民机机体噪声及其降噪研究

分析了机体噪声源的主要机理及其基本性质。机体噪声由绕起落架装置和高升力系统的流动引起的压强脉动产生。起落架和前缘缝翼产生的基本上是宽频噪声,它们和襟翼的宽频噪声的强度分别随速度的6次方、4.5次方和5次方变化。实际飞行中还应注意存在的"寄生"噪声。此外,较为详尽地讨论了包括QTD II、RAIN、SILENCE(R)和TIMPAN等降噪措施在内的研究项目及其可获得的效果,还讨论了噪声的计算方法,介绍了国外航空界提出的未来民机需降噪的目标,表明民机设计面临降噪的巨大挑战。

Study of airframe noise and its reduction for commercial aircraft

In the present paper the main mechanisms and basic characteristics of the airframe noise are analyzed. The airframe noise is produced by the pressure fluctuation of the flows around the landing gears and high lift systems. Aerodynamic noise from landing gears and leading edge slots are essential broadband noise, their strengths and the strength of broadband noise of flaps are varied with 6th, 4.5th and 5th power of flow velocity respectively. The existence of parasitic noise in flight must be concerned too. The noise reducing projects of QTD Ⅱ, RAIN, SILENCE(R) and TIMPAN are discussed and their results are presented in the paper. The computational methods are briefly introduced. The goals of noise reduction for future commercial aircraft proposed by foreign countries are given, which indicates a huge challenge to the future commercial aircraft design.