• Title/Summary/Keyword: Absorptive Duct Silencer

Search Result 7, Processing Time 0.02 seconds

A Study on Sound Attenuation by Structure Improvement of Silencer for Exhaust Fan (배기소음기의 구조개선에 의한 소음감쇠 효과에 관한 연구)

  • 윤세철;이해경
    • Journal of the Korean Society of Safety
    • /
    • v.10 no.2
    • /
    • pp.32-38
    • /
    • 1995
  • The silencers are used to attenuate noise generated by the exhaust fan for industrial processes. The types of silencers applied in this study are absorptive duct silencer, expansion chamber, absorptive chamber and resonator. This study was carried out to verify the attenuation by the various silencers and elements. As a result, the difference of attenuation between the calculation and the measurement was about 1-7㏈. The attenuation by absorptive duct silencer and absorptive chamber was negligible at frequencies below 250Hz. The expansion chamber should be used for low frequency applications where the absorptive duct silencer was Ineffective. The attenuation by resonator may be realised when the ratio of frequency to resonant frequency approaches 1.

  • PDF

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
    • /
    • 2006.05a
    • /
    • pp.1209-1211
    • /
    • 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.

  • PDF

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
    • /
    • 2005.11a
    • /
    • pp.500-505
    • /
    • 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.

  • PDF

A Study on the Performance Improvement of Medium Speed Diesel Engine Exhaust Silencer in the Low-frequency Range Using Array Resonators (공명기 배열을 이용한 중속 디젤엔진 배기 소음기의 저주파수 대역 성능 개선 연구)

  • Kim, Young-Hyun;Joo, Won-Ho;Bae, Jong-Gug
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.19 no.7
    • /
    • pp.693-698
    • /
    • 2009
  • Various acoustic tests were carried out to investigate the acoustic performance of diesel engine exhaust silencers. In order to consider flow effects, the test facility was set up composed of fan, duct and silencer. Using the test facility, insertion loss tests were carried out to improve the acoustic performance in the low-frequency ranges. Through a series of tests, it was found out that the array resonators having multi-perforated holes inside the exhaust silencer, might be very effective in the low frequency range. Consequently, the hybrid-type silencer which is the combination of reflective silencer with array resonators and conventional absorptive silencer, was proposed and its high performance in the low-frequency range was also verified.

A Study on the Improvement of Acoustic Performance of Diesel Engine Exhaust Silencer in the Low-Frequency Range using Array Resonators (공명기 배열을 이용한 디젤엔진 소음기의 저주파수 대역 성능 개선 연구)

  • Lee, Tae-Kyung;Kim, Young-Hyun;Joo, Won-Ho;Bae, Jong-Gug
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2007.05a
    • /
    • pp.30-35
    • /
    • 2007
  • Various acoustic tests were carried out to investigate the acoustic performance of diesel engine exhaust silencers. In order to consider flow effects, test equipment composed of fan, duct and silencer was set up. Using the test equipment, insertion loss tests were carried out to improve the performance in the low-frequency ranges. Through a series of tests, the fact that array resonators may be effective in the low-frequency noise has been verified. Consequently, the hybrid-type silencer which is the combination of reflective silencer with array resonators and conventional absorptive silencer were proposed and its high acoustic performance in the low-frequency range has also been verified.

  • PDF

The Estimation of Sound Attenuation Caused by Duct Silencer Using Sound Intensity Method (음향인텐시티법을 이용한 공조 덕트소음기의 감음성능평가방법에 관한 연구)

  • Kim, Seok-Hong;Son, Jang-Yeol;O, Jae-Eung;Kim, Yeo-Sik
    • The Journal of the Acoustical Society of Korea
    • /
    • v.6 no.2
    • /
    • pp.54-61
    • /
    • 1987
  • This paper is to suggest the test method of sound attenuation caused by absorptive duct silencer using sound intensity method in field. In order to estimate sound attenuation, sound power being radiated from sound power source and duct exhaust terminal was measured by the sound pressure method and sound intensity method in semianechoic and common room. The results of the measured sound attenuation values by sound intensity method are more similar to those of theoretical calculation than those by the sound pressure method. In addition, sound intensity method is much less influenced by sound field condition or continuous background noise than the sound pressure method.

  • PDF

An Experimental Study on Acoustic Performance of Splitter Silencers in Large Maritime Gas Turbine Engines (해상용 가스터빈의 스플리터 소음기 성능에 대한 실험적 연구)

  • Baek, Seonghyeon;Lee, Kanghee;Kang, Kyungsik;Lee, Iljae
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.25 no.7
    • /
    • pp.503-509
    • /
    • 2015
  • Based on ISO 7235, an experimental setup to measure the acoustic performance of splitter type dissipative silencers was fabricated. The length of each duct, sound source, microphone locations, modal filter, and anechoic termination were considered in the design of this setup. The modal filter is a particularly important factor because it affects the limit of measurement. The effects of number of splitters, absorptive material density, perforate plate, and media on the noise reduction of the sample silencers were experimentally investigated. The experimental results show that the insertion loss of a silencer with media, high perforate opening, and higher number of splitters increases especially at higher frequencies.