基于参考信号方法的叶轮机械宽频噪声试验研究

An Experimental Investigation on Turbomachinery Broadband Noise Based on Reference Signal Method

航空发动机降噪研究迫切需要1种叶轮机械宽频噪声测量方法。通过在单级轴流风扇进口段布置的4圈环形麦克风阵列对管道内宽频噪声进行了测量,每圈阵列由8个环壁面布置的传声器组成。在40%~100%设计转速下,利用互相关方法对管道内宽频噪声进行了试验研究。结果表明:在相同转速不同工况下的噪声结果差别很小。该方法能准确地对管道内模态波进行分解,并分辨出顺流和逆流传播的模态波,进一步证实了互相关方法在管道宽频噪声测量方面有很好的鲁棒性。

Noise reduction research in aeroengine urgently needs an experimental method to measure turbomachinery broadband noise. Four rings of microphones installed upstream of an axial fan were used to measure the broadband ducted noise, each ring was composed of 8 wall-flush mounted microphones. Experiments were conducted at different conditions from 40% to 100% design speed, and broadband noise results were analyzed by correlation method. Results show that there is little difference in the decomposed broadband sound fields when different conditions are operating at the same rotating speed. The method can accurately decompose the sound fields into modal terms and distinguish the mode waves both along and against flow directions. Cross-correlation method is furtherly proved to be robust in broadband noise determination.