Influence of power fluid temperature in hydraulics on operating efficiency of hydraulic mining excavators

2020 ◽  
pp. 78-81
Author(s):  
A. E. Krivenko ◽  
◽  
Zhang Kuok Khanh ◽  
Keyword(s):  
Operating Conditions ◽  
Piston Pump ◽  
Open Pit ◽  
Fluid Temperature ◽  
Axial Piston Pump ◽  
Pump Flow ◽  
Hydraulic Mining ◽  
Hydraulic Excavators ◽  
The Republic ◽  
Axial Piston

The Republic of Vietnam has great mineral resources. Open pit mines use hydraulic excavators. In hot climate, the excavators lose capacity, and the number of the hydraulics failures grows. To identify the causes of unstable operation of the hydraulics, the authors analyze the capacity reduction factors, namely, hydraulic pump leaks. The test subject is pump HPV95 for Komatsu hydraulic excavators. The axial-piston pump leaks take place in clearances of control and injection gears, and only have mutable and cyclic behavior in the piston and cylinder clearances. This has an adverse effect on uniformity of the pump flow and on stability of the injection pressure. Generally, leaks can be evaluated from the Reynolds equation of fluid flow rate in the ring clearance. The input data are the design variables of axial-piston pump HPV95 and power fluid temperature range of Komatsu hydraulic mining excavators operated in open pit mining in the south in the Republic of Vietnam. Matlab-based Simulink modeling shows that with increasing temperature of power fluid, leaks in the injection gear grow nonlinearly in the absolute value and so does the surging amplitude in the pump flow. As a consequence, the pressure fluctuations and vibrations in the hydraulic gear elevate. The modeling also exhibits higher surge and reduced net capacity of the hydraulics with rising temperature of power fluid. These changes are caused by reduction in the flow friction in the ring channel between the piston and block of cylinders. Thus, the power fluid cooling system engineering subject to hydraulics capacity, operating conditions and cooling methods is highly critical for the efficient operation of hydraulic mining excavators.

Cavitation in a high-speed aviation axial piston pump over a wide range of fluid temperatures

2021 ◽  
pp. 095765092110469
Author(s):  
Qun Chao ◽  
Zi Xu ◽  
Jianfeng Tao ◽  
Chengliang Liu ◽  
Jiang Zhai
Keyword(s):  
Temperature Effects ◽  
Pressure Pulsation ◽  
Piston Pump ◽  
Limiting Factors ◽  
Fluid Temperature ◽  
Cfd Model ◽  
Axial Piston Pump ◽  
Wide Range ◽  
Fluid Properties ◽  
Axial Piston

The axial piston pump in aerospace applications needs to operate over a wide range of fluid temperatures from −54°C to 135 °C. The fluid properties at such extreme temperatures will significantly affect the cavitation that is one of the major limiting factors for the efficiency and reliability of aviation axial piston pumps. However, it appears that very little of the existing literature studies the effects of extreme fluid temperatures on the pump cavitation. This paper aims to examine the temperature effects on the cavitation in an aviation axial piston pump. First, we develop a three-dimensional (3D) transient computational fluid dynamics (CFD) model to investigate the pump cavitation and validate it experimentally. Second, we use the validated CFD model to investigate the temperature effects on the pump cavitation by changing the fluid properties including viscosity, density, and bulk modulus. The numerical results show that low fluid temperature makes the aviation axial piston pump suffer serious cavitation due to high viscosity, leading to delivery flow breakdown, unacceptable pressure pulsation, and delayed pressure built up. In contrast, high fluid temperatures have minor effects on the cavitation although they increase the pressure pulsation and built-up time slightly.

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.

Surface modification effects on lubricant temperature and floating valve plate motion in an axial piston pump

2019 ◽  
Vol 234 (1) ◽  
pp. 3-17 ◽  
Author(s):  
David Richardson ◽  
Farshid Sadeghi ◽  
Richard G Rateick ◽  
Scott Rowan
Keyword(s):  
Equations Of Motion ◽  
Surface Modifications ◽  
Analytical Investigation ◽  
Operating Conditions ◽  
Valve Plate ◽  
Piston Pump ◽  
Plate Motion ◽  
Cylinder Block ◽  
Axial Piston Pump ◽  
Axial Piston

The objectives of this study were to experimentally measure motion of a floating valve plate and analytically investigate the effects of floating valve plate surface modifications on the lubricant film thickness and temperature distribution. In order to achieve the experimental objectives, a previously developed axial piston pump test rig was instrumented with proximity probes to measure the motion of the valve plate. To achieve the objectives of the analytical investigation, the thermal Reynolds equation augmented with the Jakobsson-Floberg-Olsson (JFO) boundary condition and the energy equation were simultaneously solved to determine the pressure, cavitation regions, and temperature of the lubricant at the valve plate/cylinder block interface. The lubricating pressures were then coupled with the equations of motion of the floating valve plate to develop a dynamic lubrication model. The stiffness and damping coefficients of the floating valve plate system used in the dynamic lubrication model were determined using a parametric study. The elastic deformation of the valve plate was also considered using the influence matrix approach. The experimental and analytical motions of the valve plate were then corroborated and found to be in good agreement. Four- and eight-pocket designs were then added as surface modifications to the floating valve plate in the dynamic lubrication model. The addition of surface modifications on the valve plate resulted in increased minimum film thicknesses and lowered lubricant temperatures at the same operating conditions.

Effect analysis of silencing grooves on pressure and vibration characteristics of seawater axial piston pump

2016 ◽  
Vol 231 (8) ◽  
pp. 1390-1409 ◽  
Author(s):  
Fanglong Yin ◽  
Songlin Nie ◽  
Wei Hou ◽  
Shuhan Xiao
Keyword(s):  
Three Dimensional ◽  
Vibration Characteristics ◽  
Operating Conditions ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Effect Analysis ◽  
Compressibility Effect ◽  
Low Viscosity ◽  
Dynamics Simulations ◽  
Axial Piston

Seawater axial piston pump is a critical power component in seawater fluid power system. As the properties of high bulk modulus and low viscosity of seawater, the pressure and vibration characteristics of the seawater axial piston pump will be getting poorer than the traditional oil pump. In this study, the pressure, flow, and vibration characteristics for a seawater axial piston pump are investigated. The three-dimensional computational fluid dynamics simulations for the port plate with non-grooved, U-shaped, and triangle-based pyramid silencing groove designs have been conducted over a range of operating conditions, which consider the fluid compressibility effect and cavitation damage. Measurements of pressure ripple and pump vibration are carried out at various loading conditions to verify the results of simulation. The experiment turned out that the well-designed port plate can mitigate both pressure ripples as well as vibrations of the pump. This research will lay the foundation for the further development of a low fluid noise seawater axial piston pump.

Pressure, Flow, Force, and Torque Between the Barrel and Port Plate in an Axial Piston Pump

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
J. M. Bergada ◽  
J. Watton ◽  
S. Kumar
Keyword(s):  
Pressure Distribution ◽  
Operating Conditions ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Operating Characteristics ◽  
Double Peak ◽  
Fluctuation Pattern ◽  
Total Magnitude ◽  
Axial Piston ◽  
Insight Into

This paper analyzes the pressure distribution, leakage, force, and torque between the barrel and the port plate of an axial piston pump. A detailed set of new equations is developed, which takes into account important parameters such as tilt, clearance and rotational speed, and timing groove. The pressure distribution is derived for different operating conditions, together with a complementary numerical analysis of the original differential equations, specifically written for this application and used to validate the theoretical solutions. An excellent agreement between the two approaches is shown, allowing an explicit analytical insight into barrel/port plate operating characteristics, including consideration of cavitation. The overall mean force and torques over the barrel are evaluated and show that the torque over the XX axis is much smaller than the torque over the YY axis, as deduced from other nonexplicit simulation approaches. A detailed dynamic analysis is then studied, and it is shown that the torque fluctuation over the YY axis is typically 8% of the torque total magnitude. Of particular novelty is the prediction of a double peak in each torque fluctuation resulting from the more exact modeling of the piston/port plate/timing groove pressure distribution characteristic during motion. A comparison between the temporal torque fluctuation pattern and another work shows a good qualitative agreement. Experimental and analytical results for the present study demonstrate that barrel dynamics do contain a component primarily directed by the torque dynamics.

Mathematical Modeling of a Variable Displacement Axial Piston Pump

1999 ◽  
Author(s):  
Jeff W. Dobchuk ◽  
Richard T. Burton ◽  
Peter N. Nikiforuk ◽  
Paul R. Ukrainetz
Keyword(s):  
Mathematical Model ◽  
Operating Conditions ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Specific Effects ◽  
Lumped Parameter ◽  
Lumped Parameter Models ◽  
Wide Range ◽  
Variable Displacement ◽  
Axial Piston

Abstract The variable displacement axial piston pump has been the subject of much research, having been studied from the controls, noise reduction, and design perspectives. The resulting body of research is large and very diverse in content. A review of the available publications was conducted for this paper in order to identify those works that would be most helpful in developing a complete and accurate mathematical model of an axial piston pump. Most of the available publications can be classified into one of two general groups; those describing a small group of components to understand specific phenomena or those describing the entire pump for control or design purposes. The significant mathematical developments in various publications regarding specific phenomena, particularly those works involving nonlinear friction or pressure transients, were identified by the authors in this paper. When the mathematical developments of the phenomena specific effects are combined with the widely accepted kinematics equations for the pump, an accurate numerical model can be developed. Works on linearized lumped parameter models and parameter sensitivity were examined for this paper and the limitations of these types of models were addressed. While linearized models offer mathematical simplicity, they suffer from poor accuracy over a wide range of operating conditions and do not reflect instantaneous swashplate dynamics. This paper offers insight into the required complexity of a mathematical model that is necessary to achieve a desired accuracy as well as providing the appropriate references to develop that model.

Design of Swash Plate Axial Piston Pump Flow is Stable

2014 ◽  
Vol 912-914 ◽  
pp. 621-623
Author(s):  
Kai Jun Chen
Keyword(s):  
Uniform Flow ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Pump Flow ◽  
Swash Plate ◽  
Axial Piston

Marine auxiliaries in the pump is the largest number, the most species of ship equipment. The pump is non-uniform flow before.This paper designed several swash plate axial piston pump, in order to solve the problem of uneven.

Dynamic Analysis of an Axial Piston Pump Swashplate Control

1986 ◽  
Vol 200 (1) ◽  
pp. 49-58 ◽  
Author(s):  
G Zeiger ◽  
A Akers
Keyword(s):  
Control Volume ◽  
Damping Ratio ◽  
Low Frequency ◽  
Operating Conditions ◽  
Piston Pump ◽  
State Variables ◽  
Axial Piston Pump ◽  
Basic Parameters ◽  
Experimental Values ◽  
Axial Piston

A mathematical model of an axial piston pump is described which consists of a second-order differential equation of the swashplate motion and two first-order equations describing the flow continuity into the pump discharge chamber and into the swashplate control actuator. The equation of the swashplate angle contains torque components due to operating states. A method is presented by which the average torque can be computed for a pump of given geometry and at any given set of operating conditions. From the calculated average torque, the coefficients of the basic equation can be evaluated; agreement to within 10 per cent of experimental values for torque has been achieved. A state variables analysis of the dynamic behaviour has shown that there are two dominant poles at low frequency and that the damping ratio associated with these poles reduces by approximately one half when the downstream control volume increases by a factor of three, and varies from 0.84 to 0.48 as the pump rotational speed increases from 126 to 209 rad/s. It has been concluded that the assumption of linear variation with the basic parameters, which is a necessary prerequisite for the use of states variables analysis, is justified. The work outlined in this paper represents a step in the design process associated with the optimal control of an axial piston pump.

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