Shaping the Piston–Cylinder Interfaces of Axial Piston Machines for Running in the High-Pressure Regime with Water as the Hydraulic Fluid

Ernst, Meike; Ivantysynova, Monika; Vacca, Andrea

doi:10.1177/09544062211068643

Cited by 6 publications

(4 citation statements)

References 18 publications

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“…The energy dissipation of the piston-cylinder pair is mainly composed of frictional losses and leakage losses (Fang and Shirakashi, 1995). As shown in Fig.…”

Section: Calculation Of the Energy Dissipation Characteristic Paramet...mentioning

confidence: 99%

An investigation into the micro-geometric tapered-shape surface design of the piston bore of a piston–cylinder interface in an axial piston motor

Liu

Zeng

et al. 2023

Mech. Sci.

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Abstract. In pursuit of design solutions that reduce energy loss and improve wear resistance for the piston–cylinder interface in an axial piston motor, a fluid-structure interaction numerical model and a new test rig of the friction force of the piston–cylinder pair are developed to achieve the analysis and design of the micro-geometric tapered-shape surface of a piston bore. The piston bore with the tapered-shape surface axial distribution length ratio of 49.44 % of the overall length is found to be the relatively optimized one. Furthermore, how the shaft speed, load pressure, and swash plate angle influence the performance of the two-type interface is analyzed. Numerical analysis results show that, compared with the traditional cylindrical piston bore design, the piston–cylinder interface with the optimized tapered-shape piston bore in the axial piston motor can achieve a significant reduction in leakage flow and friction force, and the experimental results are consistent with the simulation results.

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“…The energy dissipation of the piston-cylinder pair is mainly composed of frictional losses and leakage losses (Fang and Shirakashi, 1995). As shown in Fig.…”

Section: Calculation Of the Energy Dissipation Characteristic Paramet...mentioning

confidence: 99%

An investigation into the micro-geometric tapered-shape surface design of the piston bore of a piston–cylinder interface in an axial piston motor

Liu

Zeng

et al. 2023

Mech. Sci.

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“…The average speed is more than 3500 r/min, and some EHA pumps can even reach 22,500 r/min and the operating life can reach more than 20,000 h [15]. Vacca et al from Purdue University used the virtual prototype method to design the surface texture of the micro-surface contour of the pistoncylinder interface of the piston pump and studied the influence of the contour shape on the load under the high-pressure condition and concluded that the concave hole contour could best improve the overall load support under the high-pressure stroke [16]. Domestic research on the high speed of the bivariate axial piston pump is mainly carried out in colleges and universities.…”

Section: Introductionmentioning

confidence: 99%

Design and Characteristic Research on Variable Displacement Mechanism of Two-Dimensional (2D) Bivariable Pump

Xing,

Ji,

Yang

et al. 2024

Energies

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In a hydraulic system, a micro variable pump is required to be high pressure and high speed, and this work presents a new type of 2D bivariable pump structure in which the worm gear and worm mechanism are used to rotate the cylinder block to change the flow distribution state of the cylinder window and the piston groove to change the displacement of the 2D pump. The flow–pressure mathematical model of the 2D variable pump is established to analyze the relationship between pump displacement and the pump cylinder rotation angle and the effects of variable displacement on pump pressure characteristics, flow characteristics, and volume efficiency in Matlab. During the experiment, we tested the change in the corresponding pump output flow when the cylinder rotation angle is 0~12°, which verifies the correctness of the variable calculation model. The experimental results indicate that the volume efficiency and mechanical efficiency of the single-piston 2D pump are reduced to different degrees after variable displacement, the volume efficiency is reduced by approximately 3% at most, and the mechanical efficiency is reduced by approximately 5% at most.

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“…Typically, these machines operate with hydraulic oil as the working fluid. However, over the past few years, several researchers have demonstrated the use of water as the working fluid for these machines [1]- [3]. Using water as a working fluid has several advantages: it is sustainable, environmentally friendly, non-flammable, non-toxic, and acts as an effective coolant for the machine.…”

Section: Introductionmentioning

confidence: 99%

Numerical Model of Piston/Cylinder Interface With Consideration of Turbulence Effect for Water Hydraulics

Mukherjee,

Han,

Shang

et al. 2024

14th International Fluid Power Conference

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Axial piston machines find their use over a wide range of the power spectrum owing to their superior reliability, efficiency, and power density. They are also a key component in applications like reverse osmosis and firefighting wherein the working fluid is water. Utilizing low viscous fluid, such as water, as a working fluid poses challenges in designing the critical lubricating interfaces of the piston pumps. Specifically, low viscosity makes it difficult for the lubricating interfaces to provide sufficient bearing and sealing functions in challenging operating conditions. In order to maintain the lubricating interface performance in water hydraulic piston pumps, costly materials, and tight manufacturing tolerances are often utilized. To improve the efficiency and cost-effectiveness of these pumps, accurate numerical simulation tools that consider the fluid and structure interaction are needed to provide valuable insights into these lubricating interfaces. Although the Reynolds equation is a reliable method for determining the fluid pressure distribution in an oil-based piston pump, it assumes a laminar flow which may not be applicable to water piston machines. For example, in an inclined piston/cylinder interface of a water hydraulic pump, there may be regions in the film wherein the large gap height combined with the low viscosity of water induce turbulence effects. If the traditional Reynolds equation is used in such a scenario, it is likely to overestimate the leakage flow through the interface as it does not account for turbulence. Therefore, it is important to incorporate the effect of turbulence in the diffusive terms of the Reynolds equation to accurately describe the Poiseuille flow with high Reynolds numbers. The challenge is further compounded by the micromotion and deformation of the solid body, resulting in the unevenness of the gap height in the lubricating film. Therefore, the consideration of turbulence can only be applied regionally in such cases. The current study proposes a fluid-structure interaction model with the consideration of the localized turbulent effects. This modeling approach is applied to the piston/cylinder interface of an axial piston machine that uses water as the working fluid. The approach stems from the modification of the Poiseuille term to incorporate a function of the Reynolds number. The fluid dynamics considering the turbulence effect was validated against the solution of the Navier Stokes equation using commercial CFD software. The modified Reynold equation was implemented in an axial piston pump EHL model coupled with the multi-body dynamics. The simulation results from the novel pump model were compared to a measurement and the accuracy of the proposed model was found largely improved from the traditional laminar solution. The calculated flow rate was found to be 54.6% lower with the additional consideration of the turbulence effect in the studied case.

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Shaping the Piston–Cylinder Interfaces of Axial Piston Machines for Running in the High-Pressure Regime with Water as the Hydraulic Fluid

Cited by 6 publications

References 18 publications

An investigation into the micro-geometric tapered-shape surface design of the piston bore of a piston–cylinder interface in an axial piston motor

An investigation into the micro-geometric tapered-shape surface design of the piston bore of a piston–cylinder interface in an axial piston motor

Design and Characteristic Research on Variable Displacement Mechanism of Two-Dimensional (2D) Bivariable Pump

Numerical Model of Piston/Cylinder Interface With Consideration of Turbulence Effect for Water Hydraulics

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