航空发动机飞行状态噪声修正方法

Aeroengine Flight Noise Correction Method

中文关键词:  适航  衍生型航空器  飞行状态  噪声修正  航空发动机

英文关键词:airworthiness  derivative aircraft  flight condition  noise correction  aeroengine

中文摘要:

      在适航审定实践中，通过结合基本型航空器飞行噪声数据和衍生型发动机噪声数据，同时从地面噪声向飞行状态噪声 修正，以规避复杂大气条件等因素为试验带来的不确定性，最终评估整机噪声水平。为有效判断衍生型航空器的适航符合性，系 统梳理了导致发动机地面与飞行状态噪声差异的主要影响因素，建立了地面噪声向飞行状态噪声修正的方法。采用声线法消除 大气不均匀性对远场声传播造成的影响，相比将大气视为均匀的传统修正方法提高了准确度。基于国际民航组织推荐方法的框 架编写幅值、指向性变动和声衰减等影响因素相应的计算程序，利用CF34-10A发动机不同工况的地面风扇噪声和喷流噪声数 据，采用该修正方法对不同起飞航迹下的飞越、横侧适航噪声符合性验证测点处的有效感觉噪声级进行了修正计算。结果表明： 所建立的修正方法能够利用发动机地面静态试验噪声评估飞行状态噪声。

英文摘要:

      In airworthiness certification practice, the noise level of the aircraft is evaluated by combining the flight noise data of the baseline aircraft and the noise data of the derivative engine, and correcting the noise from ground noise to flight noise, so as to avoid the uncertainty brought to tests by the complex atmospheric conditions and other factors. In order to effectively assess the airworthiness compli? ance of the derivative aircraft, the main influencing factors leading to the difference between the engine ground and flight noise were systematically identified, and a method of correcting the ground noise to the flight noise was established. The acoustic ray method was adopted to eliminate the influence of atmospheric inhomogeneity on the far-field sound propagation, which improves the accuracy compared with the traditional method treating the atmosphere as homogeneous. Based on the framework of the ICAO recommended method, the corresponding calculation procedures for the influencing factors such as amplitude, directivity change, and sound attenuation were established, and the effective perceived noise levels at the flyover and lateral measurement points for airworthiness noise compliance verification under different takeoff flight trajectories were corrected with the data of ground fan noise and jet noise of the CF34-10A engine under different operating conditions. The results show that the established correction method can utilize the engine ground static test noise to achieve flight noise assessment.