Numerical Analysis of the Water Film Characteristics in the Eccentric State of a Radial Piston Pump

This paper investigates the working efficiency and reliability of a piston pair of radial piston pumps by accurately calculating the shape and pressure distribution of the piston pair. First, a leakage model of the piston pair is established based on the equivalent liquid resistance and adaptive eccentricity. This model considers the piston micro-motion in the cylinder and the force balance. Then, the piston clearance shape and pressure distribution are numerically simulated using a genetic algorithm and the finite-volume method, and the clearance leakage flow is discussed. The example analysis demonstrates the accuracy of the model; the iterative algorithm has good numerical stability at the given precision and can rapidly converge to the global optimal solution of the model to obtain the real-time piston eccentricity state and pressure distribution with high accuracy. The results demonstrate that the model has high accuracy. Finally, the effects of various parameters such as the piston diameter, initial clearance of the piston pairs, and piston speed on the leakage rate are discussed. The conclusions of this paper provide guidance for the design of water piston pumps.