Abstract: The fluid-borne noise considers the dynamics of the fluid, i.e. flow ripple and pressure pulsation. It is obvious that most of noise in the piston pump comes from the fluid-borne noise, so many researchers pay attention on the theoretical analysis on pressure pulsations and experiment study on flow ripple. By summarizing the advantages and limitations of different groups’ study, suggestions and comments are given for further research efforts. A theoretical model of the pressure pulsations within piston chamber is produced, which accounts for the influence of oil condensability, port plate throttle effects, piston momentum, oil leakage, inertia character of oil within relief groove and cavitations. Also, a new kind of dynamic model is brought forward for future analyzing. Besides, the test principle for measuring the source flow ripple of piston pump is described. And seven classic test methods are listed and introduced. The structure and characters of an experiment system, such as pipeline, installation position and performance requirement of sensors, loading device, signal acquisition and analysis system, are explained. Finally, the future research direction and development trend of the fluid-borne noise are forecasted.

Key words: Axial piston pump, Flow ripple, Noise, Pressure pulsation