An integrated simplified approach to external gear pump noise field prediction

Harmonic response methods and vibroacoustic analysis are considered as tools of a methodology aimed at computation and prediction of the acoustic field emitted by a gear pump. In particular, FFT acceleration spectra were experimentally acquired only in few positions of a 8.5 cc/rev external gear pump case in different operating conditions and considered as external excitation boundary conditions to a FE quite simplified vibroacoustic model. The emitted noise field was computed considering the pump as a 'black box', without taking into account the complex dynamics of gear tooth meshing process and consequent fluid pressure/load distribution. Sound power tests as well as sound pressure measurements in some positions around the pump casing were performed for validation purposes. Furthermore the identification was investigated of the lowest number of FFT acceleration spectra which leads to an acceptable estimate of the noise field emitted by the pump. The potentiality of this approach was confirmed and a good compromise was found between noise prediction accuracy and reduction of experimental and modelling requirements.