流体激励下泵喷推进器声振耦合响应数值分析

泵喷推进器由导管、转子和定子组成,它具有推进效率高的优势,但其在流体的作用下也易产生剧烈的结构振动并辐射噪声,削弱水下舰船的声隐身性能。为了解流体激励下泵喷推进器的动态特性,首先通过基于大涡模拟的计算流体力学(CFD)仿真计算,得到推进器的非稳态流场,提取泵喷推进器关键结构表面的脉动压力,并将此流体载荷作为推进器声振耦合分析的激励源;然后,建立泵喷推进器水下结构声振耦合系统的有限元/边界元模型,分析流体激励下结构的振动位移响应和辐射声场分布;最后,讨论不同进速系数对于泵喷推进器水动力性能和声振耦合响应的影响。仿真分析的结果可以为典型结构泵喷推进器的减振降噪设计提供一定的依据。

Flow-induced Vibro-acoustic Coupling Response Analysis of Pump Jet Thrusters

The pump jet thruster, which is composed of the duct, rotors and stators, helps improve the propulsion efficiency of an underwater ship, yet excessive vibrations would occur due to hydraulic excitations, and the radiated noise will weaken the acoustic stealth performance of the ships. In order to understand the dynamic characteristics of pump jet thruster under fluid excitation, a computational fluid dynamics (CFD) with large eddy simulation (LES) is conducted in this paper firstly, and the fluctuating pressure on the interior surface of the duct is obtained, which is transformed into structural excitations; then, a coupled finite element/boundary element model (FEM/BEM), which consists of the duct and the surrounding water, is established. Based on this model, the vibration displacement of the duct and radiated sound pressure field under the structural excitations are calculated and analyzed. Moreover, the influences of the advanced coefficient on the hydrodynamic properties and vibro-acoustic responses are also presented. The simulations in this paper provide a guideline for the vibration and noise reduction design of the propellers with a similar structure in engineering.