【作者】 黄汉超；

【导师】 王华明；

【作者基本信息】 南京航空航天大学 ， 航空宇航科学与技术， 2010， 硕士

【摘要】 随着直升机日益深入研究和广泛应用,直升机噪声的大小已经成为衡量其质量和性能的重要标志之一。尾桨是直升机的主要噪声源之一,研究尾桨噪声特性对控制直升机的噪声水平具有重要意义。本文以直升机尾桨噪声为研究对象,通过对尾桨噪声的机理进行分析,建立了孤立尾桨噪声的计算模型,采用三维非定常面元法计算桨叶表面压力,利用Farassat 1a公式对孤立尾桨的噪声特性进行了数值模拟。构建了一套试验系统,在消声室里进行了孤立尾桨噪声、尾桨与涡干扰噪声的试验研究,测量了不同转速、不同桨叶片数、不同总距角、不同涡干扰角以及不同剪刀角下的尾桨噪声特性。试验结果表明:尾桨叶与涡相互作用时噪声明显增加,而且在尾桨叶与涡正交情况下产生的噪声最大;剪刀式尾桨对尾桨噪声具有调频作用,能够降低尾桨的噪声水平。最后将孤立尾桨噪声的计算结果和试验结果进行了对比分析,验证了计算模型。这些结论为预估直升机的尾桨噪声和指导降低噪声尾桨设计提供了依据。更多还原

【Abstract】 With wide applications of helicopters, helicopter noise level has become one of substantial indexes of helicopter performance and acceptability. Helicopter tail rotor is a major source of the noise; therefore investigation of tail rotor noise characteristics becomes very valuable and important to control the helicopter noise level.This article focuses on researching the helicopter tail rotor noise and analyzing its mechanism to establish the computation model of the isolated tail rotor noise. The three-dimensional unsteady panel method is adopted to calculate the pressure on the surface of the blades and the Farassat la formula is used to simulate the numerical value of the isolated tail rotor noise property. A set of test system has been established, through the experiment of the isolated tail rotor noise, the tail rotor and the vortex interference which are carried out in the anechoic chamber, Test parameters include rotor speed, number of blades, blade pitch angle, vortex interference angle and tail rotor blade azimuth arrangement. The result shows that the noise is markedly increased when the tail blades interacted with the vortex, the noise level under the orthogonal interference is highest.Besides, the scissors-type arrangement of tail rotor can change the noise spectrum and lower the noise level. Last, by contrastive analysis between the results of the isolated tail rotor noise and the experiment, the computation model is being proven. These conclusions can be used to estimate the helicopter tail rotor noise and help to guide tail rotor noise reduction design.更多还原