A novel fluid structure interaction model for the grooved piston-cylinder interface in axial piston pump

Abstract

In the design of high pressure and high speed axial piston pump, grooves on piston are often used to improve the lubrication condition of piston-cylinder interface. However, the position and parameters of grooves are still depending on experience and experiment. A novel fluid structure interaction (FSI) model for the grooved piston-cylinder interface is formulated in this study, which aims to reveal the performance of oil film. Based on the kinematic analysis of piston, the instantaneous pressure of displacement chamber in piston pump is calculated. Reynolds equation is discretized and solved on the oil film mesh to obtain the pressure distribution of oil film. Eccentricities of piston center is iterated out with force balance loop. Influence method is used to calculate the deformation of both piston and cylinder. Six types of piston are introduced and compared in this study. Simulation results indicate that the grooves near displacement chamber can improve the trajectory of the micro motion of piston, which finally avoid contact between piston and cylinder and reduce viscous friction power loss. The grooves far from displacement chamber could store oil and reduce the leakage flow piston-cylinder interface.