Flow characteristics of a trochoidal-gear pump using bond graphs and experimental measurement. Part 2

The present paper describes an extensive study of trochoidal-gear pumps. As described in part 1 of the current paper, geometry and kinematics of trochoidal profiles and volumetric characteristics were considered to different extents. The bond graph technique was applied to model a trochoidal-gear pump based upon an ideal representation in order to simulate the instantaneous flow where the intricate aspects of leakage had been deliberately left aside. Nevertheless, leakage and interaction of the flow inside the pump are now presented in Part 2. The bond graph technique is applied to model a trochoidal-gear pump based upon a real representation in order to simulate the instantaneous flow, taking into account the different types of leakage by modelling them. Results from simulation of both models are compared and significant conclusions are obtained. The paper also examines the experimental determination of the flow ripple. A convenient method of experimentally measuring the so-called 'secondary source' method is applied, as described in part 1. Results are verified by using two different test rigs to predict the flow ripple of a crankshaft mounted gerotor pump for the lubrication of IC engines. Results show good qualitative agreement with bond graph models. Correlation is shown to be good under certain parameters. There are two ultimate goals: to validate the bond graph model with the experimental results for the determination of the instantaneous flow and to compare and contrast the source flow ripple results processed by two different mathematical algorithms by using two test rigs. In this way, this new investigation of the flow characteristics through simulation and experiment is a step to reach the dynamic properties of trochoidal-gear pumps under realistic conditions for use in further studies for modelling more complex hydraulic components.