飞机机体表面声压及舱内降噪优化设计

本文以某型客机为研究对象，从飞行试验数据分析和声学建模两方面研究机体表面声压分布及其对舱内壁板近场辐射声压的影响。首先根据试飞数据分析了机体表面声压分布，然后利用统计能量法建立飞机客舱中后段的声学模型，以试飞数据作为声源输入，研究机体表面声压分布对客舱内部壁板附近声压分布的影响，并在此基础上提出优化设计方案，通过模型验证优化方案的有效性。试飞数据表明：机体表面声压在后应急门前方、靠近地板处最大；巡航速度升高，声压级较大区域的面积随之增加；巡航高度和发动机N1N2频率变化对机体表面声压级分布无明显影响。仿真数据表明：仅蒙皮结构无法有效降低客舱噪声；对声学降噪包进行优化能增加壁板隔声量，降低舱内声压。

Sound pressure distribution on the external surface of an aircraft and the optimization of the cabin acoustic design

This paper presents the analysis of the external sound pressure distribution on the external surface of a commercial aircraft based on a flight test data. This data was consequently used in a Statistic Energy Analysis (SEA) model as the external noise sources to predict the sound pressure distribution inside the cabin along the longitudinal direction. Based on the flight test data and the predicted results, two designs for the sound package optimization were proposed and validated by the SEA model. The flight test data illustrates that the external sound pressure peaks around the floor area near the emergence door. The increase of the cruising speed results in the increase of the area with high sound pressure on the external surface of the aircraft. The cruising height and the variation of the N1 and N2 frequencies of the engine are of minor importance on the external sound pressure distribution. The predicted result indicates that without the sound package and the trim panels the fuselage structure itself is unable to insulate the external sound energy. The proposed designs are able to reduce the cabin noise and improve the sound insulation of the aircraft.