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Numerical investigation of external radiation noise induced by dipole and quadrupole sources in an axial piston pump

Extensive research has been performed on the reduction of flow ripple and pressure fluctuation in axial piston pumps. However, the acoustic characteristics and sound sources of the external radiation noise induced by the fluid within an axial piston pump body have been rarely studied. In this study, a hybrid method combining computational fluid dynamics (CFD) with computational acoustics (CA) based on the Lighthill's acoustic analogy (LAA) theory was adopted to calculate the external radiation noise. First, a three-dimensional unsteady flow field was calculated by using CFD model, and the consistency between the computed results and experimental test data was verified. Then, the quadrupole and dipole sound sources were obtained based on the LAA theory. After that, the finite element method (FEM) was adopted to numerically analyze the natural modes of the axial piston pump shell, and it had been verified by the experimental modal test. Finally, the external radiation noise induced by the different fluid sound sources was calculated based on FEM/AML (automatically matched layer) vibro-acoustic coupling method. The results show that the quadrupole sound source is the main contributor of external radiation noise. Subsequently, the effects of different triangular groove structural parameters on external radiation noise were studied. This research can provide guidance for engineers in the design of low noise axial piston pumps.