Study of Effect of Air Content in Lubrication Oil on Gerotor Pump Performance Using CFD Simulations

Fill speed and volumetric efficiency are two important performance characteristics for positive displacement pumps. Gerotor pump is a positive displacement internal type gear pump with a smaller inner rotor and an internal ring rotor. Dissolved air and entrained air content in the lubrication oil significantly affects the filling characteristics of suction chambers of the Gerotor pump. This leads to reduction in the pump flow rate and fill speed which limits maximum operating speed of the pump. In this paper, effect of dissolved air and entrained air is studied by modeling cavitation in detail using PumpLinx^® CFD software and the importance of these parameters on Gerotor pump performance is described. The simulated results are validated with experiments with more than 95% accuracy in predictions. Key takeaway of present work suggests that design engineers should take dissolved air and entrained air effects into consideration while designing a pump.