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1
Sugimura, Ken, and Katsumasa Suzuki. "Using Intermittently Operated Oil Hydraulic Pump Unit with Accumulator to Save Energy." International Journal of Automation Technology 6, no. 4 (July 5, 2012): 426–33. http://dx.doi.org/10.20965/ijat.2012.p0426.
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Efforts to save energy have been made in a number of fields due to a shortage of energy resources, such as oil, and a need to protect the earth’s environment. In the field of hydraulics, energy saving pump units are very important because of the energy they consume. At present, a variable displacement-type hydraulic pump units (VD pump unit) and inverter control-type pump units (INV pump unit) are widely used. In this paper, the authors propose using an intermittently operated pump unit coupled with an accumulator (ACC pump unit). First, the electric power consumption, pump output pressure, rotation speed, and efficiency of three types pump units are measured when the same work is done using a modeled machine tool. Next, the load is abstracted to clarify the general characteristics of intermittent work, and the electric power consumption and efficiency of each pump unit are measured. Finally, the static characteristics of each pump unit are measured, and it is verified that the ACC pump unit saves the most energy.
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Feng, Qian, Huang Jiesheng, Liu Jingjun, and Liu Honghu. "Effects of flow hydraulics on total nitrogen loss on steep slopes under simulated rainfall conditions." Hydrology Research 49, no. 4 (May 12, 2017): 1088–100. http://dx.doi.org/10.2166/nh.2017.261.
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Abstract Flow hydraulics play important roles in soil erosion and loss of soil nutrients. A better understanding of the relationship between flow hydraulics and nutrient losses will improve chemical transport modeling. The laboratory experiment was conducted to determine flow hydraulics' effects on total nitrogen (TN) loss. The impacts of rainfall intensities (0.6, 1.1, 1.61, 2.12, and 2.54 mm·min−1) and slope gradients (10°, 15°, and 20°) on TN loss were also studied. Selected soils were derived from purple sandy shales, which are the main parent materials in Wangjiaqiao watershed, southern China. Results show that negative linear relationships (R2 = 0.71) were observed between the rate of Manning roughness coefficient to average flow depth and the unit area runoff-associated TN transport rate. There was a good linear relationship between the unit area sediment-associated TN transport rate and Reynolds numbers (R2 = 0.90), flow velocity (R2 = 0.87), and stream power (R2 = 0.73), while Froude numbers, Darcy–Weisbach and Manning friction coefficients were not good hydraulic indicators of the sediment-associated TN loss of purple soil. The equation including stream power and flow velocity may have a better correlation coefficient (R2 = 0.94).
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Yang, Hukun, Jianping Wang, and Hui Liu. "Energy-saving mechanism research on beam-pumping unit driven by hydraulics." PLOS ONE 16, no. 4 (April 1, 2021): e0249244. http://dx.doi.org/10.1371/journal.pone.0249244.
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Aiming to solve the problems of long transmission chain, large movement inertia of components and high energy consumption of pumping units, this proposes a new pumping unit with direct balance and hydraulic drive. Through mathematical modeling and simulation analysis to compare the suspension dynamic characteristics and balance characteristics of the hydraulically driven pumping unit with the conventional one. It turns out that the suspension maximum speed drop 21.14%, the maximum acceleration drops 28.88% and the root mean square torque drops 92.9% on the suspension of the hydraulically driven pumping unit. The experimental results proves that the hydraulically driven pumping unit has significant energy saving efficiency, and achieves more than 30.9% of active power saving rate. Theoretical and practical research results show that hydraulically driven pumping unit is reliable and better energy saving, which provides a basis in theory and engineering practice in application.
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Hadadin, N. "Spatial stochastic and analytical approaches to describe the complex hydraulic variability inherent channel geometry." Hydrology and Earth System Sciences Discussions 8, no. 4 (July 19, 2011): 6967–92. http://dx.doi.org/10.5194/hessd-8-6967-2011.
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Abstract. The effects of basin hydrology on channel hydraulic variability for incised streams were investigated using available field data sets and models of watershed hydrology and channel hydraulics for Yazoo River Basin, USA. The study presents the hydraulic relations of bankfull discharge, channel width, mean depth, cross- sectional area, longitudinal slope, unit stream power, and runoff production as a function of drainage area using simple linear regression. The hydraulic geometry relations were developed for sixty one streams, twenty of them are classified as channel evaluation model (CEM) Types IV and V and forty one of them are streams of CEM Types II and III. These relationships are invaluable to hydraulic and water resources engineers, hydrologists, and geomorphologists, involved in stream restoration and protection. These relations can be used to assist in field identification of bankfull stage and stream dimension in un-gauged watersheds as well as estimation of the comparative stability of a stream channel. Results of this research show good fit of hydraulic geometry relationships in the Yazoo River Basin. The relations indicate that bankfull discharge, channel width, mean depth, cross-sectional area have stronger correlation to changes in drainage area than the longitudinal slope, unit stream power, and runoff production for streams CEM Types II and III. The hydraulic geometry relations show that runoff production, bankfull discharge, cross-sectional area, and unit stream power are much more responsive to changes in drainage area than are channel width, mean depth, and slope for streams of CEM Types IV and V. Also, the relations show that bankfull discharge and cross-sectional area are more responsive to changes in drainage area than are other hydraulic variables for streams of CEM Types II and III. The greater the regression slope, the more responsive to changes in drainage area will be.
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Shen, Nan, Zhanli Wang, Qingwei Zhang, Hao Chen, and Bing Wu. "Modelling soil detachment capacity by rill flow with hydraulic variables on a simulated steep loessial hillslope." Hydrology Research 50, no. 1 (August 23, 2018): 85–98. http://dx.doi.org/10.2166/nh.2018.037.
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Abstract Modelling soil detachment capacity by rill flow with hydraulic variables is essential to understanding the rill erosion process and developing physically based rill erosion models. A rill flume experiment with non-erodible flume bed and small soil samples was conducted. Seven flow discharges and six steep slope gradients were combined to produce various flow hydraulics. The soil detachment capacity increases with the increase in slope gradient and flow discharge. The critical slope gradients of 21.26 and 26.79% cause the detachment capacity to increase at a slow pace. The soil detachment capacity can be defined by a power function of flow discharges and slopes. The contribution rates of slope gradient and flow discharge to soil detachment capacity are 42 and 54%, respectively. The soil detachment capacity increases with shear stress, stream power and unit stream power; the increase rates of these parameters are greater under gentle slopes than steep slopes. Stream power is the superior hydrodynamic parameter describing soil detachment capacity. The linear model equation of stream power is stable and reliable, which can accurately predict soil detachment capacity by rill flow on steep loessial hillslopes. This study can help to sufficiently clarify the dynamic mechanism of soil detachment and accurately predict soil detachment capacity for steep loessial hillslopes.
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Akdemir, Bayram. "Novel Intelligent and Sensorless Proportional Valve Control with Self-Learning Ability." Journal of Sensors 2016 (2016): 1–6. http://dx.doi.org/10.1155/2016/8141720.
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Linear control is widely used for any fluid or air flows in many automobile, robotics, and hydraulics applications. According to signal level, valve can be controlled linearly. But, for many valves, hydraulics or air is not easy to control proportionally because of flows dynamics. As a conventional solution, electronic driver has up and down limits. After manually settling up and down limits, control unit has proportional blind behavior between two points. This study offers a novel valve control method merging pulse width and amplitude modulation in the same structure. Proposed method uses low voltage AC signal to understand the valve position and uses pulse width modulation for power transfer to coil. DC level leads to controlling the valve and AC signal gives feedback related to core moving. Any amplitude demodulator gives core position as voltage. Control unit makes reconstruction using start and end points to obtain linearization at zero control signal and maximum control signal matched to minimum demodulated amplitude level. Proposed method includes self-learning abilities to keep controlling in hard environmental conditions such as dust, temperature, and corrosion. Thus, self-learning helps to provide precision control for hard conditions.
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Masood, Khayyam, Xavier Dauptain, Matteo Zoppi, and Rezia Molfino. "Hydraulic Pressure-Flow Rate Control of a Pallet Handling Robot for an Autonomous Freight Delivery Vehicle." Electronics 9, no. 9 (August 24, 2020): 1370. http://dx.doi.org/10.3390/electronics9091370.
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The current paper presents an upgrade of a pre-installed hydraulic system for the operation of a pallet handling robot for a freight delivery vehicle known as FURBOT (freight urban robotic vehicle). The automated forklift installed on FURBOT for loading/unloading of cargo is powered with the help of hydraulics. The previous hydraulic system worked via a classical approach with a fixed displacement pump and a bypass valve, making it work on full power when in use. An alternative design was proposed, simulated and installed on FURBOT; it uses a fixed displacement pump and changes the rotation speed in real time using a pressure sensor. Novelty was attained with the use of gear pumps for said scenario. A control algorithm is implemented in the processing unit for controlling the speed of the motor driving the pump. The main advantage of this approach is better use of energy for the vehicle’s battery. The aim of this research is to control both the speed and maximum force exerted by the actuators with the help of a single sensor and an inexpensive pump.
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Price, Dean, Majdi I. Radaideh, Travis Mui, Mihir Katare, and Tomasz Kozlowski. "Multiphysics Modeling and Validation of Spent Fuel Isotopics Using Coupled Neutronics/Thermal-Hydraulics Simulations." Science and Technology of Nuclear Installations 2020 (July 26, 2020): 1–14. http://dx.doi.org/10.1155/2020/2764634.
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Multiphysics coupling of neutronics/thermal-hydraulics models is essential for accurate modeling of nuclear reactor systems with physics feedback. In this work, SCALE/TRACE coupling is used for neutronic analysis and spent fuel validation of BWR assemblies, which have strong coolant feedback. 3D axial power profiles with coolant feedback are captured in these advanced simulations. The methodology is applied to two BWR assemblies (2F2DN23/SF98 and 2F2D1/F6), discharged from the Fukushima Daini-2 unit. Coupling is performed externally, where the SCALE/T5-DEPL module transfers axial power data in all axial nodes to TRACE, which in turn calculates the coolant density and temperature for each of these nodes. Within a burnup step, the data exchange process is repeated until convergence of all coupling parameters (axial power, coolant density, and coolant temperature) is observed. Analysis of axial power, criticality, and coolant properties at the assembly level is used to verify the coupling process. The 2F2D1/F6 benchmark seems to have insignificant void feedback compared to 2F2DN23/SF98 case, which experiences large power changes during operation. Spent fuel isotopic data are used to validate the coupling methodology, which demonstrated good results for uranium isotopes and satisfactory results for other actinides. This work has a major challenge of lack of documented data to build the coupled models (boundary conditions, control rod history, spatial location in the core, etc.), which encourages more advanced methods to approximate such missing data to achieve better modeling and simulation results.
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Barth, Eric J., Mark E. Hofacker, and Nithin Kumar. "A Free-Liquid-Piston Engine Compressor for Compact Robot Power." Mechanical Engineering 135, no. 06 (June 1, 2013): S10—S12. http://dx.doi.org/10.1115/1.2013-jun-7.
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This article focuses on the use of a free-liquid-piston engine compressor (FPEC) for compact robot power. The FPEC presented in the article combines the engine and the compressor into a single unit. FPEC, a high-power density form of actuation, can help operate human-scale robots. An energy source that provides pneumatic power presents an appealing alternative that alleviates many of the scalability problems of hydraulics while preserving a high actuation power density. The system also presents additional advantages such as power-on-demand with no idle. Taking advantage of the high inertance piston, high-pressure air and high vapor pressure fuel enable the engine to operate in an inject and fire cycle. Dynamically, the FPEC is similar to a bug converter circuit in that the flow is amplified and the high-inheritance piston plays the same energetic role as the inductor. The data suggests that pneumatic systems using the FPEC as a power source would exhibit system energy densities comparable to, if not better than, the best electrochemical systems.
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Watson, Bruce, Mark Rupke, Imre Takács, and Gilles Patry. "MODELLING OF FULL-SCALE WASTEWATER TREATMENT PLANTS: HOW DETAILED SHOULD IT BE?" Water Science and Technology 30, no. 2 (July 1, 1994): 141–47. http://dx.doi.org/10.2166/wst.1994.0037.
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Dynamic mathematical modelling of full-scale wastewater treatment plants requires an optimal level of detail to be accurate, effective, but still manageable. Single process models tend to oversimplify the complexities of a large-scale plant and result in erroneous calibrated parameter values or limited predictive power for the model – on the other hand, modelling of every process and process unit is usually impractical, since it cannot be supported by reliable plant data, and requires prohibitive sampling costs and effort. Level of aggregation, settler dimensionality and reactivity, and plug-flow hydraulics were investigated with the help of a sophisticated dynamic modelling package. The results show that there is no general rule or global ‘optimal level’ of modelling – the required modelling detail is a function of influent flow and loading levels, and processes to be simulated (BOD removal, nitrification-denitrification, biological phosphorus removal, settling). In the case of real-life plants, supportable modelling level is often constrained by data availability and reliability.
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Li, Zhenhe, Jinchun Song, Yanjun Huang, Yungong Li, and Jianwen Chen. "Design and analysis for a new energy-saving hydraulic pumping unit." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 12 (June 15, 2017): 2119–31. http://dx.doi.org/10.1177/0954406217715484.
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With the increasing concern over global energy crisis, energy saving in pumping units is becoming a significant subject. In terms of energy-saving and working efficiency, hydraulic pumping units outperform conventional pumping units. In this paper, a novel hydraulic pumping unit is proposed to overcome the existing drawbacks of conventional pumping units and present hydraulic pumping units. Firstly, this novel hydraulic pumping unit adopts a balanced mechanical structure, which means two oil wells are used in this system and the weight of their sucker rods can balance each other through the symmetrical arrangement. This kind of structural design not only saves the nominal power but also allows the system to continuously pump oil. Another feature of this hydraulic pumping unit is that it adopts the electro-hydraulic proportional load-sensing control technology, which makes the pressure and flow rate of the pump adapt to the requirement automatically in real time. The double wells of the system work alternatively under the normal condition and any one can work alone when the other needs maintenance, which improves the operating rate of pumping oil. After the main system parameters are calculated, conclusion can be drawn that both the nominal and operating power of this hydraulic pumping unit are relatively low. The model of the whole system is built based on mathematical dynamics and AMESim environment, and simulation results demonstrate that the proposed hydraulic pumping unit can achieve remarkable energy-saving performance.
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Fuamba, Musandji, Gilles Brosseau, and Éric Mainville. "Determination of head losses in a surge chamber: Robert Bourassa power plant case study." Canadian Journal of Civil Engineering 34, no. 9 (September 1, 2007): 1038–47. http://dx.doi.org/10.1139/l07-021.
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Optimal management of power plant units is achieved when the global efficiency of the units and the minimization of the total hydraulic head losses through the water transportation systems can be combined. Evaluating these hydraulic head losses appears to be very difficult due to the complexity of the flow conditions through the hydraulic structures. A hydraulic energy based method to determine head losses in the surge chamber has been proposed in this paper, as well as a method to manage the opening of units which would optimize the production of electricity. This method was applied to a case study, and successful results have been obtained showing how the head loss varies in the surge chamber.Key words: hydraulic head losses, power plant unit, surge chamber, unit efficiency, three-dimensional flow conditions, turbulent flow models, computational fluid dynamics.
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Fadil, Salih, Cüneyt Demir, and Burak Urazel. "Solution to Security Constrained Environmental Pumped-Storage Hydraulic Unit Scheduling Problem by Genetic Algorithm." ISRN Power Engineering 2013 (September 22, 2013): 1–12. http://dx.doi.org/10.1155/2013/717625.
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A lossy electric power system area that contains thermal units and a pumped-storage (p-s) hydraulic unit is considered in this paper. The cost function, which is weighted combination of the total fuel cost and the total emission cost of the thermal units, in an operation cycle, is minimized under some possible electric and hydraulic constraints. The dispatch technique that is based on genetic algorithm considers minimum and maximum reservoir storage limits of the p-s unit, upper and lower active and reactive generation limits of the thermal units, upper and lower active pumping/generation power limits of the p-s unit, maximum transmission capacities of the transmission lines, and upper and lower limits of the bus voltage magnitudes in a considered power system. The proposed dispatch technique was tested on an example power system that has 12 buses with five thermal units and a p-s hydraulic unit. The same dispatch problem is solved via an iterative solution method based on modified subgradient algorithm operating on feasible values (F-MSG) and pseudowater price just for comparison purpose. It is seen that the solution technique based on the F-MSG algorithm and pseudowater price gives similar results with the proposed algorithm based on genetic algorithm.
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Wang, Hua Bing, and Jun Ke Hu. "Durability Testing System with Power Recycle for the Variable Displacement Closed-Loop Hydraulic Pumps." Applied Mechanics and Materials 241-244 (December 2012): 1333–37. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.1333.
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A testing system scheme with power recycle for hydraulic pumps’ durability is present, which is based on a hydraulic motor with hydraulicly overridden pressure compensation. The hydraulic motor can adaptively adjust its displacement to meet the demand of displacement match of the power feedback in the system. The system pressure can be set by adjusting the starting control pressure of the motor. The rotating speed of the pump is guaranteed by the control of the driven electrical motor. A hydraulic bridge unit is used to guide the flow from the outport of the pump to the fixed inlet port of the hydraulic motor and thus causes the motor to rotate in a certain direction to drive the pump in order to recycle the power.
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Li, Guang Ming, Kai Cheng, and Li Yan. "Optimal Design of Main Parameters for Pumping Unit of Automotive Power Steering Units." Advanced Materials Research 199-200 (February 2011): 1441–44. http://dx.doi.org/10.4028/www.scientific.net/amr.199-200.1441.
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We should clean the internal residual hydraulic oil after the automotive power steering units are carried out performance test according to the requirements. In the sake of pumping more residual hydraulic oil efficiently we develop the special pumping unit Based on the orthogonal test, the optimal design of the main parameters pumping unit of automotive power steering units that is the first adding gas time, adding gas interval and adding gas time has been completed in order to determine the optimal program to achieve the best pumping effect.
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Bosak, Mykola, Oleksandr Hvozdetskyi, Bohdan Pitsyshyn, and Serhii Vdovychuk. "THE RESEARCH OF CIRCULATION WATER SUPPLY SYSTEM OF POWER UNIT OF THERMAL POWER PLANT WITH HELLER COOLING TOWER." Theory and Building Practice 2020, no. 2 (November 20, 2020): 1–9. http://dx.doi.org/10.23939/jtbp2020.02.001.
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Analytical hydraulic researches of the circulating water cooling system of the power unit of a thermal power plant with Heller cooling tower have been performed. Analytical studies were performed on the basis of experimental data obtained during the start-up tests of the circulating water cooling system of the “Hrazdan-5” power unit with a capacity of 300 MW. Studies of the circulating water cooling system were carried out at an electric power of the power unit of 200 - 299 MW, with a thermal load of 320 - 396 Gcal/hr. By circulating pumps (CP), water mixed with condensate is fed to the cooling tower, from where it is returned through the turbine for spraying by nozzles in the turbine steam condenser. An attempt to increase the water supply to the condenser by increasing the size of the nozzles did not give the expected results. The amount of the water supply to the circulating pumping station depends on the pressure loss in the circulating water cooling system. The highest pressure losses are in hydro turbines (HT), which are part of the circulating pumping station. Therefore, by adjusting the load of the hydro turbine, with a decrease in water pressure losses, you can increase the water supply by circulating pumps to the condenser. Experimental data and theoretical dependences were used to calculate the changed hydraulic characteristics of the circulating water cooling system. As a result of reducing the pressure losses in the section of the hydro turbine from 1.04 to 0.15 kgf/cm2, the dictating point for the pressure of circulating pumping station will be the turbine steam condenser. The thermal power plant cooling tower is designed to service two power units. Activation of the peak cooler sectors of the cooling tower gives a reduction of the cooled water temperature by 2-4 °С only with the spraying system.
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Niri, M. Emami, and D. E. Lumley. "Probabilistic Reservoir-Property Modeling Jointly Constrained by 3D-Seismic Data and Hydraulic-Unit Analysis." SPE Reservoir Evaluation & Engineering 19, no. 02 (February 18, 2016): 253–64. http://dx.doi.org/10.2118/171444-pa.
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Summary We present a new method for seismic reservoir characterization and reservoir-property modeling on the basis of an integrated analysis of 3D-seismic data and hydraulic flow units, and apply it to an example of a producing reservoir offshore Western Australia. Our method combines hydraulic-unit analysis with a set of techniques for seismic reservoir characterization including rock-physics analysis, Bayesian inference, prestack seismic inversion, and geostatistical simulation of reservoir properties. Hydraulic units are geologic layers and zones characterized by similar properties of fluid flow in porous permeable media, and are defined at well locations on the basis of logs, core measurements, and production data. However, the number of wells available for hydraulic-unit analysis is often extremely limited. In comparison, the lateral coverage and resolution of 3D-seismic data are excellent, and can thus be used to extend hydraulic-unit analysis away from well locations into the full 3D reservoir volume. We develop a probabilistic relationship between optimal 3D-seismic-data attributes and the hydraulic units that we determine at well locations. Because porosity and permeability distributions are estimated for each hydraulic flow unit as part of the process, we can use the 3D-seismic probabilistic relationships to constrain geostatistical realizations of porosity and permeability in the reservoir, to be consistent with the flow-unit analysis. Reservoir models jointly constrained by both 3D-seismic data and hydraulic flow-unit analysis have the potential to improve the processes of reservoir characterization, fluid-flow performance forecasting, and production data or 4D-seismic history matching.
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Alhakawati, M. S., N. B. Cooper, S. Al Asmi, M. Abu El Soud, and H. Abdulhussain. "Commissioning and operation experience of the largest flat sheet membrane bio-reactors in the world." Water Practice and Technology 9, no. 2 (June 1, 2014): 165–78. http://dx.doi.org/10.2166/wpt.2014.020.
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The Al Ansab sewage treatment plant (STP) serves the central area of Muscat, the capital of Oman. When commissioned in 2010, the plant was the largest flat-plate membrane bioreactor facility in the world, with an initial capacity of 55,000 m3/day. Expansion to 125,000 m3/day is under design and when operational in 2016 the plant will once again be one of the largest MBRs of its kind in the world. With limited space available, and a desire for consistent high quality effluent for full public access applications, the membrane bio-reactor (MBR) process was selected as the treatment technology for the plant. The plant equipment and tankage installed under the first phase was sized to serve a maximum month average flow rate of 55,000 m3/day, while buildings, hydraulics, interconnecting piping and electrical power supply were sized to serve the second phase total capacity of 84,000 m3/day. Kubota EK400 flat sheet membranes of 0.4 μm pore size were selected for the MBR. Eight membrane tanks were provided in the first phase, each having 40 double stacked membrane units. Each double stacked unit has 400 membrane panels making the total membranes sheets installed in the first phase over 120,000 panels. Al Ansab MBR plant expansion to the second phase is currently under detailed design and the new Kubota membranes module RW400 will be used in this phase. The plant was designed to accept sewage delivered by sewer networks. Due to delay in completing the sewer network the new plant was commissioned using trucked sewage diverted from the old plant. This is a non-standard condition for the MBR plant, and Haya implemented several modifications in anticipation of this situation. The high volume of trucked wastewater was addressed with flow and load equalization systems to dampen the impact of shock loading. The Al Ansab STP is performing very well and complying with all the required effluent standards. Many lessons have been learned in both the design and operation of such a large MBR plant.
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Qu, Zhi Yong, and Zheng Mao Ye. "Driving and Power Units Design on Hydraulic Stewart Platform." Applied Mechanics and Materials 58-60 (June 2011): 2434–37. http://dx.doi.org/10.4028/www.scientific.net/amm.58-60.2434.
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Stewart platforms have recently attracted attention as simulator and machine tools because of their conceptual potentials in high motion dynamics and accuracy combined with high structural rigidity due to their closed kinematic loop. Dynamics design of Stewart platform based on Newton-Euler is presented in this paper firstly. Its aim is to compute the velocity and acceleration according to the index given. Meanwhile, the matching rule is put forward in the design of hydraulic power unit, which requires the power capacity of driving units surround the edge of payload. Based on these principles, optimal driving can be obtained practically. This paper, composed of driving units design and optimization, attempts to ground the foundation on dynamics design and choice in the future.
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Liang, Yijie, Tongjian Wang, Xin Wang, Weiquan Liang, and Xinhui Liu. "Simulation research on hydraulic hybrid assistant beam pumping unit." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, no. 11 (April 28, 2015): 1795–804. http://dx.doi.org/10.1177/0954406215584631.
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Conventional beam pumping units have occupied an important position in oilfield equipment due to such characteristics as simple structure, high reliability, simple operation, easy maintenance, and so on. In fact, there are about 90,000 sets of beam pumping units in China. However, the unbalanced structure of the beam pumping units cannot be entirely eliminated because of the inherent geometry and mechanical properties of four-bar linkage, that is the electromotor equivalent torque ripple cannot be absorbed or eliminated by counterweight in up-and-down travels, which causes the electromotor to work under greatly changed load rate with low power factor and high energy consumption. The mechanical relationship of a conventional beam pumping unit was derived first, and then parameters of a basic structure were optimized through dynamic optimization. On this basis, the hydraulic hybrid solution was proposed, and a secondary balance was conducted on the optimal pumping unit electrometer’s load torque. Computer simulation model was established to carry out a system dynamic analysis and the results showed that the scheme can reduce the motor load torque ripple, improve motor load rate and power factor, and reduce motor power effectively. It may bring tremendous decrease of electricity cost and have great significance for oilfield equipment energy saving, oil extraction cost reduction, and promotion of petroleum products’ competitiveness.
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Xu, Ming, Xiao-meng Wu, Xin Yu, and Guo-jin Chen. "Dynamic performance of auxiliary hydraulic power unit based electro-hydraulic variable speed drive system." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 16 (August 24, 2017): 2926–36. http://dx.doi.org/10.1177/0954406217727770.
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Inability of dynamic performances, especially the acceleration response, strongly inhibits the application of electro-hydraulic variable speed drive, even though its intrinsic energy-saving potential. In contrast to variable speed drive, the valve-controlled actuator system shows the capacity of fast response and accurate control precision, but it consumes more energy. The controllable auxiliary power unit based electro-hydraulic variable speed drive system is probably a solution to enhance dynamic performance of variable speed drive on the basis of energy-saving. Except for the principal variable speed power source, there is an auxiliary power source—auxiliary power unit, which is actually a semi-active hydraulic accumulator unit. The auxiliary power unit can detect the relation between the supplied power by power source and the demanded power by actuator, and then release or absorb hydraulic power to improve actuator dynamic response. The dynamic performance of auxiliary power unit based variable speed drive system was investigated experimentally. Firstly, the set-up of proposed drive system was introduced. Dedicated to the complicated characteristics of multi-input-multi-output and strongly nonlinearity, the mathematical model was deduced, and a hierarchical control strategy was illustrated. The experimental results under two typical variable-load conditions were discussed. Furthermore, the comparisons were explained with the other three drive systems, which were valve-controlled motor drive, conventional variable speed drive, and pump-valve compound drive. Based on the experimental results, it is concluded that the auxiliary power unit based variable speed drive demonstrates an excellent dynamic performance, which can significantly improve the actuator response and control precision, as well as obtain a good energy-saving behavior.
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Zhang, Chunyou, Liang Wang, and Hong Li. "Experiments and Simulation on a Late-Model Wind-Motor Hybrid Pumping Unit." Energies 13, no. 4 (February 23, 2020): 994. http://dx.doi.org/10.3390/en13040994.
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Many oil fields are full of wind energy. At present, wind power generation technology has catered to oil fields. A larger wind turbine is used to supply power to several pumping units. As a result of the structural characteristics of the pumping unit, the efficiency of the electromotor is very low, which leads to a reduction in the utilization rate of wind energy. At the same time, considering the high cost of large wind turbines, the energy saving effect is not obvious in practical applications. This paper proposes an energy supply model of a pumping unit driven by a small wind turbine and a new wind-motor hybrid structure. Instead of wind power generation technology, wind energy drives the pumping unit directly via a mechanical–hydraulic transmission system. This new mechanical-hydraulic system can optimize the power confluence of wind and electric power. To enhance the efficiency of the motor, a mathematical model and a test station were established. The correctness of the energy conservation method and the mathematical model was verified, and the performance of the wind-motor system was studied.
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Dobashi, Shuji. "Application of Hydraulic Power Unit to Fin Stabilizer." Marine Engineering 54, no. 1 (January 1, 2019): 77. http://dx.doi.org/10.5988/jime.54.77.
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Cho, Buyoun, Sung-Woo Kim, Seunghoon Shin, Min-Su Kim, Jun-Ho Oh, and Hae-Won Park. "Energy Efficient Control of Onboard Hydraulic Power Unit for Hydraulic Bipedal Robots." Journal of Korea Robotics Society 16, no. 2 (June 1, 2021): 86–93. http://dx.doi.org/10.7746/jkros.2021.16.2.086.
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Jusoh, Mohd Afifi, Zulkifli Mohd Yusop, Aliashim Albani, Muhamad Zalani Daud, and Mohd Zamri Ibrahim. "Investigations of Hydraulic Power Take-Off Unit Parameters Effects on the Performance of the WAB-WECs in the Different Irregular Sea States." Journal of Marine Science and Engineering 9, no. 8 (August 20, 2021): 897. http://dx.doi.org/10.3390/jmse9080897.
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Hydraulic power take-off (HPTO) is considered to be one of the most effective power take-off schemes for wave energy conversion systems (WECs). The HPTO unit can be constructed using standard hydraulic components that are readily available from the hydraulic industry market. However, the construction and operation of the HPTO unit are more complex rather than other types of power take-off, as many components parameters need to be considered during the optimization. Generator damping, hydraulic motor displacement, hydraulic cylinder and accumulator size are among the important parameters that influence the HPTO performance in generating usable electricity. Therefore, the influence of these parameters on the amount of generated electrical power from the HPTO unit was investigated in the present study. A simulation study was conducted using MATLAB/Simulink software, in which a complete model of WECs was developed using the Simscape fluids toolbox. During the simulation, each parameters study of the HPTO unit were separately manipulated to investigate its effects on the WECs performance in five different sea states. Finally, the simulated result of the effect of HPTO parameters on the amount of generated electrical power from the HPTO unit in different sea states is given and discussed.
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Stump, Patrick, Nathan Keller, and Andrea Vacca. "Energy Management of Low-Pressure Systems Utilizing Pump-Unloading Valve and Accumulator." Energies 12, no. 23 (November 21, 2019): 4423. http://dx.doi.org/10.3390/en12234423.
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In the context of improving energy efficiency and fuel consumption of mobile hydraulic equipment, it is important to analyze all the sources of power loss occurring within the hydraulic systems. While plenty of analyses have been performed on the working implements and the main transmission systems, very little attention has been paid to low-pressure (LP) systems until recently. LP systems are required on closed-circuit hydraulic systems to replenish losses, provide cooling flow, and maintain a pilot pressure necessary to operate hydraulic control valves and variable displacement units. It is shown that these circuits, which are often thought to have minimal impact on power consumption, actually cause significant, continuous power loss. A new method of power savings in these circuits is investigated through management of charge pump flow by application of an accumulator-sense pump-unloading (ASPU) valve. This work further proposes the combination of a split LP architecture with an ASPU valve. Three systems are simulated using Simcenter Amesim® and MATLAB/Simulink®. Using realistic duty cycles and unit loss models on a circuit for mobile off-road hydraulic equipment, it is shown that a standard LP system can consume about 5 kW of power. Power savings of up to 65% over a standard LP system are demonstrated by the proposed architecture.
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Salehi, Amin, and Morteza Montazeri-GH. "Design and HIL-based verification of the fuel control unit for a gas turbine engine." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, no. 8 (March 17, 2020): 1460–70. http://dx.doi.org/10.1177/0954410020910593.
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The correct operation of a gas turbine engine depends on the accurate and stable performance of fuel control system and its components such as fuel control unit. Fuel control unit is an electro-hydraulic actuator of fuel control system whose function is to supply, regulate and send the fuel to the engine according to the electronic control unit command. In this paper, a new fuel control unit has been developed based on the load sensing concept for a turboshaft gas turbine engine. In the designed fuel control unit, the fuel flow rate is controlled by adjusting the fuel pressure. A NARX model and ANFIS controller is employed to design the pressure controller. A hardware in the loop framework, comprising of hydraulic circuit, sensors, data acquisition card and computers, is developed to evaluate the performance of the fuel control unit alongside the real-time simulation of other component such as engine and electronic control unit. Moreover, the consumed power by the fuel control unit is evaluated and a considerable improvement is indicated compared to typical fuel control units.
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Hruntovich, Mikolay, Deniz Moroz, Alexey Panfilov, Yegor Zhuk, and Ekaterina Mikhailova. "Vibration Diagnostics of Power Equipment Before Commissioning." E3S Web of Conferences 178 (2020): 01031. http://dx.doi.org/10.1051/e3sconf/202017801031.
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The article describes how to use vibration diagnostics to detect defects in the installation of new equipment and to determine the quality of repairs based on vibroacoustic characteristics. Especially relevant is the vibration diagnostics of rolling bearings before installation on the mechanism. If there are errors in the calculations of the magnetic system of synchronous generators, vibration occurs, which is not eliminated during operation. Design errors, poor assembly of pumping units, asynchronous motors, power transformers cause increased vibration, which leads to damage to the specified equipment. The main reasons causing the vibration of the transformer tank are considered and the frequency range from 50 to 6000 Hz is determined on which these defects can occur. Full-scale experiments of the vibration of the transformer tank have shown that certain defects can occur in a narrow frequency band. The practical application vibration diagnostics of the pump unit describes in this article. Technical diagnosis of pumping units of the sewer station was carried out for various included composition. The results obtained made it possible to exclude reverse hydraulic impacts as a possible cause of the failure of the pump unit.
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Yang, Chun Xia, Meng Tian Lu, Yuan Zheng, Xiao Qing Tian, and Yu Quan Zhang. "Inlet Passage’s Development and Optimization of New Tidal Unit-Shaft Tubular Turbine." Applied Mechanics and Materials 607 (July 2014): 312–16. http://dx.doi.org/10.4028/www.scientific.net/amm.607.312.
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A new type of tidal unit-vertical shaft tubular turbine is designed with high efficiency, large flow rate and low water head ,which has large power under the 2~3 meters water head. According to the data of the being installed tidal units and principles of tubular turbine’s design, the high efficiency vertical shaft tubular turbine was designed under large discharge and low head, which was suitable for the tidal power station. The design also considered the requirements of turbine’s size and the details of flow through the whole flow passage were attained. The turbine’s property was predicted by the 3-d numerical simulation software on the whole flow passage. Moreover, the influences of vertical shaft’s sizes were analyzed. And the terminal of vertical shaft with or without transverse brace and longitudinal brace were analyzed to get the influence. Considering the hydraulic performance of various methods, the best guide vane opening was chosen. The results show that, the turbine unit has the best performance on efficiency, hydraulic loss, etc. with the guide vane opening 62°, meeting the power station’s design requirements. The results show that the optimal designed flow passage’s efficiency reaches up to 88.4%, the flow rate becomes much larger and the power reaches 174.63kW. Without partial vortex, the flow pattern is smooth through the whole passage also with lower hydraulic loss.
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Wang, Huan, Dongye Sun, and Datong Qin. "A new continuously variable transmission system applied to transmission system of the roadheader's cutting unit." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, no. 19 (May 12, 2016): 3590–600. http://dx.doi.org/10.1177/0954406216649404.
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For the existing roadheader, the transmission system of the cutting unit cannot regulate speed and the cutting motor may break down because of the impact vibration. In this study, the power reflux hydraulic transmission system, which is a new continuous variable transmission system, is put forward to ameliorate these problems. The basic characteristics such as the speed ratio, efficiency and torque ratio are analysed on the basis of expounding the basic structure and operational principle of the power reflux hydraulic transmission system. The dynamic model of the transmission system of the cutting unit is established. The pulse signal is used as the simulation of the loads, when the roadheader suddenly encounters the high strength rock. Then the torsional vibration characteristics of the existing roadheader and the roadheader that is equipped with the power reflux hydraulic transmission system are analysed. The contrastive simulation results show that the motor and transmission system vibration of the roadheader which is equipped with the power reflux hydraulic transmission system is markedly attenuated relative to the existing roadheader. So the power reflux hydraulic transmission system can protect the cutting unit's motor and the transmission system.
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Yao, Kai, Yang Li, and Ke Li Xing. "Design of the Power Unit in the Hydraulic Hybrid Vehicle." Advanced Materials Research 655-657 (January 2013): 117–22. http://dx.doi.org/10.4028/www.scientific.net/amr.655-657.117.
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In order to reduce the energy consumption and the hydraulic noise, the paper modifies the hydraulic pump/motor and designs a novel high-speed filling valve for the system, which is normally open and large-diameter. The modified pump/motor and the valve constitute the power unit. In the ANSYS/FLUENT the paper simulates numerically the flow field in the high-speed filling valve. By the use of ANSYS/LS-DYNA the paper analyzes the impact stress of the valve core. According to the simulation results, the power unit is optimized. Tests show that the noise decreases significantly in the vehicle utilizing the valve.
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Zhu, Qing, Gang Liu, and De Chao Song. "The Study of Dynamic Characteristic of Full Hydraulic Power Steering System Based on AMESim." Advanced Materials Research 482-484 (February 2012): 474–77. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.474.
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The simulation model of full hydraulic power steering system whose key part is full hydraulic power steering unit is established based on AMESim. According to the parameters from one articulated construction vehicle, the dynamic characteristic of the full hydraulic power steering system can be studied. Through the input from steering wheel and external load in different situations, the response curve is obtained, that can provide references for the design of full hydraulic power steering system in articulated construction vehicles.
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Cai, Bao Ping, Yong Hong Liu, Yan Ting Zhang, Jiang Tao Ma, Yun Wei Zhang, Yu Juan Zhuang, Pei Wei Lu, and Yu Gui Luo. "Development of Test System for Subsea Tree Equipment." Applied Mechanics and Materials 440 (October 2013): 222–27. http://dx.doi.org/10.4028/www.scientific.net/amm.440.222.
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A test system for subsea tree equipment is developed for tree function testing after repair. The test system mainly consists of hydraulic unit and electric unit. The hydraulic unit is developed by revamping an old hydraulic power unit, which consist of six components, including reservoir, flush/fill pump circuit, high pressure hydraulic pump circuits, accumulator group, hydraulic supply circuits and fluid return circuit. The electric unit for subsea tree is developed by using NI Compact DAQ system, In order to control the hydraulic unit and acquire the pressure signals easily. The test procedures for flowloops, valve, and hydrostatic hydraulic pressure cycling are proposed based on the factory acceptance testing of subsea tree. A test for a repaired subsea tree is performed by using the developed test system. The results show that the repaired subsea tree is good enough after repair, and verify that the developed test system works well.
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TIKKANEN, Researcher Seppo, and Professor Matti VILENIUS. "HYDRAULIC FREE PISTON ENGINE-THE POWER UNIT OF THE FUTURE?" Proceedings of the JFPS International Symposium on Fluid Power 1999, no. 4 (1999): 297–302. http://dx.doi.org/10.5739/isfp.1999.297.
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Yan, Xiaopeng, and Baijin Chen. "Energy-Efficiency Improvement and Processing Performance Optimization of Forging Hydraulic Presses Based on an Energy-Saving Buffer System." Applied Sciences 10, no. 17 (August 31, 2020): 6020. http://dx.doi.org/10.3390/app10176020.
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This paper proposes an energy-saving system based on a prefill system and a buffer system to improve the energy efficiency and the processing performance of hydraulic presses. Saving energy by integrating such systems into the cooling system of a hydraulic press has not been previously reported. A prefill system, powered by the power unit of the cooling system, is used to supply power simultaneously with the traditional power unit during the pressurization stage, thus reducing the usage of pumps and installed power of the hydraulic press. In contrast to the traditional prefill system, the proposed energy-saving system is controlled by a servo valve to adjust flow according to the load profile. In addition, a buffer system is employed to the cooling system to absorb the hydraulic shock generated at the unloading stage, store those shares of hydraulic energy as a recovery accumulator, and then release this energy to power the prefill system and the hydraulic actuator in the subsequent productive process. Finally, through a series of comparative experiments, it was preliminarily validated that the proposed system could reduce the installed power and pressure shock by up to 22.85% and 41%, respectively, increase energy efficiency by up to 26.71%, and provide the same processing characteristics and properties as the traditional hydraulic press.
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Ageev, Sergey O. "DRAIN REGULATION OF LOW-HEADED HYDRAULIC UNIT." Russian Journal of Water Transport, no. 62 (March 10, 2020): 135–44. http://dx.doi.org/10.37890/jwt.vi62.44.
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The article considers possible problems for shipping, which may arise after the construction and commissioning of the Nizhny Novgorod low-pressure hydroelectric complex. By analyzing the available data on the change in navigation expenses through the Nizhny Novgorod hydroelectric power station and the predicted calculation of the water regime in the alignment of the created Nizhny Novgorod low-pressure hydroelectric system, it is ascertained in the article whether the navigable dimensions in depth are ensured in the section above and below the alignment of the NNSU during the navigation period. In order to determine the possibility of regulating runoff on a spillway of the Nizhny Novgorod State University, an experiment is set up at the Volga State Unversity of Water Transport laboratory, during which the speed and time parameters of the water flow are established. The article presents the results of the work.
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Liu, Wei, Hang Shan Gao, and Zhu Feng Yue. "Dynamic Reliability Evaluation of Pressure Pulsation for Hydraulic Power Pipelines." Advanced Materials Research 139-141 (October 2010): 2436–39. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.2436.
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The pressure pulsations inner the hydraulic power pipelines not only deteriorate the precision of execution unit, but also bring on vibration, noise or other troubles in hydraulic device. In this paper, the output pressure pulsations were treaded as a stationary random process approximately. The mean square deviation of dynamic stress under the pumping source white noise exciting was calculated based on frequency responses. The first-passage failure criterion and fatigue damage accumulation failure criterion were adopted to analyze the dynamic pressure reliability respectively, and the relation of amplitude pulsations and the pipelines reliability was obtained. The results indicated that the preventative design method of below10% of rated pressure did not meet the security specification of the hydraulic power unit.
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Zhang, Chunyou, Liang Wang, Hong Li, and Lihua Wang. "Experimental Research on Parameters of a Late-Model Hydraulic-Electromotor Hybrid Pumping Unit." Mathematical Problems in Engineering 2020 (May 15, 2020): 1–17. http://dx.doi.org/10.1155/2020/2923154.
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Beam pumping unit is widely applied in the oilfield area. However, the falling process of the pumping unit horsehead causes large-amplitude variations of the motor torque and greatly reduces the efficiency of the system. This paper proposes a late-model hydraulic-electromotor hybrid system which can realize energy recovery and assist electromotor work. The hybrid system can improve the matching characteristics between the electromotor and the pumping unit. A mathematical model is built and verified by experiment studies. According to the experimental and simulation results, it can be concluded that energy recovery function of the designed hydraulic-electromotor hybrid system is demonstrated to be effective, and the electromotor can keep the output power stable. As the efficiency of the hybrid power system affects the energy-saving effect, this paper establishes the efficiency model of the system and studies the key parameters affecting the efficiency of the system through experiments and simulation. The key parameters include the minimum displacement ratio of the pump and hydraulic motor, working pressure, and transmission ratio. This paper proposes a parameter optimization design method of the hydraulic-electromotor hybrid system. Under the optimal parameter combination, the hydraulic-electromotor hybrid system efficiency can reach 92%, and the electric power transmission efficiency of the system can be raised to 75%.
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Wei, Jiafu, Hao Wang, Yuanchu Cheng, and Xinran Guo. "Dynamics Analysis for Hydroturbine Regulating System Based on Matrix Model." Mathematical Problems in Engineering 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/3565296.
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The hydraulic turbine model is the key factor which affects the analysis precision of the hydraulic turbine governing system. This paper discusses the basic principle of the hydraulic turbine matrix model and gives two methods to realize. Using the characteristic matrix to describe unit flow and torque and their relationship with the opening and unit speed, it can accurately represent the nonlinear characteristics of the turbine, effectively improve the convergence of simulation process, and meet the needs of high precision real-time simulation of power system. Through the simulation of a number of power stations, it indicates that, by analyzing the dynamic process of the hydraulic turbine regulating with 5-order matrix model, the calculation results and field test data will have good consistency, and it can better meet the needs of power system dynamic simulation.
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Pilipenko, S. S., and A. P. Potapenkov. "Development and research of hydraulic drive of sheet shears." Izvestiya. Ferrous Metallurgy 62, no. 8 (September 13, 2019): 632–38. http://dx.doi.org/10.17073/0368-0797-2019-8-631-638.
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The paper describes the pump gear-multiplier drive of sheet shears with a two-cylinder power unit. The description of the developed drive scheme with the use of dual dispensers (reducer and multiplier) of periodic action is given. The gear is engaged at idle, the multiplier – at work. Their charging comes up at the reverse course of the power unit. Each dispenser has an input cylinder connected to the pump and two dosing (output) cylinders connected separately with the power cylinders of the power unit. In this case, the cylinder bodies form a fixed block, and the plungers (pistons) – a movable block. It solves the main task: synchronization of movement of the pistons (plungers) of the power cylinders during all operation periods. Due to different ratio of the area of pistons (plungers) of inlet (Fв ) and dosing cylinders (2Fд ), a direct stroke mode with two stages of pump speed and pressure is provided. For the reducer, ratio (Fв /(2Fд )) determines reduction coefficient (Kp < 1), for the multiplier – the coefficient of multiplication (Kм > 1). As a result, the idling speed of the pistons of the power cylinders and pressure developed by the pumps increase, and during the working stroke – these values decrease. Working pressure of the pumps is equalized at a direct flow at a reduced level, which determines reduction of their installation power (up to 30 %). The analysis of graphs of power loading and speed was made. The condition of constant load at each of three main periods of the drive operation was accepted as: idle, working and reverse. Determinant parameters of the considered drive are the coefficients Kр (reduction), Kм (animation) and Kс – the gain of the power unit. The paper presents a comparative analysis of the considered and simple pump drive in order to establish the received combination and range of these values.
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Lyashkov, V. I., S. I. Simanenkov, and V. V. Potapochkin. "Hydraulic scanning of a plate unit." Chemical and Petroleum Engineering 35, no. 3 (March 1999): 130–36. http://dx.doi.org/10.1007/bf02368192.
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Cho, Buyoun, Min-Su Kim, Sung-Woo Kim, Seunghoon Shin, Yeseong Jeong, Jun-Ho Oh, and Hae-Won Park. "Design of a Compact Embedded Hydraulic Power Unit for Bipedal Robots." IEEE Robotics and Automation Letters 6, no. 2 (April 2021): 3631–38. http://dx.doi.org/10.1109/lra.2021.3061390.
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Cao, You Hui, Jin Liu, Li Fu Shao, Fei Liu, and Wen Qun Xu. "Intelligent Driver Designing for Electro-Hydraulic Proportional Valve of Engineering Machine." Advanced Materials Research 562-564 (August 2012): 1108–12. http://dx.doi.org/10.4028/www.scientific.net/amr.562-564.1108.
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Intelligent driver based on C8051F500 and TLE7242-2G for electro-hydraulic proportional valve was designed in this paper. The driver has CAN interface, and can drive four channel electro-hydraulic proportional valves. The system scheme, power unit, MCU unit, drive unit and software were analyzed in detail. At last the system performance was simulated with MATLAB. The Intelligent driver is suit for modern engineering machine’s control system, which demands networking and distributed control.
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Jusoh, Mohd Afifi, Mohd Zamri Ibrahim, Muhamad Zalani Daud, Zulkifli Mohd Yusop, and Aliashim Albani. "An Estimation of Hydraulic Power Take-off Unit Parameters for Wave Energy Converter Device Using Non-Evolutionary NLPQL and Evolutionary GA Approaches." Energies 14, no. 1 (December 25, 2020): 79. http://dx.doi.org/10.3390/en14010079.
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This study is concerned with the application of two major kinds of optimisation algorithms on the hydraulic power take-off (HPTO) model for the wave energy converters (WECs). In general, the HPTO unit’s performance depends on the configuration of its parameters such as hydraulic cylinder size, hydraulic accumulator capacity and pre-charge pressure and hydraulic motor displacement. Conventionally, the optimal parameters of the HPTO unit need to be manually estimated by repeating setting the parameters’ values during the simulation process. However, such an estimation method can easily be exposed to human error and would subsequently result in an inaccurate selection of HPTO parameters for WECs. Therefore, an effective approach of using the non-evolutionary Non-Linear Programming by Quadratic Lagrangian (NLPQL) and evolutionary Genetic Algorithm (GA) algorithms for determining the optimal HPTO parameters was explored in the present study. A simulation–optimisation of the HPTO model was performed in the MATLAB/Simulink environment. A complete WECs model was built using Simscape Fluids toolbox in MATLAB/Simulink. The actual specifications of hydraulic components from the manufacturer were used during the simulation study. The simulation results showed that the performance of optimal HPTO units optimised by NLPQL and GA approaches have significantly improved up to 96% and 97%, respectively, in regular wave conditions. The results also showed that both optimal HPTO units were capable of generating electricity up to 62% and 77%, respectively, of their rated capacity in irregular wave circumstances.
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Liao, Shengli, Hongye Zhao, Gang Li, and Benxi Liu. "Short-Term Load Dispatching Method for a Diversion Hydropower Plant with Multiple Turbines in One Tunnel Using a Two-Stage Model." Energies 12, no. 8 (April 18, 2019): 1476. http://dx.doi.org/10.3390/en12081476.
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Short-term load dispatching (STLD) for a hydropower plant with multiple turbines in one tunnel (HPMTT) refers to determining when to startup or shutdown the units of different tunnels and scheduling the online units of each tunnel to obtain optimal load dispatch while simultaneously meeting the hydraulic and electric system constraints. Modeling and solving the STLD for a HPMTT is extremely difficult due to mutual interference between units and complications of the hydraulic head calculation. Considering the complexity of the hydraulic connections between multiple power units in one tunnel, a two-phase decomposition approach for subproblems of unit-commit (UC) and optimal load dispatch (OLD) is described and a two-stage model (TSM) is adopted in this paper. In the first stage, an on/off model for the units considering duration constraints is established, and the on/off status of the units and tunnels is determined using a heuristic searching method and a progressive optimal algorithm. In the second stage, a load distribution model is established and solved using dynamic programming for optimal load distribution under the premise of the on/off status of the tunnel and units in the first stage. The proposed method is verified using the load distribution problem for the Tianshengqiao-II reservoir (TSQII) in dry season under different typical load rates. The results meet the practical operation requirements and demonstrate the practicability of the proposed method.
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Dindorf, Ryszard, and Piotr Woś. "Development of energy efficient hydrostatic drives with energy recovery." Mechanik 90, no. 8-9 (September 11, 2017): 776–82. http://dx.doi.org/10.17814/mechanik.2017.8-9.114.
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Recovery of kinetic energy for its subsequent storage in hydraulic accumulators may be performed due to employment of regenerative braking. It is due to two-directional energy flow that the whole cycle of vehicle movement is made possible. Dynamic models, simulation results, and experimental tests of a electro-hydraulic hydrostatic systems with secondary control are presented, which can be used in hydraulic hybrid powertrains. Selection of control parameters of the secondary unit has the decidedly key meaning for improvement of efficiency of the hydraulic hybrid drives. Today’s hydrostatic drives can handle much more power per unit mass than electric machines, which implies a considerable advantage of series hydraulic hybrids.
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Ochkur, Galina. "DYNAMIC CHARACTERISTICS CALCULATION FOR ELECTRO-HYDRAULIC CONVERTER OF NOZZLE-FLAP TYPE FOR MODERNIZATION OF SYSTEM FOR MOTOR-CAR FUEL FEEDING CONTROL." Bulletin of Bryansk state technical university 2020, no. 5 (May 13, 2020): 32–38. http://dx.doi.org/10.30987/1999-8775-2020-5-32-38.
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At the current stage of the development of means for automatic control for the formation of qualitative systems of machines, construction and road machinery, railway transport there are used electro-hydraulic devices transforming electric input signals into hydraulic output power. To carry out a generalized analysis and for the fulfillment of the preliminary synthesis of an automated hydraulic system on the whole the static and dynamic characteristics of its separate units should be obtained.
In the paper there is presented a calculation of a theoretical dynamic characteristic of the electro-hydraulic nozzle-flap converter to substantiate potentialities of its inclusion as an adjusting device acting upon rods of a high-pressure fuel pump in the system of fuel feeding control of a KamAZ motor-car engine. At that the converter was considered as interconnected units: a unit of feedback. The methods of the investigation of processes in the converter are based on the fundamentals of the theory of automatic control.
As it follows from the transition function diagram obtained as a result of the investigations carried out the transition time of a electro-hydraulic converter slide valve movement from a neutral position into an extreme one in the course of sending a maximum control signal to the coil does not exceed 1.1 sec, that is satisfactory for the formation of hydraulic drive control systems.
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Wu, Bi Ying, Ning Tang, and Shui Guang Tong. "The Study Summarize of Computational Method on Transition Process in Hydropower Units." Applied Mechanics and Materials 457-458 (October 2013): 1531–37. http://dx.doi.org/10.4028/www.scientific.net/amm.457-458.1531.
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In the operation of the hydropower units, it often come across condition changes such as start-up, normal stop, increase or decrease the load and load rejection. This will cause the hydraulic transient process of the water power generation system, which is of great significance to the safe and stable operation of hydropower station. This paper analyzes the method to calculate the transient process of hydropower unit and expounds the principle of all kinds of calculation methods and steps to lay a foundation for further optimization study.
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Guo, Xiao Lin, Jia Ping Pan, Wei Sun, and Gan Chen. "Design and Entity Modeling of Wet Double Clutch." Advanced Materials Research 490-495 (March 2012): 2409–13. http://dx.doi.org/10.4028/www.scientific.net/amr.490-495.2409.
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In this paper, we calculates the main parameters of a c-class car, choose the friction material, confirm the structural dimensions of pivotal components, acquires the friction power and heat capacity, and design three kinds of wet double clutch arranged radially with hydraulic driving unit, arranged longitudinally with hydraulic driving unit and arranged longitudinally with mechanical driving unit respectively according to the dimensions of interspaces. Finally, the entity modeling of each structure is established through the three-dimensional modeling software.
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Gezer, Dogan, Yiğit Taşcıoğlu, and Kutay Çelebioğlu. "Speed control of hydraulic turbines for grid synchronization using simple adaptive add-ons." Measurement and Control 51, no. 7-8 (July 4, 2018): 276–84. http://dx.doi.org/10.1177/0020294018786743.
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Background: Parameters of the hydroelectric power plant controllers are typically tuned at the nominal operating conditions such as nominal head and single unit operation. Water level variations in reservoir and/or tailwater, and the presence of other active units sharing the penstock are common disturbances to the nominal assumption. Methods: This article proposes two adaptive add-ons, namely gain scheduling and model reference adaptive control, to the existing speed controllers to improve grid synchronization performance when the site conditions are not nominal. The add-ons were designed and tested on a validated dynamic model of a power plant unit by using a software-in-the-loop simulation setup. An off-season scenario is simulated, in which the original controller of the unit cannot bring the turbine to synchronize with the grid due to low gross head. Then, the add-ons were implemented on-site and experiments were performed under similar conditions. The parameter sets used in gain scheduling for different operation bands are determined off-line with the help of operational experience. The model reference adaptive control add-on requires a reference model and a learning rate. A description of the turbine speed-up profile at nominal operating conditions is sufficient to be used as the reference model. The proposed piecewise linear reference model favors stability over speed in settling to the nominal speed. Results: It is experimentally shown that the proposed add-ons compensate the negative effect of head loss in grid synchronization, and perform similar to the ideal performance at the nominal head. Conclusion: Both add-ons can be implemented on the available off-the-shelf speed governor controllers. They are suitable for use in all hydroelectric power plants, especially in unmanned ones, for automatic synchronization with less waste water.