Numerical Modeling of Vane Oil Pump with Variable Displacement

The oil flow rate in an automotive vane pump varies by virtue of the eccentricity between the inner rotor and the chamber wall. The movement of the chamber wall is facilitated by a ring-spring assembly which is pivoted and moves depending on the balance of system oil pressure and the pre-tensioned spring. In this paper, the ODE of kinetics of the solid piece spring motion is dynamically coupled with CFD simulation of oil flow in a vane pump. A re-meshing step is taken at every time step based on the update of the fluid domain which is determined from the ring position. The algorithm is implemented in the general purpose CFD code PumpLinx and applied to an automotive vane oil pump. The simulation results of pump performance curve are compared with the measurement data, together with the ring positions comparison. A very good agreement is observed between the simulation results and measurement data. The work demonstrates the efficiency and effectiveness of the present approach as there is very little overhead of incorporating the dynamics of solid motion into the CFD model. The process of setting up the model from CAD geometry to CFD simulation will be discussed in detail.