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

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.

[1]  Monika Ivantysynova,et al.  Determination of Gap Surface Temperature Distribution in Axial Piston Machines , 2006 .

[2]  Toshiharu Kazama.  Thermohydrodynamic Lubrication Model Applicable to a Slipper of Swashplate Type Axial Piston Pumps and Motors (Effects of Operating Conditions) , 2010 .

[3]  Minel J. Braun,et al.  Cavitation formation and modelling for fluid film bearings: A review , 2010 .

[4]  Monika Ivantysynova,et al.  The Impact of Axial Piston Machines Mechanical Parts Constraint Conditions on The Thermo-Elastohydrodynamic Lubrication Analysis of The Fluid Film Interfaces , 2013 .

[5]  H. McCallion,et al.  The Analysis of Thermal Effects in a Full Journal Bearing , 1970 .

[6]  Hubertus Murrenhoff,et al.  Simulation of the Lubricating Film between Contoured Piston and Cylinder , 2010 .

[7]  Steve M. Rohde,et al.  A Thermoelastohydrodynamic Analysis of a Finite Slider Bearing , 1975 .

[8]  Michael M. Khonsari,et al.  On The Fluid-Solid Interaction in Reference to Thermoelastohydrodynamic Analysis of Journal Bearings , 1991 .

[9]  J. Frěne,et al.  A Study of the Thermohydrodynamic Performance of a Plain Journal Bearing Comparison Between Theory and Experiments , 1983 .

[10]  Monika Ivantysynova,et al.  A Novel Thermal Model for the Piston/Cylinder Interface of Piston Machines , 2009 .

[11]  Marco Zecchi,et al.  A novel fluid structure interaction and thermal model to predict the cylinder block / valve plate interface performance in swash plate type axial piston machines , 2013 .

[12]  Jintai Mi,et al.  THD Analysis of Rolling Piston and Journal Bearings in Rotary Compressors , 2016 .

[13]  Hulin Huang,et al.  A thermal-fluid coupling numerical study on the characteristics of air–oil two phase flow and heat transfer in a micro UAV bearing chamber , 2017 .

[14]  Jun Qu,et al.  Effect of oil temperature on tribological behavior of a lubricated steel−steel contact , 2015 .

[15]  Weixi Ji,et al.  A velocity-slip model for analysis of the fluid film in the cavitation region of a journal bearing , 2016 .

[16]  Lars Olems.  Investigations of the Temperature Behaviour of the Piston Cylinder Assembly in Axial Piston Pumps , 2000 .

[17]  Jiaxu Wang,et al.  Exploration on a Fast EHL Computing Technology for Analyzing Journal Bearings with Engineered Surface Textures , 2014 .

[18]  Jia Li,et al.  Wear analysis of swash plate/slipper pair of axis piston hydraulic pump , 2015 .