Hydraulic Impact Research Articles

Analysis of lubrication and sealing performance on textured piston pair with multi-factor coupling

PurposeThis paper aims to study the lubrication and sealing performance on the textured piston pair under the cross action of the shape and structure parameters. This paper further carries out the optimization design of low energy consumption hydraulic impact piston pair.Design/methodology/approachBased on the characteristics of the ring gap seal piston pair, the flow field analysis model of the whole film gap is established for its periodic treatment. The friction power loss of the piston pair is defined as the evaluation index of the lubrication performance and the leakage power loss as the evaluation index of the sealing performance. The orthogonal test design and CFD software were used to analyze the lubrication and sealing performance of the textured piston pair.FindingsThe cross action of shape and structure factors has a great influence of the lubrication and sealing performance on the textured piston pair. Clearance and shape parameters have great influence on it, while seal length and depth diameter ratio have little influence. The sealing performance of conical textured piston pair is good, while the lubrication performance of square textured piston pair is good. The primary and secondary order of influence of shape and structure on energy consumption on piston pair is B (seal clearance) > C (texture shape) > D (area ratio) > A (seal length) > E (depth diameter ratio).Originality/valueBreaking the defect of local optimization design on traditional piston pair structure, then find the matching relationship of structural parameters on textured piston pair. Further improve the lubrication and sealing performance of the piston pair, and provide reference for the global optimization design of the low energy consumption hydraulic impact piston pair.

Hydraulic Impact Simulation of Energy Saving Solenoid Directional Valve

Hydraulic Impact Simulation of Energy Saving Solenoid Directional Valve

Dynamics of One-Way Hydraulic Impact System with Two Piston Stop Tools

Dynamics of One-Way Hydraulic Impact System with Two Piston Stop Tools

Design and Experimental Verification of Pressurized Cylinders in Hydraulic Rubber Hose Pressure Washers

Hydraulic rubber hoses are subject to great hydraulic impact during the actual working process, which causes a great potential safety hazard. Therefore, it is necessary to carry out pressure tests on hose assemblies to ensure its quality, so providing a high pressure for the hydraulic hose has become the key technology of this problem. Aiming at solving the problem of detection of pressure resistance in hydraulic rubber hose cleaning machines, this paper analyzed the pressurization mechanism of the hydraulic pressurized cylinder and proposed a method of continuous pressurization. This paper also theoretically analyzed the pressure expansion of the rubber hose, and the conclusion is that for the maximum hose capacity (hose size is Φ25 mm × 6 m), the volume of water required to provide water in the hose from 10 MPa to 100 MPa is 0.59 L. The pressurized cylinder was designed and checked theoretically and analyzed by the finite element method. It is concluded that the maximum stress of the pressurized cylinder is concentrated at the bottom of the high-pressure chamber, and the outlet hole at the bottom of the cylinder barrel of the high-pressure chamber is the weakest part of the pressurized cylinder. The performance of the supercharging cylinder is verified by experiments, which proves the feasibility, rapidity and stability of the supercharging cylinder.

Operation of Norwegian Hydropower Plants and Its Effect on Block Fall Events in Unlined Pressure Tunnels and Shafts

The main objective of this study is to investigate the effect of hydropower plant operation on the long-term stability of unlined pressure tunnels of hydropower plants in Norway. The authors analyzed the past production data of some hydropower plants to find out the number of starts/stops and the frequency and magnitude of load changes. The study demonstrates that an average of 200–400 start/stop events are occurring per turbine per year for the analyzed period, with an increasing trend. Currently, 150–200 large load changes per turbine smaller than 50 MW are occurring every year, and this is expected to increase by 30–45% between 2025 and 2040 for one of the studied power plants. Most importantly, the monitored pressure transients and pore pressure response in the rock mass during real-time operation at Roskrepp power plant are presented. A new method is proposed to calculate and quantify the hydraulic impact (HI) of pressure transients on rock joints and the effect of duration of shutdown/opening, which is found to be the most dominant parameter affecting the magnitude. The results show that faster shutdown sequences cause unnecessary stress in rock mass surrounding pressure tunnel. The hydraulic impact (HI) can be more than 10 times higher when the shutdown duration is reduced by 50 percent. The study recommends that duration of normal shutdowns/openings in hydropower plants should be slower so that hydraulic impacts on the rock joints are reduced and cyclic hydraulic fatigue is delayed, prolonging the lifetime of unlined pressure tunnels and shafts.

CALCULATION OF THE TRANSITION PROCESSES IN THE PRESSURIZED WATER PIPES AT THE START OF THE PUMP UNIT

The article deals with processes of transition conduit when the centrifugal pump start determination value and hydraulic impact. Proper selection of the parameters of the transition process in the regulation of the operation of the units at the pumping station increases the reliability of the entire system, except for the pump, prevents vibrations that occur in it. Vibration damage and erosion are prevented.Using the results and graphs, it is possible to choose the right electric motor for the pump unit depending on the required pressure and water supply. Technical and economic efficiency is achieved by choosing the right engine. The construction of the graphical characteristics of the pump, determined the magnitude of the hydraulic impact in the grapho-analytical method.

Optimization of drilling parameters using improved play-back methodology

Drilling is one of the expensive operations in oil and gas production. The cost of drilling exponentially increases with an increase in non-productive time (NPT). Extending the drill bit life, reducing the NPT (minimizing downhole complications, round trips or bit trips, circulation time, etc.), and the total expended specific energy would reduce drilling costs. It can be achieved by increasing the rate of penetration (ROP) and optimizing drilling efficiency. This paper presents a novel approach for optimum drilling parameters based on real-time optimization of drilling rates, drilling efficiency, and bit hydraulics. And this can be visually substantiated by the play-back methodology employed on an exploratory well. To determine the inefficient drilling zones for different lithology, drilling specific energy (DSE), mechanical specific energy (MSE) was estimated at all operating conditions. The result shows that utilization of optimal drilling parameters reduces input power by nearly 75%. Further, in this study, a new metric termed hydraulic drilling impact (HDI) is introduced to optimize the drilling performance during real-time rotary drilling operations. Monitoring the HDI in actual field conditions can help the driller evaluate the ongoing drilling operation's reliability. Fallouts from the comparison disclose that the excessive energy spent for the low ROP was due to inappropriate drilling parameters chosen for a particular formation. This work can contribute to the effective and accurate evaluation of operating parameters and conditions by utilizing surface readings alone where no downhole sensors/equipment were employed. The proposed model was validated in a directional well that was drilled in the north-eastern parts of India. • The reverse-engineering technique and the input energy module are utilized to determine the optimal drilling parameters. • Surface measurements are adequate, avoiding the costly downhole sensors and equipment. • The hydraulic drilling impact (HDI) is proposed for real-time drilling evaluation. • The holistic approach can be implemented in directional wells that are driven by the potential of cost reduction.

DEVELOPMENT AND BENCH TESTS OF A PHYSICAL MODEL OF REVERSIBLE HYDRAULIC IMPACT DEVICE

The paper presents a physical model of reversible one-way hydraulic impact device (with two striker movement limiters). The researches helped to develop the design of the device and a test bench simulating the resistance of the medium in case of possible body movement. Tests of a hydraulic impact device with a rigidly sealed body showed its efficiency in the operating modes obtained in the calculations: when changing the flow rate of the liquid, the striker strikes both in the forward and reverse directions.

Magnetomechanical response of a steel monopile during impact pile driving

This paper reports on a measurement campaign in which the magnetomechanical response of a steel monopile is recorded during installation with a hydraulic impact hammer. By comparing impact-induced changes in the magnetic stray field of the structure to the measured strain, this effect is analysed for the first time under dynamic loading conditions on such a large scale. It is shown that the measured stray field displays an excellent correspondence with the strain in terms of frequency content and amplitude ratio for hammer blows that induce compressive strain pulses of different magnitude. Using the data, a non-contact method is developed and validated to infer the hammer-induced strains using the dynamic magnetic stray field. The proposed method can be applied during pile installations when the use of conventional strain measurement devices is challenging, e.g. in the offshore environment.

Evaluation on the Effect of Pressure Transients on Rock Joints in Unlined Hydropower Tunnels Using Numerical Simulation

Frequent pressure transients are identified as the cause of block failures in many unlined hydropower tunnels. The primary design objective of such tunnels is to prevent hydraulic jacking at design static pressure and mass oscillation but neglects the effect of short transients, i.e., water hammer. The issue has not been studied from the perspective of hydro-mechanical interactions due to frequent pore pressure changes in the rock mass. This article mainly focuses on the effect of pressure transients at different static heads, or different effective normal stresses across the joints and the effect of time period of pressure transient. Further, the change in such behaviour due to different mechanical properties of rock joints, such as stiffness, friction angle and dilation, is investigated. Numerical simulations of observed pore pressure response in the rock mass during a pressure transient are carried out using distinct element code 3DEC. The results show that relative joint deformation due to short pressure transients are the highest when joint normal stresses are 1.5–2.5 times higher than static water pressure in the tunnel and thus the vulnerability to weakening of such joints by hydraulic fatigue is higher. Further, results show that water hammers can travel up to 4 m into the rock mass even in stiff joint conditions and sufficiently high normal stresses. Results further indicate that the hydraulic impact due to water hammer is smaller as compared to mass oscillation. It is concluded that water hammers, wherever applicable along the waterway, can still contribute to hydraulic fatigue of rock joints in addition to the effect of mass oscillation and cannot be neglected when pressure transients occur frequently. Tunnel filling/dewatering and mass oscillations cause macroscopic joint displacements or block movements over long-term operation which is the major cause of block falls in unlined pressure tunnels.

Aspects of Strength Testing of Tank Containers in Compliance with the Requirements of the UN Navigation Rules and Regulations

This article deals with the method of computer-aided studies of the results of tank container impact tests to confirm the ability of portable tanks and multi-element gas containers to withstand the impact in the longitudinal direction on a specially equipped test rig or using a railway flat car by impacting a flat car with a striking car, in compliance with the requirements of the UN Navigation Rules and Regulations. It is shown that the main assessed characteristic of the UN requirements is the spectrum of the shock response (accelerations) for the interval natural frequencies of the shock pulse. The calculation of the points of the shock response spectrum curve based on the test results is reproduced in four stages. A test configuration of the impact testing of the railway flat car with a tank container is presented, and the impact is performed in such a way that, under a single impact, the shock spectrum curve obtained during the tests for both fittings subjected to impact repeats or exceeds the minimum shock spectrum curve for all frequencies in the range of 2 Hz to 100 Hz. Formulas for determining the relative displacements and accelerations for the interval natural frequencies of the shock wave are given. The research results are presented in graphical form, indicating that the experimental values of the shock response spectrum exceed the minimum permissible values; the equation of the experimental curve of the shock response spectrum in the frequency range 0–100 Hz is described by power-law dependence. The coefficients of the equation were determined by the statistical method of maximum likelihood with the determination factor being 0.897, which is a satisfactory value; a comparative analysis showed that the experimental curve of the impact response spectrum in the frequency range 0–100 Hz exceeds the normalized curve, which confirms compliance with regulatory requirements. A new test configuration is proposed using a tank car with a bulk liquid, the processes in which upon impact differ significantly from other freight wagons under longitudinal impact loads of the tank container. The hydraulic impact resulting from the impact on the tank container and the platform creates an overturning moment that causes the rear fittings to be unloaded.

Use of a group of underwater hydraulic tarans for the water supply system

When choosing water-lifting equipment, a number of issues related to the type of water intake structure, the energy for driving the plant, the adopted pressure and control structures, and the automation system are solved. Their structures should be simple, convenient to operate, have an affordable cost, provide the required water supply to the above areas. For agricultural water supply and irrigation of land plots located above the water source, the equipment for lifting water using the energy of the water flow - a hydraulic ram - fully meets the requirements of all known means of mechanizing the water lift. The cascade hydraulic unit operates due to dispersed energy of open water flows and hydraulic impact energy. The use of a cascade hydraulic ram plant on the river will allow the water supply of individual consumers without the cost of electricity, which is absolutely safe for the environment. The proposed topic of work is therefore very relevant.

Integrated technology for multistage drainage of coal seams before high-rate cutting

An increase in the depth of underground coal mining leads to an increase in gas content, to a decrease in gas permeability, and, as a result, to a decrease in the mine drainage efficiency. The article presents the actual data on implementation of the integrated multistage pre-mine drainage technology using surface and underground boreholes in Kirov Mine of SUEK-Kuzbass. The actual estimate of the improved underground hydraulic fracturing efficiency is made by a number of objective factors identified during underground coal production in the hydraulic fracturing zones and in the check zones. These objective factors are the increase in output per face, decrease in methane emission in longwalls and the reduction in downtime of mining equipment by gas criterion. The study results on the effective parameters of the underground fracturing technology are presented, namely, the fluid injection rate, effective (useful) length of fracturing wells and the fluid injection volume. The article gives the actual data on hydraulic impact exerted on a coal seam unloaded from rock pressure using surface boreholes. It is shown that the main impact mode is hydraulic splitting, sometimes with microhydrofractures created at high rates of fluid injection into the coal seam. The prospects of further improvement in hydraulic coal splitting from ground surface are based on implementation of selfsustaining coal destruction and on using the effect of coal swelling in the process zone. The authors appreciate participation of A. V. Malafeev, I. A. Kurmanov, E. A. Kvitko, V. I. Gavrilov, I. A. Komissarov, S. L. Demin, A. B. Letashkov, I. V. Chaldin and other experts from SUEK-Kuzbass in the preparation and implementation of the tests.

Artificial aquifer recharge and pumping: transient analytical solutions for hydraulic head and impact on streamflow rate based on the spatial superposition method

The behaviour of transient groundwater mounds in response to infiltration from surface basins has been studied for decades, but some common settings still lack analytical solutions. It has been shown that applying mathematical integration to the line-sink solution developed by Hantush in the 1960s for pumping an unconfined aquifer, considering recharge over the surface of a defined area, is identical to his solution for groundwater mounding below a rectangular basin. This implies that the superposition principle can, generally, be used to directly include pumping wells, as well as aquifer boundaries, to derive a unique solution. Moreover, other line-sink solutions can be used with a spatial superposition method for addressing a variety of hydrogeological settings, provided the behaviour of the relevant partial differential equations is linear. Based on this principle and on existing line-sink solutions, several analytical solutions are proposed that are able to consider a rectangular recharging area and a pumping well in an unconfined aquifer: (1) near a stream, (2) between a stream and a no-flow boundary, with and without the influence of natural recharge, (3) near a stream that partially penetrates an aquifer and (4) for a multi-layer aquifer. For cases including streams, transient solutions of the impact on streamflow rate are also presented. The proposed analytical solutions will be of practical use for managed aquifer recharge, in particular the design of structures for artificially recharging an aquifer, possibly pumped by one or several wells.

Sediment transport and roughness coefficients generated by flexible vegetation patches in the emergent and submerged conditions in a semiarid alluvial open-channel

In the semiarid environment, low vegetation cover and deforestation on the banks of rivers represent a strong impact on the flow resistance process, altering the interaction of the flow with the banks, one of the conditioning factors of the morphological balance of the river channel. In extreme hydrological events, turbulence and high speeds can cause a marked erosion process at the banks, increasing the sediment yield. This study aimed to monitor water and solid discharges through direct hydrosedimentometric measurements, as well as to estimate, using a simplified model based on force balance, the hydraulic roughness coefficients generated by flexible vegetation element of the Ipomoea pes-caprae species under emergent and submerged conditions. The total annual rainfall for 2019 was 748.5 mm year−1, above the historical mean (642.80 mm year−1). The mean depth (h = 0.24 m) and flow (Ql = 0.15 m3 s−1) rates were highly correlated as a power function (R2 = 0.8041). In general, without specifically considering the effect of vegetation, the flow regime was characterized as turbulent and subcritical flow (Re = 66,634.65 dim. and Fr = 0.16 dim.), respectively. The suspended sediment concentration (CSS), suspended sediment (QSS) and bedload (QBed) discharges presented mean values of 409.41 mg L−1, 6.23 t day−1 and 0.069 t day−1, respectively. The total sediment yield (Yt) was 1.90 t km−2 year−1. The vegetation effect was analyzed on the right (RB) and left (LB) banks, where the stems of I. pes-caprae were concentrated between 0.22 and 0.40 m and 0.66–1.20 m from the banks, respectively. On the RB, the shear (1.0 < Sr < 1.95), free flow (0.27 < Sr < 1.0) and the transition (Sr = 1) zones were identified. On the LB, just emergent condition (Sr < 1.0) was indetified. The following relationship were found between vegetation drag coefficient (C′D), stem Reynolds number (Red), plant density Reynolds number (Rev) and Froude number (Fr) on the RB: C′D (1.22–12.46 m−1); Red (567 < Red < 2224), Rev (1305 < Rev < 35,011) and Fr = 0.14; on the LB: C′D (2.10–1168.29 m−1); Red (57 < Red < 1427), Rev (2615 < Rev < 167,534) and Fr = 0.08. These results demonstrate that the aquatic vegetation directly influences the river dynamics; the density vegetation having a hydraulic impact on the flow transport capacity, that is, as the C′D increases, it increases the resistance of the vegetation to the flow and decreases the capacity of transport of sediments.

Learning Safe and Optimal Control Strategies for Storm Water Detention Ponds

Abstract Storm water detention ponds are used to manage the discharge of rainfall runoff from urban areas to nearby streams. Their purpose is to reduce the hydraulic impact and sediment loads of the receiving waters. Detention ponds are currently designed based on static controls: the output flow of a pond is capped at a fixed value. This is not optimal with respect to the current infrastructure capacity and for some detention ponds it might even violate current regulations set by the European Water Framework Directive. We apply formal methods to synthesize (i.e., derive automatically) a safe and optimal active controller. We model the storm water detention pond, including the urban catchment area and the rain forecasts, as a hybrid Markov decision process. Subsequently, we use the tool Uppaal Stratego to synthesize a control strategy minimizing the cost related to pollution (optimality) while guaranteeing no emergency overflow of the detention pond (safety). Simulation results for an existing pond show that Uppaal Stratego can learn optimal strategies that prevent emergency overflows, where the current static control is not always able to prevent it. At the same time, our approach can improve sedimentation during low rain periods.

Dynamics of One-Way Hydraulic Impact System with Two Piston Stop Tools

Dynamics of One-Way Hydraulic Impact System with Two Piston Stop Tools

SOME EXAMPLES OF NUMERICAL MODELING OF NON-STEADY LIQUID FLOWS IN SIMPLE AND BRANCHED PIPELINES

In this paper we suggest to develop the theoretical approach and numerical modeling for non-steady turbulent transport of liquid flows in simple and branched pipelines. The basic problems for non-steady flows, such as starting and stopping of hydraulic pipeline systems, hydraulic impact and other were studied. Some concrete numerical algorithms for simulation of such kind of non-steady flows were also proposed in this paper.

INFLUENCE OF PRESSURE OSCILLATIONS IN COMMON RAIL INJECTOR ON FUEL INJECTION RATE

Fuel injection causes considerable oscillations of fuel pressure at the injector inlet. One of the reasons is hydraulic impact when the needle valve closes. For multiple injections, the previous injections affect the following. As both the fuel pressure in rail pac and the injection rate grow, the oscillations increase. The pressure oscillation range at the common rail injector inlet at pac=1500 bar is up to 350 bar, and at the rail pressure pac=500 bar, the amplitude decreases to 80 bar. Physical properties of the fuel are also important. As the viscosity of the fuel increases, its hydraulic friction grows which results in a rapid damping of pressure oscillations. The data for an injector operating on sunflower oil is presented. As compared with diesel fuel, the oscillations range decreases from 400 to 250 bar at the same operating mode. The influence of the interval between the impulses of a double injection on the injection rate of the second fuel portion was investigated. Superposition of two waves during multiple injections may result in amplification and damping of the oscillations. Simulation was performed to estimate the influence of fuel type and time interval Δτ between control impulses of a double injection on the injection quantity of the second portion at pressures of 2000-3000 bar. When the rail pressure pac grows, the oscillations and their impact on the injection process increase. For diesel fuel at pressure of pac=2000 bar, the variation in injection rates of the second portion is 2.36-4.62 mg, and at pac=3000 bar – 1.58-6.63 mg.

Results of steel 20Kh13 samples with combined hardened-structured surface erosion tests

The work presents the results of erosion tests and metallographic studies of samples from blade steel 20Kh13 with diffusion coating obtained by ion nitriding and samples from nitrided steel 20Kh13 with a relief previously formed on the surface. Studies of the samples resistance to high-speed water droplet erosion were carried out using the unique hydraulic impact rig «Erosion-M» of the NRU «MPEI». It was established that the use of nitriding and nitriding with preliminary surface structuring allows increasing the relative erosion resistance in the area with a maximum wear rate of at least 2 times, and in the area with a steady wear rate of at least 3 times. It was also found that structuring the surface layer before the nitriding process allows reducing the wear rate in the area with a maximum erosion rate compared to the nitrided surface by at least 10%.