新舟60飞机APU排气噪声测量和分析

The Measurement and Analysis of Exhaust Noise of APU on MA 60 Aircraft

由于新舟60飞机APU排气噪声辐射较严重,为了确定一种最佳的降噪方案,必须对新舟60飞机APU排气噪声的频谱特性和指向性进行测量并分析。从测量结果可以看出,无论APU工作在哪种工作状态,排气噪声均属于宽频噪声,主要是1000Hz以上的高频噪声,而满负载状态下的排气噪声除了高频含量之外,在400～1000HZ范围内也有较强的噪声。另外还发现,排气噪声有非常强的方向性。

The exhaust noise radiation of A PU(Auxiliary power units)on MA60 aircraft is serious.Effective sound treatment t echnology should be adopted for controlling exhaust noise.For finding best metho d for reduction of APU exhaust noise,the noise spectrum and directivity should b e measured.The measured spectrum of APU exhaust noise show that typeical exhaust noise spectrum is very broad.Two general regions can be distinguished.A broad h ump of low frequency random noise centering in the 4001000Hz region normally i s present,which often is substantially stronger with load.A second broad hump of high frequency random noise centers in speech interference region 10005000Hz, which is the frequency range of the ear's greatest acuity.