Abstract: The finite element calculation model of water axial piston pump is established by the mixture hybrid and RNG κ-ε turbulence model of the Fluent software. The plunger movement and cylinder rotary are simulated by the dynamic mesh and sliding mesh. The UDF (User Defined Function) is used to set the compressibility of the fluid. It is found that the cavitation degree of plunger cavity is strongly related to m value (the ratio of the diameter of the plunger cavity to the equivalent diameter of the cylinder kidney shape hole). The mathematical model of m_c without cavitation value is established. Simulation results shows thatn the smaller the m value is, the smaller the cavitation degree of the plunger cavity is. The bigger the angle β of the swash plate and the velocity ω of the cylinder block are, the smaller the un-cavitation area in the plunger cavity is. It is demonstrated that a reasonable choice of m value can reduce the cavitation of plunger cavity and vibration of the piston pump, improve the volumetric efficiency of axial piston pump, which has practical meaning for the design of axial piston pump.

Key words: water axial piston pump, cavitation, dynamic mesh, sliding mesh