrated device, it is protected from the protection of ultra-high pressure water source, the protection of ultra-high pressure water transmission channel, the connection protection of key components of ultra-high pressure hydraulic transmission and the specification of ultra-high pressure hydraulic cutting operation. Ultra-high pressure hydraulic slitting multi-stage protection technology was studied. The equipment safety laboratory experiment was carried out. Under the experimental conditions of test pressure 120 MPa and pressure retention for 30 min, there was no leakage between the slash shallow spiral integral drill pipe, the ultra-high pressure rotary water tail and the ultra-high pressure hydraulic hose. The ground test of safety performance of complete sets of equipment was carried out. Under the conditions of experimental pressure of 100 MPa and duration of 30 min, no leakage occurred in all parts of the ultra-high pressure pipeline system, which was safe and reliable. After adopting the multi-stage hydraulic secant multi-level protection technology, the safety of the complete set of equipment is effectively improved, the safety of the ultra-high pressure hydraulic slitting operation can be effectively ensured, the occurrence of the accident of the ultra-high pressure water injury is prevented, and the operator’s personal life is guaranteed. Safety reflects good social benefits.

Design of hull ultra high-pressure water ejector derusting system

In this text, the system takes the hull of the 82000 DWT bulk carrier as the research object, this system analyses the common methods and existing shortcomings or problems of the existing hull rust removal methods. In view of the shortcomings or problems of these methods, the design requirements of the hull rust removal system are set out. Based on AutoCAD design platform, a high-pressure water jet rust removal system is designed, its working principle and main components are introduced, and the main parts of the system are selected for calculation.

Modelling and multi-objective optimization of surface roughness and kerf taper angle in abrasive water jet machining of steel

Abrasive water jet machining (AWJM) is a popular method used for cutting purposes. It uses a thin jet of ultra-high pressure water and abrasive slurry to cut the material and the cutting is mainly by erosion. The purpose of this paper is to investigate the effect of AWJM parameters on the cutting of mild steel and to optimize the process parameters. The process parameters considered for investigation are traverse speed, abrasive flow rate and standoff distance. The subsequent response parameters that have been determined are surface roughness and kerf taper angle. Taguchi L9 orthogonal array has been used to design the experiments. ANOVA is used to decide the influencing process parameters. 3D surface plots are presented for interaction effects of input process parameters. The study revealed that traverse speed is the prime factor influencing surface roughness and kerf taper angle followed by stand-off distance and abrasive flow rate. Response models are verified on the basis of estimation capability. Later on, multi-objective optimization using response surface methodology has been used for minimizing surface roughness and kerf taper angle which further resulted in composite desirability of 0.9497. The optimum values of abrasive flow rate, standoff distance and traverse speed are found to be 420 g/min, 3 mm and 85 mm/min, respectively. To validate the results, confirmation test is performed using optimum cutting parameters. It showed 9.17 and 8.57% error for surface roughness and kerf taper angle.

Recycling waste tire rubber by water jet pulverization: powder characteristics and reinforcing performance in natural rubber composites

Abstract Pulverization is a general strategy used prior to any practical application of recycled waste tire rubber (WTR). Mechanical grinding, in use currently, is an inefficient technique due to low-quality rubber powder production and certain indispensable additional pretreatments. The aim of this study is to propose a novel pulverization technique of WTR by ultrahigh pressure water jet. Efficient pulverization of WTR was accomplished by water jet without any pretreatment. Powder characteristics, including particle size distribution (PSD), surface area, thermal behavior and chemical structure changes, were investigated. The curing, mechanical and morphological properties of natural rubber (NR) vulcanizates filled with ground tire rubber (GTR) from water jet pulverization (WJPULV) were evaluated. The results indicate that GTR granules from WJPULV possess a quite fine PSD and large surface area, show similar thermal degradation behaviors to the original WTR and have been partially devulcanized. The improvement of tensile and tear strength of the composites reveals that GTR from WJPULV can be added up to 40 phr without adverse effect. The morphological analysis corroborates the homogeneity of GTR in the NR matrix. All findings confirm that water jet can be an excellent choice for pulverization of WTR.

Application of pre-alloyed powders for diamond tools by ultrahigh pressure water atomization

Copper, iron and cobalt based pre-alloyed powders for diamond tools were prepared by ultrahigh pressure water atomization (UPWA) process. Pre-alloyed powders prepared by different processes including UPWA, conventional water atomization (CWA) and elemental metal mechanical mixing (EMMM) were sintered to segments and then compared in mechanical properties, holding force between matrix and diamond, fracture morphology of blank and sintering diamond section containing matrix. The results showed that the pre-alloyed powder prepared by UPWA exhibits the best mechanical properties including the relative density, the hardness and the bending strength of matrix sintered segment. Sintered segments fractography of UPWA pre-alloyed powder indicates mechanical mosaic strength and chemical bonding force between the pre-alloyed powder and the diamond, leading to the great increase in the holding force between matrix and diamond. The mechanical performance and the service life of diamond tools were greatly improved by UPWA pre-alloyed powders.

Cavitation desulfurization in vulcanized rubber recycling under ultra-high pressure water jet

Abstract Ultra-high pressure water jet is proposed for recycling of vulcanized waste rubber, and cavitation desulfurization in the recycling process is analyzed. The chemical effects of mechanical shearing, pyrolysis, free radical oxidation, and supercritical oxidation produced by bubble collapse are considered the main causes of desulfurization. Scanning electron microscopy, Fourier transform infrared spectrometry, differential scanning calorimetry, nuclear magnetic resonance test, and X-ray photoelectron spectroscopy are used to determine the performance of rubber powder. Gel fraction of rubber powder is measured to analyze the effect of jet pressure on desulfurization. Results indicate that the vulcanized rubber could achieve partial desulfurization. The glass transition temperature of the rubber powder slightly increases after crushing. With the increase of jet pressure, the gel fraction of rubber powder initially decreases and then increases, as well as achieves a minimum value at the jet pressure of nearly 220 MPa, which is ideal for desulfurization.