轴流风扇宽频噪声声功率实验研究

Experimental research of broadband sound power determination in axial fan

航空发动机降噪研究迫切需要一种叶轮机械管道内宽频噪声测量方法来指导降噪设计。为了研究管道内宽频噪声,利用沿管道内壁面布置的环形麦克风阵列对单级轴流风扇进行了噪声测量,通过测量信号与参考信号互相关以及奇异值分解(SVD)方法成功地得到管道内宽频噪声结果。结果表明:该方法不仅可以计算出管道内主要单音,而且可以计算宽广频率范围内的宽频噪声;并能有效分辨出管道内向前和向后传播的声功率。宽频噪声结果证实该方法可以应用到高背景噪声和硬壁反射下的管道内声场研究。

it is in urgent need for aircraft engine noise reduction research to find a kind of measurement technique for broad-band noise determination in turbomachinery duct to guide the noise reduction design. In this paper, we use wall-flush annular- ly installed microphone array to measure the noise of axial fan and finally obtain the broadband sound power in duct by means of cross-spectra between measurement signals and reference signal and the application of singular value decomposition （SVD） method. The results show that this experimental technique enables the calculation of not only in-duct transmitted sound power for dominant tones, but also broadband noise over a wide frequency range; this method also helps to distin-guishe between sound power transmitted in and against the direction of flow. Broadband noise results confirm that this meth- od behaves fairly robust in loud background noise and hard wall reflection condition.