• Title, Summary, Keyword: Perforated Panel System

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A Study on the Absorption Performance of a Perforated Panel type of Resonator (다공패널형 공명기의 흡음성능에 관한 연구)

  • Song, Hwayoung;Yang, Yoonsang;Lee, Donghoon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.28 no.6
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    • pp.224-231
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    • 2016
  • When aiming to reduce the low frequency noise of a subway guest room through sound absorbing treatment methods inside the wall of a tunnel the resonator is often more effective than a porous sound absorbing material. Therefore, the perforated panel type resonator embedded with a perforated panel is proposed. The perforated panel is installed in the neck, which is then extended into the resonator cavity so that it can ensure useful volume. The absorption performance of the perforated panel type of resonator is obtained by acoustic analysis and experiment. The analytical results are in good agreement with the experimental results. In the case of multiple perforated panel type resonators, as the number of perforated panels increase, the 1st resonance frequency is moved to a low frequency band and sound absorption bandwidth is extended on the whole. In order to obtain excellent absorption performance, the impedance matching between multi-panels should be considered. When the perforated panel in the resonator is combined with a porous material, the absorption performance is highly enhanced in the anti-resonance and high frequency range. In case of the resonator inserted with perforated panels of 2, the 2nd resonance frequency is shifted to a low frequency band in proportion to the distance between perforated panels.

Noise Reduction of a Ventilating Fan System using Micro-Perforated Panel (미세 다공판을 이용한 환기팬 시스템의 소음저감)

  • Lee, Jong-Seuk;Song, Hwa-Young;Lee, Dong-Hoon;Kwon, Hyuk-Jung;Kim, Dong-Yun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1209-1211
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    • 2006
  • This paper introduces an experimental study for the noise reduction of a ventilating fan system. For the purpose of noise reduction, conventionally an absorptive duct silencer filled with a glass fiber has been utilized. However, a glass fiber has some disadvantages like hygiene and secondary pollution problems. In order to overcome these problems, in this paper, a perforated duct silencer has been applied to the ventilating fan system. For the designing of a perforated duct silencer, the transmission losses for various perforated panel systems are measured and compared with its noise reduction performance.

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A Study on the Improvement of Acoustic Absorption of Multiple Layer Perforated Panel Systems (다중 다공판 시스템의 흡음성능 향상에 관한 연구)

  • Lee, Dong-Hoon;Seo, Seong-Won;Hong, Byung-Kuk;Song, Hwa-Young
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.5
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    • pp.571-577
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    • 2005
  • The acoustic absorption of multiple layer perforated panel systems is largely reduced at the anti-resonance frequency. In order to improve the acoustic absorption at the anti-resonance frequency, the sound absorbing materials are inserted between perforated panels. By the insertion of absorbing materials, it is found that the multiple layer perforated panel system has better acoustic absorption at the anti-resonance frequency and more broadband frequency. Besides, it is shown that the absorption coefficients from the transfer matrix method agree well with the values measured by the two-microphone impedance tube method for various combinations of perforated panels, airspaces or sound absorbing materials.

Noise Reduction of a Range Hood using Micro-Perforated Panel (미세 다공판을 이용한 레인지 후드의 소음저감)

  • Kim, Deok-Han;Song, Hwa-Young;Lee, Dong-Hoon;Lee, Chang-Kun;Kim, Dong-Yun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1205-1208
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    • 2006
  • This paper introduces a study for the noise reduction of a range hood for household. Generally, range hoods have a built-in sirocco fan from which rumbling noise is generated. Though the rumbling noise has low noise level. this noise makes most of the users nervous due to the its low frequency characteristics. For the purpose of noise reduction, in this study, a micro-perforated panel system is installed in the fan housing of range hood. From the experimental results, it is confirmed that the noise level emitted from the range hood is decreased over 2dB(A) in all frequency regions due to the effect of noise reduction by micro-perforated panel system.

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An Experimental Study on the Noise Characteristics and Reduction of a Ventilating Fan System (환기팬 시스템의 소음특성과 저감에 관한 실험적 연구)

  • Kim, Deok-Han;Lee, Dong-Hoon;Kwon, Hyuk-Jung;Kim, Dong-Yun;Lee, Jong-Seok
    • Proceedings of the SAREK Conference
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    • pp.500-505
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    • 2005
  • This paper introduces an experimental study for the noise characteristics and reduction of a ventilating fan system. For the purpose of noise reduction of it, an absorptive duct silencer filled with a glass fiber has been conventionally utilized. However, a glass fiber has some disadvantages like hygiene and secondary pollution problems. In order to overcome these problems, in this paper, a perforated duct silencer has been applied to the ventilating fan system. For the designing of a perforated duct silencer, the transmission losses for various perforated panel systems are measured and compared with their sound absorption performances.

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A Study of Sound Absorbing Characteristics of the Railway Noise Barrier with Respect to Front Perforated Panel and Absorbing Material (철도 방음벽의 전면 타공과 흡음재 변화에 의한 흡음성능 고찰)

  • Kim, Kwanju;Lee, Junheon;Kim, Sanghun;Park, Jinkyu
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.4
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    • pp.275-281
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    • 2014
  • This study has been analyzed the sound performance of the noise barriers with respect to the configuration of the front perforated panel geometries and the filled absorption materials. Noise barriers' acoustic performance should be required to meet 0.7 of NRC value at least. The global absorbing performance of the barriers have been investigated by changing the opening ratio of the front perforated panel and the absorbing characteristics of the absorbing material using two microphone method. Therefore, It it possible to obtain to increase acoustic performance of the specific frequency ranges by designing the perforate rates of the front panel and absorbing characteristics of the absorbing materials inside, as well. This study try to find out the possibilities of applying the absorbing noise barrier to railway usage.

A study on the Room Acoustic Renovation of Music Room at Daihyun Elementary School in Yongin (초등학교 음악실의 실내음향 개선에 대한 연구 - 대현초등학교 사례를 중심으로 -)

  • Choi, Won-Gab;Shin, Jic-Soo
    • Journal of the Korean Institute of Educational Facilities
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    • v.13 no.1
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    • pp.17-25
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    • 2006
  • Elementary school classroom designs have been developed toward open education system to provide students diverse and improved educational environments since the early of 1990 in Korea. Unfortunately, the quality of music room has not still shown dramatic improvements due to the lack of the acoustical knowledges of architects. This report aims to investigate typical acoustic quality of previous or current music room of elementary schools and show new acoustic treatment technologies to improve the room acoustic of music room by adapting composite perforated panel system and diffusion technology. The music room at Daihyun Elementary school in Yongin was chosen as a case study of this report. The music room was measured to be analyzed using field measurements and the acoustical specifications of composite perforated panel systems and kinds of diffusors were set. Acoustic measurements were performed after the renovation to show the differences between previous room acoustic and after the acoustic renovations. As the result, the case study has shown that the new composite perforated panel systems and diffusion surfaces lowered reverberation time at proper level along with improving the clarity of music, RASTI, and spatial impressions. Also, acoustic interferences such as comb filtering and flutter echoes have been controlled dramatically by diffusive surfaces. The study shows music rooms in elementary schools, middle and high schools can be improved by adapting composite perforated panel systems and diffusors.

An Experimental Study on the Grazing Incidence Sound Absorption of a Perforated Panel System (다공판 시스템의 접선입사 흡음성능에 관한 실험적 연구)

  • Je, Hyun-Su;Yang, Soo-Young;Hong, Byung-Kuk;Song, Hwa-Young;Lee, Dong-Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1052-1055
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    • 2004
  • This paper introduces an experimental study on the grazing incidence sound absorptions for duct silencers filed with a glass wool and consisted of a perforated panel. The experimental results are discussed in comparison with the normal incidence sound absorption. And also the transmission loss for duct silencers are measured and compared with the sound absorption performances. From the experimental results, it is shown that the resonance frequency bandwidth on the transmission loss and sound absorption coefficient for duct silencers has a good agreement.

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Absorption Characteristics of Micro-perforated Panel Absorber According to Incident Pressure Magnitude and Its Geometric Parameters (가진 음압 및 설계 인자에 따른 미세 천공판 흡음 기구의 흡음 특성)

  • Park, Soon-Hong;Seo, Sang-Hyun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.178-185
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    • 2011
  • The micro-perforated panel absorber (MPPA) is one of promising noise control elements because of its applicability to extreme environments where general porous materials cannot be used. Since the MPPA is inherently non-porous sound absorber, it can be a good candidate of acoustic protection system of a space launcher. The overall sound pressure level inside payload fairings of commercial launch vehicles is so high (around 140 dB OASPL) that the conventional linear impedance model cannot be directly applied to the design of the acoustic protection systems. In this paper an acoustic impedance models of a micro-perforated panel absorber at high sound pressure environment were reviewed and the use of the impedance on the practical design of MPPAs was addressed. The variation of absorption characteristics of MPPA was discussed according to the design parameters, e.g., perforation ratio, the minute hole diameter, the thickness of MPP and the incident sound pressure level.

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Absorption Characteristics of Micro-perforated Panel Absorber According to High Incident Pressure Magnitude and Variation of Geometric Parameters (높은 입사 음압 및 설계 인자의 변화에 따른 미세 천공판 흡음 기구의 흡음 특성)

  • Park, Soon-Hong;Seo, Sang-Hyun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.11
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    • pp.1059-1066
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    • 2011
  • The micro-perforated panel absorber(MPPA) is one of promising noise control elements because of its applicability to extreme environments where general porous materials cannot be used. Since the MPPA is inherently non-porous sound absorber, it can be a good candidate of acoustic protection system of a space launcher. The overall sound pressure level inside payload fairings of commercial launch vehicles is so high(around 140 dB OASPL) that the conventional linear impedance model cannot be directly applied to the design of the acoustic protection systems. In this paper an acoustic impedance models of a micro-perforated panel absorber at high sound pressure environment were reviewed and the use of the impedance on the practical design of MPPAs was addressed. The variation of absorption characteristics of MPPA was discussed according to the design parameters, e.g., perforation ratio, the minute hole diameter, the thickness of MPP and the incident sound pressure level.