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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。本文通过对阵列测量的声压信号进行互相关分析,得到管道内顺流和逆流传播的模态声功率结果。安装在风扇实验台进口段的传声器阵列由2排周向间隔180°的轴向阵列组成,每排阵列有14个等间距的传声器。阵列安装在可周向旋转的测量段上,实验中测量段每隔6°旋转一次,共获得840个测点位置的声场信号。结果表明入射波与反射波最大可相差10dB。模态分解结果表明,转静干涉模态是转子通过频率及其谐频处的主导模态。利用不同参考信号计算出的声场结果相同,说明该实验测试方法对参考信号位置没有特殊要求,进一步说明该方法有很好的适用性。
Aeroengine noise reduction research urgently needs a measurement method of wide-band noise in the impeller mechanical pipeline to guide the design of noise reduction. In this paper, the cross-correlation analysis of the sound pressure signals measured by the array is performed to obtain the modal acoustic power results of forward and reverse flow in the pipeline. The microphone array installed at the inlet section of the fan bench consisted of two rows of axial arrays spaced 180 ° apart, each array having 14 equally spaced microphones. The array is mounted on a circumferentially rotatable measuring section. During the experiment, the measuring section rotates once every 6 ° to obtain 840 sound field signals at the measuring point. The result shows that the maximum difference between incident and reflected waves is 10dB. The results of modal decomposition show that the static-interference mode is the dominant mode of the rotor passing frequency and its harmonic frequency. The results of the sound field calculated by using different reference signals are the same, indicating that the experimental test method has no special requirements on the position of the reference signal, further illustrating that the method has good applicability.