大型客机机体噪声机理及控制技术

Mechanism and control of airframe noise of large passenger aircraft

  • 摘要: 气动噪声问题不仅是大型客机适航取证的关键技术难题,更是关系到乘客舒适度的重要技术指标。增升装置噪声和起落架噪声是大型客机机体噪声的主要来源。本文针对我国大型客机研制中增升装置噪声和起落架噪声的产生机理及控制关键科学问题,开展噪声源、远场声辐射精细化数值模拟。针对噪声产生机理,发展了近壁面边界涡量流、拟涡能流等涡动力学过程与涡声理论相结合的噪声源分析方法;针对机体噪声控制难题,提出了缝翼凹腔小尺度波纹噪声控制方法和起落架支杆大尺度波纹噪声控制方法。数值模拟结果表明:缝翼凹腔是增升装置的重要噪声源之一;中低频噪声和纯音峰值主要来自缝翼凹腔和主翼前缘,后缘襟翼对噪声的贡献相对较小;起落架尾迹区域和轮胎空腔区域存在大量、复杂的大尺度湍流涡结构,是起落架的主要噪声源,起落架各部件噪声特性基本呈现宽频特性,支柱部件辐射噪声最大,轮胎次之,中间的连轴部件和扭杆部件辐射噪声相对较小;缝翼凹腔波纹噪声控制方法兼具减阻和降噪功效;起落架大尺度波纹噪声控制方法能有效降低远场辐射噪声。本文研究内容可为增升装置气动与噪声一体化设计、起落架降噪设计等提供技术支撑。

     

    Abstract: The aerodynamic noise is not only the key problem of airworthiness forensics of large airliners, but also an important index related to passenger comfort. High lift device noise and landing gear noise are the main sources of airframe noise. In this paper, the key problems of the noise mechanism and control of the noise high lift device and landing gear in the development of large passenger aircraft are studied. In view of the noise generation mechanism, a novel noise source analysis method is proposed for vortex dynamics processes such as vorticity near wall boundary and boundary vorticity flux. Aiming at the noise control of the airframe, the small-scale wavy control method of the slat wing cove and large-scale wavy control method of landing gear support strut are proposed. The numerical results show that the slat cove is the main noise source of the high lift devices. The noise and pure tone peaks of the low and middle frequencies are mainly from the slat cove and the leading edge of the main wing, and the trailing edge flap makes a relatively small contribution to the noise. A large number of complex large-scale turbulent vortex structures exist in the wake region of the landing gear and the cove region of wheels, which are the main noise source of the landing gear. The noise characteristics of each landing gear component basically exhibit broadband characteristics. The strut component has the largest radiation noise, and the axle and torque link components have relatively small radiation noise. The slat cove wavy noise control method has both drag reduction and noise reduction effects. The large-scale wavy noise control method of the landing gear can reduce the far-field radiation noise effectively. The research content of this paper provides technical support for the integrated pneumatic and noise design of high lift device and noise reduction design of the landing gear.

     

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