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Open AccessArticle

The Application of a Linear Microphone Array in the Quantitative Evaluation of the Blade Trailing-Edge Noise Reduction

1
School of Power and Energy, Northwestern Polytechnical University, Xi’an 710129, China
2
Key Laboratory of Aerodynamic Noise Control, China Aerodynamics Research and Development Centre, Mianyang 621000, China
*
Author to whom correspondence should be addressed.
Appl. Sci. 2021, 11(2), 572; https://doi.org/10.3390/app11020572
Received: 8 December 2020 / Revised: 4 January 2021 / Accepted: 5 January 2021 / Published: 8 January 2021
(This article belongs to the Special Issue Recent Advances in Flow-Induced Noise)
This paper concerns the application of a linear microphone array in the quantitative evaluation of blade trailing-edge (TE) noise reduction. The noise radiation from the blades with straight and serrated TEs is measured in an indoor open-jet wind tunnel. The array data are processed using the inverse method based on the Clean algorithm based on spatial source coherence (Clean-SC). In order to obtain correct application and achieve the best effect for the microphone array test, the computing software for array data reduction is firstly developed and assessed by Sarradj’s benchmark case. The assessment results show that the present array data processing method has a good accuracy with an error less than 0.5 dB in a wide frequency range. Then, a linear array with 32 microphones is designed to identify the noise source of a NACA65(12)-10 blade. The performance of the Clean-SC algorithm is compared with the Clean algorithm based on point spread functions (Clean-PSF) method for experimentally identifying the noise sources of the blade. The results show that there is about a 2 dB error when using the Clean-PSF algorithm due to the interference of different aerodynamic noise sources. Experimental studies are conducted to study the blade TE noise reduction using serrated TEs. The TE noise for the blade with and without sawtooth configurations is measured with the flow speeds from 20 m/s to 70 m/s, and the corresponding Reynolds numbers based on the chord are from 200,000 to 700,000. Parametric studies of the sawtooth amplitude and wavelength are conducted to understand the noise reduction law. It is observed that the TE noise reduction is sensitive to both the amplitude and wavelength. The flow speed also affects the noise reduction in the serrated TEs. To obtain the best noise suppression effect, the sawtooth configuration should be carefully designed according to the actual working conditions and airflow parameters. View Full-Text
Keywords: broadband noise reduction; trailing edge noise; serrated configuration; microphone array; Clean-SC broadband noise reduction; trailing edge noise; serrated configuration; microphone array; Clean-SC
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MDPI and ACS Style

Chen, W.; Mao, L.; Xiang, K.; Tong, F.; Qiao, W. The Application of a Linear Microphone Array in the Quantitative Evaluation of the Blade Trailing-Edge Noise Reduction. Appl. Sci. 2021, 11, 572. https://doi.org/10.3390/app11020572

AMA Style

Chen W, Mao L, Xiang K, Tong F, Qiao W. The Application of a Linear Microphone Array in the Quantitative Evaluation of the Blade Trailing-Edge Noise Reduction. Applied Sciences. 2021; 11(2):572. https://doi.org/10.3390/app11020572

Chicago/Turabian Style

Chen, Weijie; Mao, Luqin; Xiang, Kangshen; Tong, Fan; Qiao, Weiyang. 2021. "The Application of a Linear Microphone Array in the Quantitative Evaluation of the Blade Trailing-Edge Noise Reduction" Appl. Sci. 11, no. 2: 572. https://doi.org/10.3390/app11020572

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