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External gear pumps are positive displacement devices which perform with excellent efficiencies over a wide load and speed range. This wide range of performance is primarily due to micron-level leakage gaps in such machines which prevent large leakages at increasing loads. The present paper details a novel approach implemented in the commercial CFD tool PumpLinx that can capture the details of the micron level gaps, and model such machines accurately. The steps in creation of the model from original CAD geometry are described. In particular, the CFD mesh is created using a specialized template structured meshing method within PumpLinx especially created for external gear pumps and motors. This makes process of mesh creation and flow solution through complicated geometries of a gear pump efficient and streamlined.

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.