Pressure characteristics of a novel double rotor hydraulic transformer

Jiang, Jihai; Liu, Zhongxun

doi:10.1177/0959651818822392

Cited by 4 publications

(5 citation statements)

References 20 publications

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“…Fig. 7 shows the test curves of p B from the proposed DRHT in this paper and the ''single rotor'' prototype test results in the literature [27], respectively. We can see that the value of p B increases rapidly as the control angle δ increases while decreases gradually with the increase of the rotational speed.…”

Section: Resultsmentioning

confidence: 99%

“…Compared with the existing structure, the main improvement of DRHT is that the setting of the valve plate control angle can be accomplished through a small force without the impacts of the axial torques, which enables fast response speed. However, as soon as the working parameters, such as the rotating speed and the valve plate control angle, are changed, the volume change rate of the plunger cavity changes accordingly [27]. Then the volume change effects acting on the transient pressure inside the plunger occur.…”

Section: Introductionmentioning

confidence: 99%

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The Experimental and CFD Research on the Pressure Reduction Process of the Double Rotor Hydraulic Transformer

Jiang

Liu

2019

IEEE Access

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Served as a core component, the performance of the hydraulic transformer (HT) directly affects the energy-saving performance of the common pressure rail (CPR) system. The pressure reduction process of HT is accompanied by an expansion of the plunger cavity, which can result in a steep pressure drop and lead to cavitation under certain working parameters. In order to enhance the performance, a double rotor hydraulic transformer (DRHT) is proposed, and systematic analysis of the pressure reduction process in DRHT is provided by the CFD simulation and experimental test. The CFD model is based on the dynamic mesh method considering both cavitation and turbulence. The experiment is carried on with a specially designed prototype and four kinds of valve plates. The results show that the transient pressure decreases sharply with increasing rotating speed, and minimum transient pressure is reached at the control angle of −30 degrees. The damping groove can deter the volume expansion effect and thus enlarging the working range, but the volume loss will be incurred. The results of the parameter study show that the damping groove with the length 4 mm and the depth 3 mm can avoid the excessively low transient pressure occur while maintaining low volume loss. The simulation curves have good consistency with the test results, which credit the numerical method feasible and effective. The current work is also significant for further design and the application of the DRHT.INDEX TERMS Hydraulic transformer, common pressure rail, energy saving, hydraulic systems, hydraulic equipment, pressure reduction process.The associate editor coordinating the review of this manuscript and approving it for publication was Tao Wang.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Experimental and CFD Research on the Pressure Reduction Process of the Double Rotor Hydraulic Transformer

Jiang

Liu

2019

IEEE Access

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“…Liu et al designed an electrohydraulic serve swash plate axial plunger-type transformer to change the pressure transformation ratio of a hydraulic transformer by controlling the oscillating motor [ 10 , 11 , 12 ]. To solve the problems of hydraulic transformers, including high fluctuation of output flow and pressure, inability to operate at low speed, and high noise, Liu et al proposed a novel configuration of hydraulic transformers with double rotors and discussed the influences of structural parameters (e.g., the wrap angle of the distribution slot and the number of plungers) and operating parameters (e.g., control angle and CPR pressure level) on the characteristics of a hydraulic transformer [ 13 , 14 ]. Yang et al proposed a variable hydraulic transformer for realizing the simultaneous control of load pressure and load flow of a new hydraulic transformer, effectively reducing noise and leakage and further improving the pressure transformation ratio [ 15 , 16 , 17 ].…”

Section: Introductionmentioning

confidence: 99%

Analysis of and Experimental Research on a Hydraulic Traction System Based on a Digital Hydraulic Transformer

Zhang

Liu

et al. 2022

Sensors

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In this study, we designed a new type of digital hydraulic transformer using four gear–pump/motor units with a displacement ratio of 20:21:22:23 and two control valve groups that consist of four solenoid directional valves. The driving gear shafts of the four gear–pump/motor units are fixedly connected to achieve synchronous rotation. The two control valve groups are respectively installed through an integrated valve block on the inlet and outlet of each gear–pump/motor unit. With the objective of reducing the installed power and energy consumption of hydraulic traction systems, we propose a new energy-saving hydraulic system based on a digital hydraulic transformer. This hydraulic system uses a digital hydraulic transformer as a pressure/flow control element. By controlling the power on/off states of eight solenoid directional valves, the digital hydraulic transformer can realize a change in output flow and then a change in speed of the hydraulic cylinder piston rod. Through the theoretical derivation and simulation analysis of the hydraulic system pressure/flow change process, and the experimental verification of the built hydraulic traction system based on the experimental platform, a conclusion is drawn that the proposed digital hydraulic transformer can change the output pressure/flow of a hydraulic system through a binary digital control, verifying the feasibility of the pressure change principle of the designed digital hydraulic transformer and the rationality of the hydraulic traction system circuit.

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“…At present, the research of IHT mainly focuses on pressure control problem 32 and efficiency problems, 33,34 insufficient research has been done on flow control problems. Because the inclined angle of the swash plate is fixed, the load pressure and the load flow of IHT are corresponding to each other, that is, the flow cannot be controlled under the fixed load pressure.…”

Section: Introductionmentioning

confidence: 99%

Four-port hydraulic transformer with inlet and outlet equal flow and its flow characteristics

Zhang

Zhou

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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Without changing the original valve control hydraulic system, a kind of hydraulic transformer, called four-port hydraulic transformer (FHT), is proposed to recover the energy loss caused by system throttling. The remarkable feature of FHT is that the flow rate at inlet and outlet ports are equal. This means that FHT can be connected into the load circuit of hydraulic system to recovery energy without refreshing flow rate. This paper investigates the flow characteristics of FHT, including instantaneous flow rates, average flow rates and flow pulsations in each port. The relationships between the structure of port plate and the flow characteristics are given. The variation rule of number of plungers connected to four ports is shown, and the relationship between the variation and the flow pulsation is revealed. The simulation results show that the flow rates and displacements of symmetrical ports are same, and the instantaneous flow rate of symmetrical ports has the same rule. The results also show the frequent changes of the number of plungers connected with each port lead to more flow jump points in instantaneous curves, and the jump point is the basic cause of its loud noise. The test shows that the flow rates of measurement data of the experiment are very close to the theoretical analysis, proved the theoretical analysis of flow characteristics for FHT are appropriate and reasonable, which has a certain reference for the development and energy-saving application for FHT.

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Pressure characteristics of a novel double rotor hydraulic transformer

Cited by 4 publications

References 20 publications

The Experimental and CFD Research on the Pressure Reduction Process of the Double Rotor Hydraulic Transformer

The Experimental and CFD Research on the Pressure Reduction Process of the Double Rotor Hydraulic Transformer

Analysis of and Experimental Research on a Hydraulic Traction System Based on a Digital Hydraulic Transformer

Four-port hydraulic transformer with inlet and outlet equal flow and its flow characteristics

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