Research on Cavitation of Valve Plate Groove for the High Pressure Axial Piston Pump

To guide the optimization design and explore the cavitation mechanism in the groove of the valve plate in a high-pressure axial piston. A cavitation numerical model is established based on the flow characteristics in the groove, and a visualization experiment is carried out using a high-speed camera. Subsequently, a numerical simulation model including a single piston cavity and a valve plate fluid domain is established. The cavitation of the valve plate under high pressure is simulated. The mechanisms of jet-flow cavitation and vortex cavitation are investigated, and the evolution of vortices and cavitation at different rotation angles is analyzed. An optimized valve plate is proposed. Finally, comparative tests are conducted on the complete pump to evaluate the performance of the original and optimized valve plates. The results indicate that the cavitation model simulations and visual experiments show good agreement. A high-velocity jet area is formed when the oil passes through the groove. The jet area becomes longer, and the jet angle becomes smaller when the opening is half. At the high-velocity jet-flow and vortices in the grooves of the valve plate, the pressure drops below the saturated vapor pressure of the hydraulic oil, thereby inducing jet cavitation and vortex cavitation. The vortices gradually expand and become more flattened in shape as the piston chamber rotation angle increases, while the vortex core on the lower side of the jet-flow region progressively shifts downstream. The cavitation region exhibits a similar evolution trend to that of the jet-flow and vortices structures. The optimized valve plate reduces cavitation, decreasing vapor volume fraction by 53.43%. Pressure pulsation and noise level are reduced by 76.19% and 4.8 dB(A) at 2000 r/min and 20 MPa, respectively.