scholarly journals A New Approach for Modeling Mixed Lubricated Piston-Cylinder Pairs of Variable Lengths in Swash-Plate Axial Piston Pumps

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5836
Author(s):  
Bo Zhao ◽  
Xinqing Hu ◽  
Haifeng Li ◽  
Yonghui Liu ◽  
Baocheng Zhang ◽  
...  
Keyword(s):  
Multibody Dynamics ◽  
Tilt Angle ◽  
Piston Pump ◽  
Dynamics Model ◽  
Axial Piston Pumps ◽  
Piston Cylinder ◽  
Cylinder Length ◽  
Swash Plate ◽  
Axial Piston ◽  
Multibody Dynamics Model

The swash-plate axial piston pump is one of the most widely used pumps due to its simplicity and compactness in structure. In such a pump, the piston-cylinder system plays a crucial role, with its lubrication characteristics greatly affecting the overall pumping performance. A new numerical approach is proposed in this study for modeling mixed lubricated piston-cylinder interfaces of variable lengths in swash-plate axial piston pumps in the framework of multibody dynamics. The approach couples the hydrodynamic mixed lubrication model of the piston-cylinder interface with the multibody dynamics model of the piston pump. The lubrication model is established with a transient average Reynolds equation considering asperity contacts and is solved with the finite element method to derive the hydrodynamic forces of the lubricated pair, while the multibody dynamics model is established with Lagrangian formalism by considering hydrodynamic forces as external forces. Results for piston-cylinder interfaces of variable lengths in swash-plate axial piston pumps are presented, and the impacts of cylinder length and the tilt angle of the swash plate on the tribological performances of the interface are discussed. The results indicate that increasing the cylinder length can improve the stability and wear resistance of the piston, but it can exacerbate the frictional power loss. Moreover, although enlarging the tilt angle of the swash plate can effectively increase pump displacement, it can easily lead to serious friction, wear, and leakage problems. Consequently, the tilt angle of the swash plate should be carefully selected in practical applications.

scholarly journals A Numerical Study on Influence of Temperature on Lubricant Film Characteristics of the Piston/Cylinder Interface in Axial Piston Pumps

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1842 ◽  
Author(s):  
Yueheng Song ◽  
Jiming Ma ◽  
Shengkui Zeng
Keyword(s):  
Thermal Effect ◽  
Contact Time ◽  
Numerical Study ◽  
Lubricant Film ◽  
Piston Pump ◽  
Pump Efficiency ◽  
Axial Piston Pumps ◽  
Piston Cylinder ◽  
Film Characteristics ◽  
Axial Piston

The loss of kinetic energy of moving parts due to viscous friction of lubricant causes the reduction of piston pump efficiency. The viscosity of lubricant film is mainly affected by the thermal effect. In order to improve energy efficiency of piston pump, this research presents a numerical method to analyze the lubricant film characteristics in axial piston pumps, considering the thermal effect by the coupled multi-disciplinary model, which includes the fluid flow field expressed by Reynolds equation, temperature field expressed by energy equation and heat transfer equation, kinematics expressed by the motion equation. The velocity and temperature distributions of the gap flow of piston/cylinder interface in steady state are firstly numerically computed. Then the distributions are validated by the experiment. Finally, by changing the thermal boundary condition, the influence of thermal effect on the lubricant film, the eccentricity and the contact time between the piston and cylinder are analyzed. Results show that with the increase of temperature, the contact time increases in the form of a hyperbolic tangent function, which will reduce the efficiency of the axial piston pump. There is a critical temperature beyond which the contact time will increase rapidly, thus this temperature is the considered as a key point for the temperature design.

The Influence of Cross Angle on the Flow Ripple of Axial Piston Pumps by CFD Simulation

2012 ◽  
Vol 220-223 ◽  
pp. 1675-1678 ◽  
Author(s):  
Xiu Ye Wei ◽  
Hai Yan Wang
Keyword(s):  
Noise Reduction ◽  
Cfd Simulation ◽  
Rotation Angle ◽  
Piston Pump ◽  
Flow Pulsation ◽  
Flow Ripple ◽  
Axial Piston Pumps ◽  
Swash Plate ◽  
The Cross ◽  
Axial Piston

This paper studies the flow pulsation of axial piston pumps of different cross angles based on CFD simulation. The swash-plate cross angle of piston pump affects the piston pump outlet flow pulsation by changing the contraction amount of the plunger in the valve plate transition zone. First, we established the flow pulsation model with swash plate cross angle based on the noise reduction principle of the swash plate cross angle, and studied the influence of cross angle of different rotation angels on the flow pulsation based on CFD simulation. The conclusion is that the maximum and minimum peak of the flow pulsation decreased when the rotation angle of the cross angle is greater than 1 °; the maximum and minimum peak of the flow pulsation increased when the rotation angle of the cross angle is less than -1 °; a good noise reduction can be got when the piston pump cross angle rotates 1°.

scholarly journals Multibody Dynamics Model and Simulation for the Totally Enclosed Lifeboat Lowered From Ship in Rough Seas

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 32171-32187
Author(s):  
Shaoyang Qiu ◽  
Hongxiang Ren ◽  
Haijiang Li ◽  
Yi Zhou ◽  
Delong Wang
Keyword(s):  
Multibody Dynamics ◽  
Dynamics Model ◽  
Model And Simulation ◽  
Multibody Dynamics Model

Improving the Volumetric Efficiency of the Axial Piston Pump

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Shu Wang
Keyword(s):  
Operating Conditions ◽  
Volumetric Efficiency ◽  
Valve Plate ◽  
Piston Pump ◽  
Efficient Design ◽  
Axial Piston Pumps ◽  
Definition Of ◽  
Engineering Practices ◽  
First Time ◽  
Axial Piston

The volumetric efficiency is one of the most important aspects of system performance in the design of axial piston pumps. From the standpoint of engineering practices, the geometric complexities of the valve plate (VP) and its multiple interactions with pump dynamics pose difficult obstacles for optimization of the design. This research uses the significant concept of pressure carryover to develop the mathematical relationship between the geometry of the valve plate and the volumetric efficiency of the piston pump. For the first time, the resulting expression presents the theoretical considerations of the fluid operating conditions, the efficiency of axial piston pumps, and the valve plate designs. New terminology, such as discrepancy of pressure carryover (DPC) and carryover cross-porting (CoCp), is introduced to explain the fundamental principles. The important results derived from this study can provide clear recommendations for the definition of the geometries required to achieve an efficient design, especially for the valve plate timings. The theoretical results are validated by simulations and experiments conducted by testing multiple valve plates under various operating conditions.

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