Propeller exciting force is divided into bearing force and surface force according to the transfer path, and they are essential for radiated noise of the underwater vehicle. Surface force is an increasingly important issue in radiated noise because of the appearance of guide vanes and ducts. But the related questions about surface force are not thoroughly considered.Here we show spectral characteristics of surface force and its formation mechanism.Computational Fluid Dynamics is used in this paper.&nbsp;One of the important results is that there is a significant blade passing frequency (BPF) line spectrum in the radial component of surface force，which does not appear in the axial direction; Another one is that the frequency amplitude at BPF of the duct is ten times that of the guide vanes, which shows that the duct mainly contributes to the surface force. We also found that the amplitude of the duct surface force is equivalent to the impeller bearing force, which illustrates the importance of surface force research. It is demonstrated that the tip leakage vortex is the reason for the duct surface force by the analysis of the flow field. By optimizing the span load distribution to control the tip leakage vortex, we effectively suppress the duct surface force.The result obtained by this study can be used to reduce the radiated noise of underwater vehicles.

Research on Formation Mechanism and Suppression Method of Surface Force Caused by Pump Jet Propeller

Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2021/volume/85284

ASME 2021 Fluids Engineering Division Summer Meeting (FEDSM2021)

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