흡음재 최적 배치를 적용한 흡음형 소음기의 음향성능 연구

강동헌,양해상,성우제 한국음향학회 2024 韓國音響學會誌 Vol.43 No.3

본 논문에서는 흡음형 소음기의 음향성능을 향상시키기 위해 다층 흡음재 배치 순서를 최적화하였다. 소음기의 음향성능은 투과손실로 판단하였으며, 투과손실을 계산하기 위해 유한요소법 기반 수치해석 프로그램을 사용하였다. 흡음재는 흡음형 소음기에서 많이 사용되는 다공탄성 물질인 폴리우레탄을 사용하였으며, 내부에 공기가 흐르는상황을 가정하여 Biot-Allard 모델을 적용하였다. 2 kHz 대역까지 관심주파수 영역을 설정하여 흡음재가 단층으로구성되어 있을 때 음향성능에 영향을 주는 물성치를 확인하였으며, 폴리우레탄 물성치를 바탕으로 단층 및 다층 흡음재를 가진 소음기의 음향성능을 서로 비교하였다. 이후 Nelder-Mead 방법을 적용하여 소음기 내 다층 흡음재의 배치순서를 최적화하였으며, 단층 흡음형 소음기에 비해 평균 투과손실이 증가하는 것을 확인하였다 In this paper, the acoustic performance of an absorptive silencer was enhanced by optimizing an arrangement of multi-layered absorbing materials. The acoustic performance of the silencer was evaluated through transmission loss, and finite element method-based numerical analysis program was employed to calculate the transmission loss. Polyurethane, a porous elastic material frequently used in absorptive silencers, was employed as the absorbing material. The Biot-Allard model was applied, assuming that air is filled inside the polyurethane. By setting the frequency range of interest up to the 2 kHz and the acoustic performance affecting properties of the absorbing materials were investigated when it was composed as a single layer. And the acoustic performance of the silencers with the single and multi-layered absorbing materials was compared with each other based on polyurethane material properties. Subsequently, the arrangement of the absorbing materials was optimized by applying the Nelder-Mead method. The results demonstrated that the average transmission loss improved compared to the single-layered absorptive silencer.

조합형 소음기를 이용한 육상발전용 디젤 엔진의 흡기 소음 제어

송근복(Keun-Bok Song),주원호(Won-Ho Joo),김동해(Dong-Hae Kim) 한국소음진동공학회 2012 한국소음진동공학회 학술대회논문집 Vol.2012 No.4

Turbo-charger noise radiated from air intake part is one of the most important noise sources in diesel power plant. In this paper, intake noise control of the diesel power plant was studied using parallel baffle type silencer and concentric hole-cavity resonator simultaneously. Firstly, acoustical characteristics and attenuation performance for parallel baffle type silencer were investigated through theoretical approach and experimental method. Based on the results, optimal design of the parallel baffle silencer was suggested. Secondly, for reducing the low frequency noise contained in the intake noise, the concentric hole-type resonator was developed and the acoustic performance was verified from the test. By combining two types of silencers, it is expected that the overall insertion loss is about 50 dB. So, the combined silencer is very helpful in reducing the intake noise of diesel power plant.

40 ㎜ 화포의 배플형 소음기에 관한 사격시험 및 전산유체해석 결과비교

김상민(Sang Min Kim),강태엽(Tae Yeob Kang),최시홍(Si Hong Choi),이해석(Hae Suk Lee),김봉수(Bong Soo Kim) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11

This study aims to look into the capability of M&S method such as CFD analysis as a design tool in development of silencer for noise reduction of ordnance. Thus validity of numerical analysis was examined by analyzing differences between measured data of firing test and results of CFD analysis when baffled silencer were applied to 40 ㎜ ordnance . In general, performance of commercial CFD software, ANSYS Fluent V14, was priorly identified whether it can adequately simulate change of flow field caused by firing without silencer and then results of CFD analysis were compared with measured data of firing test as to application of baffled silencer. In conclusion, outcomes of CFD analysis were similar with test and this mean that M&S approach will be able to be used positively in design and development of silencer for large caliber artillery which is planned in a future.

공조소음 저감을 위한 조합소음기 개발

박성종(Seongjong Park),김종도(Jongdo Kim),박용환(Yonghwan Park),김봉재(Bongjae Kim),최호경(Ho Kyung Choi) 대한기계학회 2018 대한기계학회 논문집. Transactions of the KSME. C, 산업기술과 혁신 Vol.6 No.1

공조시스템의 설계에서, 송풍기의 소음을 줄이는 것은 가장 중요한 요소 중 하나이다. 선박용 공조시스템에 널리 사용되는 축류송풍기는 작동성 및 내구성에서 많은 장점을 가지고 있지만, 저주파수대역에 위치한 날개 통과 주파수(BPF) 소음이 문제가 되고 있다. 기존의 소음기는 중중파수 및 고주파수 대역의 소음을 효과적으로 저감하지만, BPF 소음과 같은 저주파수 대역의 소음을 저감하는데 한계가 있다. 본 논문은 BPF 소음을 저감하기 위하여 사이드 브랜치 공명기를 기존 소음기에 적용하는 것을 제안한다. 소음기 내벽 및 공명기의 외벽에 설치된 흡음재와 함께 전체 주파수 대역의 소음을 제어할 수 있다. In the design of HVAC system, reducing the noise from fan is one of the most critical factors. Although axial fan which is widely used in ship HVAC system has many advantages in operability and durability, the low frequency noise called blade passing frequency (BPF) noise has always been an issue. The conventional type of silencer can effectively reduce the noise of mid-high frequency band, but it has limitations on removing noise of low frequency band such as BPF noise. This paper suggests the application of side branch resonators to the conventional silencer to reduce the BPF noise. Along with sound absorbing material installed on silencer inner wall and resonators outer wall, we can control the noise from all frequency bands.

조합형 소음기를 이용한 박용 디젤 엔진 배기 소음 제어

이태경(Lee, Tae-Kyoung),주원호(Joo, Won-Ho),배종국(Bae, Jong-Gug) 한국소음진동공학회 2009 한국소음진동공학회 논문집 Vol.19 No.7

Low frequency exhaust noise of marine diesel engine is one of the most important noise sources in vessels. However, conventional absorptive silencers are ineffective to control exhaust noise because of low absorption in the low frequency range. In the paper, exhaust noise control of marine diesel engine was studied by using the hybrid silencer, which was composed of virtually divided array of concentric hole-cavity resonators and conventional absorptive silencer. A series of tests including field tests were performed to investigate the acoustic performance of the hybrid silencer. Consequently, its high performance of 5${\sim}$10 dB noise reduction in the low frequency range was confirmed and it is expected to be very helpful in reducing the exhaust noise of marine diesel engine.

흡음형과 공명형 덕트 소음기의 소음저감 성능에 관한 실험적 고찰

이영섭(Young-Sup Lee),정광섭(Kwang-Seop Chung),이동훈(Dong-Hoon Lee) 대한설비공학회 2010 설비공학 논문집 Vol.22 No.12

A silencer has been widely used for the purpose of suppressing the noises propagated from duct of air conditioning system. The absorption type silencer is usually applied to reduce the noise with high frequency bandwidth. On the order hand, the resonance type silencer is applied to reduce the noise with low-middle frequency bandwidth. The insertion loss of silencer is measured in the reverberation room. The cut-off frequency of reverberation room is 100 ㎐. The insertion loss of absorption type silencer is more larger than that for resonance type silencer regardless of changing the flow velocity.

방음장치 설계에 따른 유동소음에 대한 실험적 연구

오진우 한국소음진동공학회 2024 한국소음진동공학회 논문집 Vol.34 No.1

현대 사회에서 다양한 설비에 의한 소음으로 인해 소음관련 민원이 지속적으로 발생하고 있으며 점차 증가하고 있는 추세이다. 도심의 개발로 인해 주거지 또는 직장 등 생활공간 주변에서 이러한 소음 발생설비로부터 소음영향을 받는 정도 및 빈도가 증가하고 있고 이에 대한 적극적인 대책이 요구되는 상황에서 소음을 발생하는 사업장 및 공장으로부터의 소음영향성의 감소를 위해 다양한 방음장치가 적용되고 있다. 이 중 소음기와 방음루버는 팬, 공조설비 등 급/배기구를 통해 공기의 순환이 필요한 설비에 적용하는 대표적인 방음장치로 일반적으로 외부 케이싱과 스플리터로 구분할 수 있는데 스플리터는 다양한 길이와 형상으로 설계된다. 결과적으로 유동소음은 소음기와 방음루버의 설계안과 상관없이 시스템 풍량에 비례하여 증가하며 스플리터의 길이보다 형상에 더 큰 영향을 받는 것으로 측정되었다. In modern society, we are exposed to various noise environments. To avoid noise problems, various noise mitigation devices are designed and installed on noise generating facilities. A silencer and an acoustic louver are representative noise mitigation devices for the supply/exhaustion of equipment and the splitter inside the silencer and acoustic louver is designed at various lengths and shapes for the necessary performance. A test is conducted in six steps for various designs of the silencer and acoustic louver. As a result, there is a slight difference in each design but the flow noise is similar at the same step (velocity) as 35dB(A)~73dB(A). This means that the flow-noise is proportional to the system flow velocity. In the case of the acoustic louver, higher flow noise is generated compared to the silencer even if theflow velocity in the duct is low.

고전압 COS 퓨즈용 소음기의 소음저감 및 전류차단 성능에 관한 실험적 연구

이동훈(Lee, Dong-Hoon),송화영(Song, Hwa-Young) 한국소음진동공학회 2008 한국소음진동공학회 논문집 Vol.18 No.7

This experimental study describes the noise reduction and the feasibility of short current of a silencer for a high voltage COS(cut out switch) fuse of a transformer. When a high voltage COS fuse becomes a short circuit by the over current, the strong impulse noise over 150 dB(A) is generated. For the purpose of the reduction of impulse noise, in this study, the diffuser type and the reactive type silencers have been designed and tested, respectively. And also the electrical test on the short current is performed. From the experimental results, the well designed reactive type silencer has been shown to have the noise reduction of about 20 dB(A). It has been found that the feasibility of short current for the COS fuse is closely related to the porosity of the silencer.

모드 매칭법을 이용한 다층 다공성 탄성 흠음재가 채워진 원통형 소음기의 음향투과손실 계산

이종무,양해상,성우제 한국음향학회 2022 韓國音響學會誌 Vol.41 No.4

This paper deals with the process of obtaining sound transmission loss of a cylindrical silencer lined with multi-layered poroelastic sound absorbing materials. The Biot model and the Johnson-Champoux-Allard- Lafarge (JCAL) model were used to deal with waves propagating in multi-layered poroelastic materials. The boundary conditions required for analysis of the silencer were obtained and the numerical process of finding modes was explained. A numerical experiment was conducted on the 2-layered silencer using the modes and the transmission loss converged with the first 12 modes. Finally, the mode matching method proposed in this research was validated by being compared with the results calculated from Finite Element Method (FEM) about different kinds of sound absorbing materials. 본 논문은 다층 다공성 흡음재가 채워진 원통형 소음기의 음향투과손실을 구하는 과정을 다루었다. 다층다공성 흡음재 내부에서 전파되는 파동을 다루기 위해 Biot모델과 Johnson-Champoux-Allard-Lafarge(JCAL) 모델을 이용했다. 소음기 해석에 필요한 경계조건들을 얻었고 그것들을 토대로 수치적으로 모드를 구하는 과정을 설명했다. 얻은 모드들을 이용하여 2층 소음기에 대해 수치적인 실험을 진행했으며 처음 12개의 모드만으로도 음향투과손실이 수렴함을 보였다. 마지막으로 흡음재의 종류를 바꿔가면서 음향투과손실을 계산했고 이를 유한요소법을 이용한결과와 비교함으로써 본 연구에서 제시한 모드 매칭법의 유효성을 검증했다.

공기 유동소음 저감을 위한 소음기 개발

최두석(Doo-Seuk Choi),김영춘(Young-Chun Kim),박성영(Sung-Young Park) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5

Vortex tube is the device that can separate small particles from the compressed gas, as well as compressed gas into hot and cold flow. Because a vortex tube uses strong swirl velocity, it generates a high pitch noise. In this study 4 different silencers are tested to reduce vortex tube flow noise. Three are commercial silencer applied in pneumatic system, and the other is perforated silencer. As a result, 1/4 inch silencer shows the best sound absorption characteristics for all inlet air pressure range. 1/2 inch and 3/8 inch silencer show very similar sound absorption characteristics. However, perforated silencer shows sound absorption characteristics similar to 1/2 inch silencer at low inlet pressure, but shows the worst characteristics at high inlet pressure.