A numerical procedure to reduce the noise emitted by External Gear Pumps

External gear pumps offer very good performance at competitive costs, making them widely spread worldwide. On the other hand, these machines are generally characterized by high levels of vibrations and noise emissions. This article presents a numerical methodology based on lumped parameter approach to optimize both spur and helical External Gear Pumps (EGPs). The methodology was implemented in a multi-environment tool called EgeMATor MP+, developed by the Fluid Power Research Group of the Universities of Naples and Sannio. This tool executes a closed-loop procedure, which starts from the pump drawing. Thanks to several subroutines developed in different interconnected environments, it permits global analysis and later optimizes EGPs. A reference pump was optimized, acting on the geometry of the pressure relief grooves of the wear plate, with the objectives of reducing flow ripple fluctuations, pressure spikes, and crossflow. Finally, both reference and optimized pumps were tested in the CNR-STEMS research institute laboratory in Ferrara, using a specific test rig, which physically isolates the pump from the prime mover. Sound pressure levels were measured in several points surrounding each pump and the results showed an effective reduction of the emitted noise for the optimized design.