具有特型桨尖旋翼悬停状态气动噪声的初步试验研究

The primary experiments on aeroacoustic of rotor with unconventional blade-tip in hover

开展悬停状态下的具有CLOR桨尖旋翼气动噪声试验研究。为进行噪声特性对比,共设计完成三副模型旋翼,分别为参考的矩形桨叶、常后掠桨尖的桨叶以及具有CLOR桨尖气动外形的桨叶。在外场环境下,进行这三副模型旋翼在不同转速、不同桨叶安装角条件下及不同观测点上的旋翼气动噪声测量实验,测量包括声压级大小、声压时间历程及声压级频谱等。根据试验结果,对比分析具有CLOR特型桨尖旋翼与矩形桨尖以及常后掠桨尖旋翼的悬停气动噪声特性,并借助于CFD方法,以模拟桨叶上的气动载荷分布特性,得出关于非常规气动外形桨尖对旋翼气动噪声特性的影响规律,并初步体现了CLOR桨尖旋翼具有良好的噪声特性。

The aeroacoustic experimental investigations for rotor with CLOR blade-tip in hover have been conducted. For comparison purpose, three types of model rotors have been designed, such as the reference rectangular planform blade, constant swept blade-tip blade and unconventional aerodynamic shape rotor with CLOR blade-tip. And the rotor sound pressure level, sound pressure time history and sound pressure frequency spectrum for the three rotors under the condition of different rotating speeds and pitch angles on different observing points are measured at outfield. Based upon the experimental results, the comparisons of aeroacoustic characteristics between rotor with CLOR and rotors with rectangular and constant swept bladetip in hover have been made. And some conclusions about the effect mechanism of unconventional aerodynamic shape blade-tip on the rotor aeroacoustic characteristics are obtained combined with the aerodynamic load distributions on the three model blades calculated by CFD method, demonstrating primarily the benefit of rotor with CLOR blade-tip in hover on the aeroacoustic characteristics.