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.
XU Kunbo
,
QIAO Weiyang
,
CHANG Xinyue
,
YIN Tao
,
HUO Shiyu
. Fan broadband noise based on combined sensor array method[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2017
, 38(12)
: 121324
-121324
.
DOI: 10.7527/S1000-6893.2017.121324
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