间隙动态变化下泵喷推进器非定常力数值分析

Numerical analysis on unsteady forces of a pump-jet propulsor under dynamic tip-clearance changes

  • 摘要:
    目的 旨在研究转子间隙动态变化对泵喷推进器非定常力的影响。
    方法 采用重叠网格,构建SUBOFF潜艇带泵喷推进器的数值计算模型,并结合SST k-ω 湍流模型,针对转子垂向振动的频率靠近转子叶频的工况进行数值计算。
    结果 结果显示,受间隙动态变化的影响,转子和导管的三向激励力的频率与幅值均发生了变化,且转子和导管的垂向激励力在三向激励力中占优;而转子和导管表面的脉动激励会在新的分支频率处出现峰值。
    结论 由柔性隔振系统导致的转子间隙动态变化对泵喷推进器的激励源特性有重要影响,所做研究对柔性隔振系统与泵喷推进器之间的匹配设计具有指导意义。

     

    Abstract:
    Objectives This study aims to investigate the impact of dynamic variations in rotor tip-clearance on the unsteady forces of a pump-jet propulsor and analyze the role of a flexible isolation system in influencing the excitation characteristics of the propulsion system. The findings contribute to optimizing propulsion system design and enhancing submarine stealth performance.
    Methods An overset grid technique is used to construct a numerical model of the SUBOFF submarine with a pump-jet propulsor, coupled with the SST k-ω turbulence model for simulations. Numerical calculations are performed for operating conditions where the rotor's vertical vibration frequency approaches the rotor blade passing frequency. Frequency spectrum analysis is conducted to assess the effects of dynamic tip-clearance variations on fluctuating pressure and excitation forces.
    Results The results indicate that dynamic tip-clearance variations significantly affect the three-directional (x, y, z) excitation forces of the rotor and duct, with the vertical excitation force exhibiting the highest amplitude, followed by the lateral and axial forces. Moreover, pulsating pressure on the surface of the rotor peaks appear at new branch frequencies, particularly at RF (rotor vibration frequency) and BPF (blade passing frequency). The lateral and vertical excitation forces of the duct are more strongly influenced by tip-clearance variations compared to those of the rotor.
    Conclusions The dynamic changes in rotor tip-clearance induced by the flexible isolation system have a significant impact on the unsteady force characteristics of the pump-jet propulsor. The findings provide valuable guidance for optimizing the compatibility between the flexible isolation system and the pump-jet propulsor, contributing to submarine noise reduction and improved stealth performance.

     

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