Experimental investigation of the effect of grooves cut over the piston surface on the volumetric efficiency of a radial hydraulic piston pump

A radial piston pump often used in high pressure applications. The geometry of the pistons used affects the mechanical and volumetric efficiency of the pump and its long term performance. In the present study, the effect of grooves cut on the piston surface, the number of the grooves and their location over the piston surface on the volumetric efficiency of the hydraulic radial piston pumps was investigated. In order to perform the research tests, the three-piston fixed displacement pump with seven configurations was firstly designed and fabricated. The output flow rate of the pump was determined at pressure outlets of 350 and 500 bar and then the volumetric efficiency was calculated as the mean values of measured data. The results showed that the grooves cut on the piston surface produces a higher piston–cylinder overall leakage and then tend to reduce the volumetric efficiency. Also as the number of grooves being cut on piston surface increases, an increase in leakage will happen. In addition, by increasing the outlet pressure from 350 to 500 bar, the volumetric efficiency decreased significantly for the pumps with higher number of grooves cut. Among the configurations studied, pump with one groove at the inner edge at second groove position is the one bringing the best performance because of the minimum reduction in the volumetric efficiency between grooved piston pumps and producing higher restoring torque at all pump configurations according to previous literature. © 2017 Informa UK Limited, trading as Taylor & Francis Group.