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A numerical and experimental investigation of parametric effect on flow ripple

This paper presents a parametric study on flow ripple for guiding the design of a piston pump. For the purpose of minimizing flow ripple, a detailed simulation model is built. In this simulation model, a modified method for computing precisely leakage flow rate from the oil film between valve plate and cylinder block, the oil film between cylinder block and piston, and the oil film between the slipper and the swash plate is proposed. Then the influence of fluid characteristics, such as the fluid compressibility and viscosity and the air contained in the fluid, is taken into consideration in the simulation model. In addition, the motion of the piston, cylinder, and slipper is referenced in one simulation model making the simulation model closer to a real pump. Validated using test results obtained from the secondary source method, the computational accuracy with the modified simulation has been adequately improved for analyzing the parametric effects on flow ripple and optimizing the design of a piston pump. The findings conclude that for the same working conditions, the fluid compressibility has been identified to be the most significant cause responsible for flow ripple. The leakage flow rate and fluid viscosity play the next important roles on the generation of flow ripple as compared to the effects due to the piston movement. When there is no cavitation in the working conditions, the effect of the air contained in the fluid on flow ripple can be neglected.