scholarly journals Challenges and Solutions for High-Speed Aviation Piston Pumps: A Review

Aerospace ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 392
Author(s):  
Chenchen Zhang ◽  
Chenhang Zhu ◽  
Bin Meng ◽  
Sheng Li
Keyword(s):  
High Speed ◽  
Sliding Friction ◽  
Friction Pair ◽  
Weight Ratio ◽  
Operating Conditions ◽  
Piston Pump ◽  
Aviation Industry ◽  
Hydraulic Systems ◽  
Working Pressure ◽  
Axial Piston

As a core power component, aviation piston pumps are widely used in aircraft hydraulic systems. The piston pump’s power-to-weight ratio is extremely crucial in the aviation industry, and the “ceiling effect” of the PV value (product of compressive stress and linear velocity) limits the piston pump’s ability to increase working pressure. Therefore, increasing the piston pump’s speed has been a real breakthrough in terms of further enhancing the power-to-weight ratio. However, the piston pump’s design faces several challenges under the extreme operating conditions at high speeds. This study reviews several problems aviation axial piston pumps face under high-speed operating conditions, including friction loss, cavitation, cylinder overturning, flow pressure pulsation, and noise. It provides a detailed description of the research state of the art of these problems and potential solutions. The axial piston pump’s inherent sliding friction pair, according to the report, considerably restricts further increasing of its speed and power-to-weight ratio. With its mature technology and deep research base, the axial piston pump will continue to dominate the aviation pumps. Furthermore, breaking the limitation of the sliding friction pair on speed and power density, thus innovating a novel structure of the piston pump, is also crucial. Therefore, this study also elaborates on the working principle and development process of the two-dimensional (2D) piston pump, which is a representative of current high-speed pump structure innovation.

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.

Study on the Influence of Deformation of the Slipper of Axial Piston Pump under High Pressure on Oil Film Structure

2014 ◽  
Vol 900 ◽  
pp. 734-737 ◽  
Author(s):  
Huai Chao Wu ◽  
Yun Liu Yu
Keyword(s):  
High Pressure ◽  
Film Structure ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Working Pressure ◽  
Element Analysis ◽  
Oil Film ◽  
The Finite Element Analysis ◽  
Order Of Magnitude ◽  
Axial Piston

The stress and strain of the slipper of 35 MPa high pressure axial piston pump are analyzed by the finite element analysis method, and the following facts are revealed: in spite of the fact that the slipper can satisfy the use requirement in the aspect of stress, whereas, in the aspect of strain, the deformation of the bottom of the slipper increases with the pressure increase, and the deformation of the slipper has reached the order of magnitude of the oil film thickness under 35 MPa working pressure. Therefore, when the slipper pair of 35 MPa high pressure axial piston pump is designed and its oil film performances are studied, the influence of deformation of the slipper on the oil film structure must be considered comprehensively. The results of this study can provide some guides for developing 35 MPa high pressure axial piston pump.

scholarly journals Experimental Study on the Skidding Damage of a Cylindrical Roller Bearing

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4075 ◽  
Author(s):  
Qing Zhang ◽  
Jun Luo ◽  
Xiang-yu Xie ◽  
Jin Xu ◽  
Zhen-huan Ye
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Failure Modes ◽  
Roller Bearing ◽  
Weight Ratio ◽  
Operating Conditions ◽  
Roller Bearings ◽  
Light Load ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

As large-scale rotating machines develop toward high rotating speed and high power–weight ratio, skidding damage has become one of the major initial failure modes of cylindrical roller bearings. Therefore, understanding the skidding damage law is an effective way to ensure the safety of machines supported by cylindrical roller bearings. To realize the skidding damage, a high-speed rolling bearing test rig that can simulate the actual operating conditions of aviation bearings was used in this paper, and the skidding damage dynamic behaviors of cylindrical roller bearings were investigated. In addition, to ensure the accuracy of the obtained skidding damage mechanism, the cylindrical roller bearing was carefully inspected by microscopic analysis when the skidding damage occurred. Out results show that instantaneous increases in friction torque, vibration acceleration, and temperature are clearly observed when the skidding damage occurs in the cylindrical roller bearing. Furthermore, under the conditions of inadequate lubrication and light load, the critical speed of skidding damage is rather low. The major wear mechanisms of skidding damage include oxidation wear, abrasive wear, and delamination wear. The white layers are found locally in the inner ring and rollers under the actions of friction heat and shear force.

scholarly journals Research on Control Methods for the Pressure Continuous Regulation Electrohydraulic Proportional Axial Piston Pump of an Aircraft Hydraulic System

2019 ◽  
Vol 9 (7) ◽  
pp. 1376
Author(s):  
Peng Zhang ◽  
Yunhua Li
Keyword(s):  
Feedback Linearization ◽  
Control Method ◽  
Linear Quadratic Regulator ◽  
Piston Pump ◽  
Control Methods ◽  
Hydraulic Systems ◽  
Axial Piston Pump ◽  
Linear Quadratic ◽  
Delivery Pressure ◽  
Axial Piston

The objective of this paper is to design a pump that can match its delivery pressure to the aircraft load. Axial piston pumps used in airborne hydraulic systems are required to work in a constant pressure mode setting based on the highest pressure required by the aircraft load. However, the time using the highest pressure working mode is very short, which leads to a lot of overflow lose. This study is motivated by this fact. Pressure continuous regulation electrohydraulic proportional axial piston pump is realized by combining a dual-pressure piston pump with electro-hydraulic proportional technology, realizing the match between the delivery pressure of the pump and the aircraft load. The mathematical model is established and its dynamic characteristics are analyzed. The control methods such as a proportional integral derivative (PID) control method, linear quadratic regulator (LQR) based on a feedback linearization method and a backstepping sliding control method are designed for this nonlinear system. It can be seen from the result of simulation experiments that the requirements of pressure control with a pump are reached and the capacity of resisting disturbance of the system is strong.

Research on the Dynamics and Variable Characteristics of a Double-Swash-Plate Hydraulic Axial Piston Pump With Port Valves

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Pengcheng Qian ◽  
Zengqi Ji ◽  
Bihai Zhu
Keyword(s):  
Rotational Speed ◽  
Flow Distribution ◽  
Variable Method ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Working Pressure ◽  
Swash Plate ◽  
Working Principle ◽  
Hydraulic Axial Piston Pump ◽  
Axial Piston

Axial piston pumps with port valves are widely used in applications that require high pressure and high power. In the present research, a new type of double-swash-plate hydraulic axial piston pump (DSPHAPP) with port valves is presented. The structure and working principle of the pump are discussed, and the balance characteristics of the pump are analyzed. A mathematical model of the pump flow distribution mechanism considering the leakage is established, based on which the effects of centrifugal forces acting on the port valves, working pressure, and rotational speed on the flow distribution characteristics are studied. A new method of varying the displacement of the pump that changes the phase relation of the two swash plates is proposed, and the principle and regulating characteristics of the variable method are studied. A detailed analysis of the forces and moments acting on the cylinder and the bearing reaction forces is presented. Finally, the relationship between volumetric efficiency and working pressure, and rotational speed and variable angle, is presented. It is revealed through an analysis that the working principle of the pump is feasible, and that the variable method can meet the requirements of varying the displacement of the pump. The characteristics of static balance and dynamic balance of the double-swashplate pump have the advantage of reducing vibration and noise. The research results also show that the reasonable matching of the working pressure and rotational speed can increase the pump's working performance to its optimum level.

Power Loss of Slipper within Axial Piston Pump

2015 ◽  
Vol 779 ◽  
pp. 3-12
Author(s):  
Ze Bo Wang ◽  
Ji Hai Jiang ◽  
Yi Sun
Keyword(s):  
Power Loss ◽  
Friction Pair ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Factors Affecting ◽  
Friction Power ◽  
Swash Plate ◽  
Model Of Friction ◽  
Friction Surfaces ◽  
Axial Piston

The pair between slipper and swash-plate is an important friction pair in the axial piston pump. Due to quick relative velocity, alternating load, numerous slippers, and high contact pressure between the friction surfaces, the wear-out and fatigue failure constantly occurs, which is one of the key factors affecting reliability of the piston pump. It is of fundamental significance to investigate the mechanism of slipper power loss and to find an appropriate method to improve the lubrication of the slipper. Here, the model of friction power loss between slipper and swash-plate is established, and the friction power loss between slipper and swash-plate is solved and comparatively analysed. Finally, the correctness of theoretical analysis and simulation results are verified by experiments.

Development of Oil Hydraulic Components Using a Flow Visualization Technique

2012 ◽  
Vol 6 (4) ◽  
pp. 410-417 ◽  
Author(s):  
Tetsuhiro Tsukiji ◽  
◽  
Eishin Noguchi ◽  
Futoshi Yoshida ◽  
Keyword(s):  
High Speed ◽  
Video Camera ◽  
Ball Valve ◽  
Piston Pump ◽  
X Rays ◽  
Axial Piston Pump ◽  
Visualization Technique ◽  
High Speed Video ◽  
High Speed Video Camera ◽  
Axial Piston

In the present study, we succeed in observing cavitating flow near a notch (V-shaped groove) in a valve plate in an axial piston pump, and we improve an oil hydraulic ball valve, using the visualization technique. Our model of the axial piston pump, is designed to allow the jet flow near the notch and the cavitation cloud to be observed clearly from two directions using a high-speed video camera. Computational Fluid Dynamics (CFD) is employed to estimate the occurrence and the region of the cavitation cloud. It is found that our CFD method is very useful for estimating the region of the cavitation cloud. It is further found that adding notches serves to greatly reduce the cavitation region. Using a commercially available digital video camera, a high-speed video camera, and X-rays source, we also succeed in improving an oil hydraulic ball valve by preventing vibration, cavitation, and the noise.

New Swash Plate Damping Model for Hydraulic Axial-Piston Pump

1999 ◽  
Vol 123 (3) ◽  
pp. 463-470 ◽  
Author(s):  
X. Zhang ◽  
J. Cho ◽  
S. S. Nair ◽  
N. D. Manring
Keyword(s):  
Open Loop ◽  
Operating Conditions ◽  
Reduced Order Model ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Order Model ◽  
Nonlinear Simulation ◽  
Reduced Order ◽  
Swash Plate ◽  
Axial Piston

A new, open-loop, reduced order model is proposed for the swash plate dynamics of an axial piston pump. The difference from previous reduced order models is the modeling of a damping mechanism not reported previously in the literature. An analytical expression for the damping mechanism is derived. The proposed reduced order model is validated by comparing with a complete nonlinear simulation of the pump dynamics over the entire range of operating conditions.

scholarly journals The Efficiency of Mobile Hydraulic System with Diesel Engine and Axial Piston Pump Analysis

2021 ◽  
Vol 9 ◽  
Author(s):  
Murat Kapsiz ◽  
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Power Unit ◽  
Hydraulic System ◽  
Co2 Emission ◽  
Power Loss ◽  
Piston Pump ◽  
Hydraulic Systems ◽  
Axial Piston Pump ◽  
Axial Piston

Hydraulic systems are used in a wide variety of applications, stationary as well as mobile. Hydraulic pumps und motors are in many cases used for both propulsion and various work functions and is thus often a significant user of energy. Efficiency performance of a mobile hydraulic systems over a wide range of pressure and speed conditions is crucially important for power unit to save energy. In this study, efficiency of a mobile hydraulic system are studied. Mobile hydraulic system is equipped with diesel engine as power unit and axial piston pumps used for hydraulic power. The relationships between the efficiency of the axial piston pump and the power loss, the efficiency of diesel engine and the output power were explained by graphics. The average power loss of axial piston pump have changed from 0.1 kW to 2.5 kW. Losses of an axial piston pump have been determined thus fuel consumption and CO2 emission caused by these losses were shown by graph. The CO2 emission affected by the increase in pressure and speed, it reached from 5.231 kg/h to 5.61 kg/h. The research focused on analysis for axial piston pump in mobile applications, with emphasis on pump losses, fuel consumption and CO2 emission.

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