Computational fluid dynamics and particle image velocimetry assisted design tools for a new generation of trochoidal gear pumps

Abstract

Trochoidal gear pumps produce significant flow pulsations that result in pressure pulsations, which interact with the system where they are connected, shortening the life of both the pump and circuit components. And this behaviour is not acceptable for the demands of its current applications. The complicated aspects of the operation of a gerotor pump make computational fluid dynamics the proper tool for modeling and simulating its flow characteristics. Regarding the numerical simulation, a three-dimensional with deforming mesh Computational Fluid Dynamics (CFD) model is presented. The model includes the effects of the manufacturing tolerance and the leakage inside the pump. A new boundary condition is created for the simulation of the solid contact in the interteeth radial clearance. The experimental study of the pump is carried out by means of Time-Resolved Particle Image Velocimetry (TRPIV), and results are qualitatively evaluated thanks to the numerical simulation results. TRPIV is proved to be a feasible alternative to obtain the instantaneous flow of the pump in a direct mode. Thus, a new methodology involving CFD and TRPIV is presented, which allows the obtaining of the instantaneous flow of the pump in a direct mode without altering its behaviour significantly.