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针对叶轮机械管道内宽频噪声模态分解以及声功率测量,本文基于组合传声器阵列方法对风扇管道宽频噪声进行了研究。与当前的成熟测量方法相比,该方法最大的优势是所需声压测点的个数大大减少,仅需要安装由单独一圈传声器和一排轴向传声器组成的麦克风阵列,这种优势在中高频管道宽频噪声测量上尤为突出。本文针对该方法的有效性和准确性进行了数值研究,并首次试验验证了该方法的精确性。在数值模拟中,人工模拟的声场是由几圈不相干的单极子声源激发产生的,模拟结果表明宽频噪声模态相干特性严重依赖于单极子声源的个数以及其紧凑性。当频率段内的管道模态近似完全不相干时,该方法可以准确的计算出入射声波的宽频噪声声功率,最大误差小于3dB。在风扇管道宽频噪声声功率计算方面,该方法与现有的成熟方法符合的很好,在入射声波的估计上,最大误差小于1dB,而在反射声波的测量上最大误差小于3dB。
Aimed at the wide-band noise modal decomposition and the acoustic power measurement in the impeller mechanical pipeline, this paper studied the broadband noise of the fan pipeline based on the combined microphone array method. Compared with the current mature measurement methods, the biggest advantage of this method is that the required number of sound pressure measurement points is greatly reduced, only need to install a microphone array consisting of a single ring microphone and a row of axial microphones, this advantage in High frequency broadband noise measurement is particularly prominent. In this paper, we study the validity and accuracy of this method numerically and verify the accuracy of this method for the first time. In the numerical simulation, the artificial simulated sound field is excited by a few laps of uncoherent unipolar sound source. The simulation results show that the wide-band noise modal coherence properties depend heavily on the number of monopole sources and their compactness. When the duct modes in frequency band are completely irrelevant, the method can accurately calculate the broadband noise acoustic power of incident sound waves with the maximum error less than 3 dB. The method is in good agreement with the existing mature methods in the calculation of the broadband noise power of fan duct. The maximum error of incident sound wave is less than 1 dB while the maximum error of reflected sound wave is less than 3 dB.