Influence of Slip Boundary Condition on Oil Film Flow Between Piston and Cylinder

doi:10.3901/JME.2018.20.152

Abstract

Abstract: In the swash plate-type axial piston pump, the relative motion of piston/cylinder is lubricated and the fluid in the displacement chamber is sealed by the oil film between piston and cylinder. The characteristics of piston/cylinder is influenced by the oil film directly and significant to design and optimize the piston/cylinder. According to the periodic rule of piston motion, the shear stress and flow rate of oil film under different slip lengths and rotational speeds of pump in a period of work are analyzed by the kinetic equation, which is built on the Navier-Stokes(N-S) equations and the Navier-slip boundary condition. During the suction phase, it is shown that the shear stress near the piston wall reduces but the flow rate increases with the increasing slip length. The shear stress decreases about 18% and flow rate increases about 13.59% when slip length increases from 1 μm to 3 μm at the maximum velocity of piston. During the pumping phase, the larger velocity of piston results in the smaller difference of the shear stress near the piston wall and the flow rate between the slip condition and no-slip condition. Comparing with the no-slip condition, the shear stress reduces obviously and the gap of total flow rate also decreases when the slip length is 1 μm and the rotational speed of pump increases from 1 500 r/min to 4 000 r/min.

Key words: navier-slip boundary, oil film flow, piston and cylinder, shear stress

CLC Number:

O357

LIU Zhaomiao, YU Jianwei, ZHENG Huilong, ZHANG Tan, KANG Zhenya. Influence of Slip Boundary Condition on Oil Film Flow Between Piston and Cylinder[J]. Journal of Mechanical Engineering, 2018, 54(20): 152-158.

References

[1] MATTEO P, MONIKA I. Heat transfer and thermal elastic deformation analysis on the piston/cylinder interface of axial piston machines[J]. Journal of Tribology Transactions of the ASME, 2012, 134(4):119-128.
[2] UWE W, MONIKA I. Computer aided optimization of bearing and sealing gaps in hydrostatic machines-The simulation tool Caspar[J]. International Journal of Fluid Power, 2002, 3(1):7-20.
[3] MONIKA I, ROLF L. An investigation into micro-and macro geometric design of piston/cylinder assembly of swash plate machines[J]. International Journal of Fluid Power, 2004, 5(1):23-36.
[4] BIBOULET N, LUBRECHT A A. Analytical solution for textured piston ring-Cylinder liner contacts (1D analysis)[J]. Tribology International, 2016, 96:269-278.
[5] KUMAR S, BERGADA J M. The effect of piston grooves performance in an axial piston pumps via CFD analysis[J]. International Journal of Mechanical Sciences, 2013, 66:168-179.
[6] PETER A T, SANDRA M T. A general boundary condition for liquid flow at solid surfaces[J]. Nature, 1997, 389(6649):360-362.
[7] GH M M, LI D Q. Flow characteristics of water in microtubes[J]. International Journal of Heat and Fluid Flow, 1999, 20(2):142-148.
[8] RICHARD F S, ALICIA E F. Numerical analysis of a slider bearing with a heterogeneous slip/no-slip surface[J]. Tribology Transactions, 2004, 47(3):328-334.
[9] HUI Z, MENG H, GUANG N D. Boundary slip surface design for high speed water lubricated journal bearings[J]. Tribology International, 2014, 79(11):32-41.
[10] 刘赵淼, 王国斌, 申峰. 基于Navier滑移的油膜缝隙微流动特性数值分析[J]. 机械工程学报, 2011, 47(21):104-110. LIU Zhaomiao, WANG Guobin, SHEN Feng. Numerical analysis of oil film flow in micro gap with Navier slip boundary conditions[J]. Journal of Mechanical Engineering, 2011, 47(21):104-110.
[11] FATU A, MASPEYROT P, HAJJAM M. Wall slip effects in (elasto) hydrodynamic journal bearings[J]. Tribology International, 2011, 44(7-8):868-877.
[12] TAUVIQIRRAHMAN M, ISMAIL R, JAMARI J. A study of surface texturing and boundary slip on improving the load support of lubricated parallel sliding contacts[J]. Acta Mechanica, 2013, 224(2):365-381.
[13] 李战华. 微流控芯片中的流体流动[M]. 北京:科学出版社,2012. LI Zhanhua. Fluid flows in microfluidic chip[M]. Beijing:Science press, 2012.
[14] MATTEO P, MONIKA I. A geometric multigrid solver for the piston-cylinder interface of axial piston machines[J]. Tribology Transactions, 2012, 55(2):163-174.
[15] JING D, BHUSHAN B. Boundary slip of superoleophilic, oleophobic, and superoleophobic surfaces immersed in deionized water, hexadecane, and ethylene glycol[J]. Langmuir, 2013, 29(47):14691-14700.
[16] CHO Y Y, CHENG K S. Design of slip boundary produced by a lotus structure applied to a hydrostatic bearing[J]. Tribology Letters, 2014, 55(1):55-64.