Finite Element Integrated Methodologies Applied to External Gear Pump Vibroacoustic Analysis

Accurate predictions of the noise field emitted by an 8.5 cc/rev external gear pump are presented in this paper, making use of a hybrid numerical-experimental integrated approach together with some acceleration measurements on the gear pump external casing. FFT (Fast Fourier Transform) acceleration spectra were experimentally acquired (B&K Pulse system) in a few positions of the external gear pump casing for some operating conditions. A first two-step approach was carried out that consisted in analysing the harmonic response of the pump with a structural FEM (Finite Element Method) model, and then in computing the noise radiated field through vibroacoustic simulations by mapping the structural dynamic response as excitation boundary conditions to an acoustic BEM (Boundary Element Method) model. Sound power tests based on sound intensity measurements were performed for validation purposes. The comparisons between numerical and experimental results confirmed the potentiality of this approach in offering a good compromise between noise prediction accuracy and reduction of experimental and modelling requirements. A second integrated approach was investigated as an alternative and efficient strategy in the commercial software Simcenter 3D: a single model including the structural FEM representation of the gear pump as well as the surrounding acoustic mesh was used in conjunction with the FEMAO (FEM Adaptive Order) method, allowing to drastically reduce the modelling time and improve the computational performance, as compared with a classical FEM approach.