Acoustic Slow-Wave Effect Metamaterial Muffler for Noise Control of HVDC Converter Station

Aiming at the noise control of the HVDC converter station, a one-dimensional two-port metamaterial muffler based on the acoustic slow-wave effect is designed and manufactured. The metamaterial muffler achieves a broadband quasi-perfect absorption of noise from 600 to 900 Hz while ensuring a certain ventilation capacity. In addition, the internal equivalent sound velocity curve and the sound pressure and velocity field of the muffler are used to reveal the mechanism of its broadband quasi-perfect sound absorption. The performance of the muffler was verified by theoretical, numerical, and experimental models. The work in this paper is of guiding significance for solving the noise problem in HVDC converter stations.

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Research of Possibilities of Using the Recycled Materials Based on Rubber and Textiles Combined with Vermiculite Material in the Area of Noise Reduction

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1001.171 ◽

2014 ◽

Vol 1001 ◽

pp. 171-176 ◽

Cited By ~ 4

Author(s):

Pavol Liptai ◽

Marek Moravec ◽

Miroslav Badida

Keyword(s):

Absorption Coefficient ◽

Standing Wave ◽

Sound Pressure Level ◽

Sound Absorption ◽

Sound Pressure ◽

Sound Level ◽

Pressure Level ◽

Sound Absorption Coefficient ◽

Physical Parameters ◽

Materials Research

This paper describes possibilities in the use of recycled rubber granules and textile materials combined with vermiculite panel. The aim of the research is the application of materials that will be absorbing or reflecting sound energy. This objective is based on fundamental physical principles of materials research and acoustics. Method of measurement of sound absorption coefficient is based on the principle of standing wave in the impedance tube. With a sound level meter is measured maximum and minimum sound pressure level of standing wave. From the maximum and minimum sound pressure level of standing wave is calculated sound absorption coefficient αn, which can take values from 0 to 1. Determination of the sound absorption coefficient has been set in 1/3 octave band and in the frequency range from 50 Hz to 2000 Hz. In conclusion are proposed possibilities of application of these materials in terms of their mechanical and physical parameters.

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Sound Absorption for Noise Control and Room-Acoustical Design

Applied Acoustics: Concepts, Absorbers, and Silencers for Acoustical Comfort and Noise Control ◽

10.1007/978-3-642-29367-2_3 ◽

2013 ◽

pp. 15-30

Author(s):

Helmut V. Fuchs

Keyword(s):

Sound Absorption ◽

Noise Control

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Sound absorption of a finite flexible micro-perforated panel absorber back by a rigid air cavity filled with a fibrous porous material

INTER-NOISE and NOISE-CON Congress and Conference Proceedings ◽

10.3397/in-2021-2470 ◽

2021 ◽

Vol 263 (3) ◽

pp. 3625-3632

Author(s):

Ho Yong Kim ◽

Yeon June Kang

Keyword(s):

Energy Dissipation ◽

Porous Material ◽

Fibrous Material ◽

Alternative Energy ◽

Sound Absorption ◽

Sound Pressure ◽

Absorption Coefficients ◽

Air Cavity ◽

Acoustic Cavity ◽

Absorption Performance

Back by a rigid cavity filled with a layer of porous layer, the sound absorption performance of a micro-perforated panel (MPP) can be enhanced in comparison with other resonance based sound absorbers. In this paper, a theoretical model of a finite flexible MPP back by a rigid air cavity filled with a fibrous porous material is developed to predict normal sound absorption coefficients. Displacements of MPP and sound pressure field in fibrous porous material and acoustic cavity are expressed using a series of modal functions, and the sound absorption coefficients of MPP system are obtained. Additionally, comparison of energy dissipation by MPP and fibrous material is performed to identify effects of a fibrous material on the sound absorption of a MPP. As expected, at anti-resonance frequency of an MPP, the fibrous material provide an alternative energy dissipation mechanism.

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