Noise prediction of external gear pumps via multiphysics aero-fluid-structural simulations

Accurate predictions of the noise field emitted by an external gear pump are presented in this paper, making use of hybrid numerical-experimental integrated approaches together with some acceleration measurements on the external casing surface of the pump. The noise field radiated by the pump was computed by means of finite element vibroacoustic simulations involving the structural dynamic response as excitation boundary condition. As for some other previous papers published by the authors, a first two-steps approach was carried out consisting in a structural FEM (Finite Element Method) model linked to an acoustic BEM (Boundary Element Method) model. Moreover, acoustic numerical methods were investigated, as integrated fluid-structure coupling approaches, developed in a commercial software. Sound power calculations based on sound intensity measurements around the pump casing were performed for validation purposes. The comparisons between numerical and experimental results aimed at confirming the proposed hybrid methodologies. In this paper the implementation of a further multiphysics approach is illustrated. The method is based on using the external gear pump inner pressure distributions as output of a CFD (Computational Fluid Dynamics) analysis with the structural model of the gear pump to compute its structural vibrations. These are then coupled to the fluid within the vibro-acoustic model. The CFD results are obtained by using a dynamic mesh approach capable of achieving an effective transient simulation of the fluid flow development inside the volume. The code uses a k-? turbulence model capable of providing an accurate distribution of the relevant parameters at the boundaries of the pump. This CFD-FEM approach proves to be an efficient pump design tool by allowing an estimate of fluid power, structural and vibro-acoustics characteristics of the component starting from its CAD representation.