摘要
针对叶轮机械管道内宽频噪声模态分解以及声功率测量,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。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,该方法可以准确地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得很好,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。
This paper uses a combined sensor array method to decompose ducted broadband noise into mode terms and to measure sound power within turbomachinery.The novelty of this method is that the number of required sensors is drastically reduced in comparison with current standard techniques,and only an axial line of microphones and one circular sensor ring are required.This superiority is more obvious in measurement of ducted broadband noise at medium and high frequencies.A numerical investigation on the accuracy and validity of this method is presented,including validating the accuracy experimentally for the first time.The synthetic sound fields in the numerical study are generated by several rings of uncorrelated monopole sources.Numerical results show that the characteristics of mode coherence coefficients are strongly dependent on the number of monopole sources and also the compactness of source distribution.The method is shown to be able to predict the incident broadband sound power with deviation less than 3 dB when mode waves are almost mutually uncorrelated.The fan ducted sound power calculated by this method is excellently consistent with that of current standard techniques.The deviation is less than 1 dB in the determination of incident sound waves,and increases to 3 dB in the reflected direction.
出处
《航空学报》
EI
CAS
CSCD
北大核心
2017年第12期24-38,共15页
Acta Aeronautica et Astronautica Sinica
基金
国家自然科学基金(51476134)
中国-欧盟航空科技国际合作项目(688971)~~
