Numerical modeling and experimental investigation of noise generation in external gear pumps

An external gear pump is taken as reference for a new model to understand the impact of the pressure ripple on the noise generation. The lumped parameter model HYGESim is adapted to provide the loading pressure functions as frequency spectra of the outlet pressure ripple which constitutes the fluid-borne noise. The fluid-borne noise is examined, and a standard external gear pump is compared to new prototype designs which reduce the outlet pressure ripple. Several experimental studies were completed which accomplished key tasks. The first study validated the pump model in terms of pressure ripple prediction through comparison to experimentally measured results for the standard and prototype pumps. The second study focused on the air-borne noise through sound pressure and intensity measurements on the reference and prototype pumps at fixed operating conditions. An additional set of measurements at a wide range of operating speeds and pressures was completed to explore the impact of operating condition to greater detail. A preliminary discussion on a coupled FEM/BEM model for predicting the noise generation of displacement machines is discussed. The described pump model results and experimental study allows for a greater understanding of the acoustic performance of external gear pumps with respect to the pressure ripple