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Experimental Investigation on Influence Factors of Active Noise Attenuation of Sound-insulation Ventilation Window

YU Hao-xin;CHEN Ke-an;HU Han;MA Xi-yue

2012, 32 (3): 191-197. DOI: 10.3969/j.issn.1006-1355.2012.03.044

Abstract （1759）

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The factors influencing the active noise attenuation of a sound-insulation ventilation window were investigated experimentally. The window system was constructed by staggering the opening sashes of a spaced double glazing window to allow ventilation. Transparent microperforated absorbers (MPA) and sound-absorbing material were used along the ventilation path to attenuate external noise. The performances of the four-input and four-output active control system for the window with different secondary source locations and secondary-path modeling length were compared mutually. It is found that to achieve the considerable attenuation effect in the surface of the window, locations of the secondary sources should be so arranged that the effective scope of the secondary sound field can cover the inner space of the window and the noise energy can be reduced, or the sound field is directed to the internal window glass to directly control the radiation noise. If the optimal length of the secondary-path modeling cannot be achieved in actual application, a longer modeling length should be chosen appropriately to avoid degenerating the noise attenuation or leading the system instability.

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Physical Mechanisms of Active Acoustical Control for Double-panel Structure

ZHANG Xian-ying;CHEN Ke-an;HU Han;MA Xi-yue

2012, 32 (2): 102-107. DOI: 103969/j.issn.1006-1355-2012.02.025

Abstract （1155）

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The theoretical model of a double-layer panel for active control of sound radiation was established based on the vibro-acoustic coupling equations. Then, the optimal secondary control force was obtained by minimizing the sound power of the panel. Next, the sound intensity distribution on the observed surface was calculated. Finally, the simulation results were analyzed in terms of the sound intensity in the near-field, and a preliminary conclusion for the mechanism of active control of this structure were obtained.

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Layout Optimizingation of Electro-acoustic Devices of Active Noise Control System for 110 kV Transformer

MA Xi-yue;CHEN Ke-an;HU Han

2011, 31 (6): 109-115. DOI: 10.3969/j.issn.1006-1355-2011.06.024

Abstract （1759）

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The principle of active noise control using multiple secondary sources and error sensors in free special acoustic field is introduced. According to the measured sound pressure of 110kV transformer’s noise, a low-frequency noise-control strategy is proposed for the transformer with the use of multi-source arrays. The influence of different numbers of secondary sources and error sensors and their special layout on the control effect is analyzed through numerical simulation. Theoretically, the more the secondary sources and error sensors are, the better the control effect is. But excessive secondary sources and error sensors will lead to increasing of channels of the control system, so that the control system is unlikely to be implemented. Finally, considering the feasibility of the control system in physical point of view, an optimal control system which can yield good control effect with relatively less secondary sources and error sensors is made.