Analysis of Noise Characteristics of Pump Injection Propeller

With the development of acoustic detection technology, the requirements for acoustic concealment of underwater vehicles have become increasingly stringent, attracting significant attention to pump-jet thrusters as the primary noise source of underwater vehicles. Therefore, this paper takes a novel pump-jet thruster as the research object. Firstly, based on the feasibility of numerical validation using the standard model P4119, the flow characteristics of the pump-jet thruster are calculated to determine its optimal operating conditions. Subsequently, using the steady flow field results corresponding to the optimal operating conditions as initial values, the pump-jet thruster is subjected to noise analysis calculations using finite element/infinite element Lighthill acoustic analogy theory and the FW-H time domain equation. The results show that, from the perspective of the sound pressure level spectrum, the stator components of the pump-jet thruster exhibit obvious line spectrum characteristics at their blade-passing frequency and its harmonics. Regarding the nine sets of monitoring points set up, the closer they are to the stator, the higher the noise sound pressure level, and the sound pressure level decreases with increasing distance. The sound pressure attenuation characteristics of the nine sets of monitoring points remain consistent. Based on the power spectrum of simulated pump-jet noise, it is concluded that pump-jet noise is a wideband noise composed of low-frequency narrowband line spectra and high-frequency broadband continuous spectra. These research findings provide a theoretical basis for designing low-noise propellers and have important guiding significance for improving the overall performance of underwater vehicles.