战斗机座舱内气动噪声分析

目的降低座舱气动噪声提供分析方法及数据。方法以某型机的座舱为研究对象,利用CFD流场分析方法对某型机的座舱外表面瞬态压力场进行分析和提取,作为舱内声场分析的外部激励,利用声学边界元方法计算得到座舱内部声场分布和声压大小,以及结构参数与舱内噪声的关系。结果某型机舱内声场的声压在500 Hz以下的低频段最大,且声压随频率的增加而降低,在2500 Hz以后趋于平缓,座舱内飞行员头部位置最大声压112 d B。后舱飞行员右耳位置声压,多数情况下大于前舱飞行员头部声压。结论分析结果表明,某型机后舱透明件的外表面受固定的空中受油管导致的湍流和进气道内的脉动压力,是座舱内噪声的主要来源。要降低舱内噪声,除了优化外形设计外,通过声传递向量分析,有目的地对结构参数进行调整,是一个较好的解决方案。

Aero-acoustic Analysis on Fighter Cockpit

Objective To provide approach and data to reduce the aero-acoustic noise in cockpit. Methods The cockpit of a certain aircraft was taken as the object of study. Firstly, based on the CFD method, the fore-body surface transient pressure field was obtained and dealt as the aero-acoustic external excitation. Then, the cockpit interior sound field, sound pressure, and the relationship between structure parameters and noise in cockpit were obtained with the approach of acoustic boundary element. Results The sound field of fighter cockpit cabin showed that the largest acoustic pressure appeared in frequency range lower than 500 Hz, and the acoustic pressure decreased with the increase of frequency. Change of acoustic pressure trended to flat when the frequency was higher than 2500 Hz. The maximum acoustic pressure at the head of pilot in the cockpit was 112 dB. In majority cases, the acoustic pressure at the right ear of pilot in the back cockpit was larger than that at the head of pilot in the front cockpit. Conclusion The results show that, the turbulence caused by refueling pipe fixed on forebody and the fluctuating pressure from inlet are the main noise sources in the cockpit. To reduce the noise in cockpit, apart from optimizing the shape design, adjusting the structural parameters based on analysis of acoustic transfer vector is also an effective choice.