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해상용 대형 가스터빈의 소음 저감을 위한 흡음형 소음기의 설계 및 성능 측정
백성현(Seonghyeon Baek),이강희(Kanghee Lee),권대훈(Daehun Gwon),이일재(Iljae Lee) 한국소음진동공학회 2014 한국소음진동공학회 학술대회논문집 Vol.2014 No.10
Based on ISO 7235, an experimental setup to measure the acoustic performance of splitter type dissipative silencers are fabricated. The length of each duct, sound source, microphone locations, modal filter, and anechoic termination are considered in the design of this setup. The modal filter is a particularly important factor because it affects the limit of measurement, which is also determined by the amount of flanking transmission of sound generated by the sound source to microphones. The effects of absorptive materials, media which covers the materials, and the number of splitters on the noise reduction of the sample silencers are experimentally investigated. The insertions loss of silencers with media and higher number of splitters increases, especially at higher frequencies.
해상용 가스터빈의 흡음형 소음기 성능에 대한 3차원 해석적 연구
이창헌(Changheon Lee),백성현(Seonghyeon Baek),권대훈(Baek, Daehun Gwon),이일재(Iljae Lee) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.10
Acoustic behavior of dissipative silencers with splitters was analyzed by using 3-dimensional commercial software. An impedance tube setup was used to obtain the flow resistivity of mineral wool. The resistivity is used as an input parameter for the calculation of insertion loss of silencers. The comparison of insertion loss predictions with the experimental results shows reasonable agreements. For large silencers, it needs a large number of elements especially at high frequencies and thus long computation time. To reduce computation time without sacrifice of accuracy, predictions for various partial models were presented. Partial model can be used as a representation of the full model with relatively short computation time. It can be concluded from more predictions with different flow resistivity that lower flow resistivity may decrease the insertion loss, but higher resistivity slightly improves it.
대형 스플리터 소음기 성능에 대한 3차원 수치해석적 연구
백성현(Seonghyeon Baek),이창헌(Changheon Lee),권대훈(Daehun Gwon),이일재(Iljae Lee) 한국소음진동공학회 2017 한국소음진동공학회 논문집 Vol.27 No.2
Acoustic performance of splitter silencers was investigated by using 3-dimensional commercial software and experiments. Flow resistivity of sound absorbing material was indirectly estimated by using an impedance tube setup and a curve fitting method. In addition the acoustic impedance of perforated plate was determined by an empirical formulation. Such properties have been used as input parameters in the commercial software. The prediction for a splitter silencer with 1000 ㎜ length was compared with the experimental result. The numerical method is then applied to identify the effects of number of splitters, length of splitters, absorptive material density, and porosity of a perforated plate on the performance of the splitter silencers. As the number and length of splitter increases, the acoustic performance significantly increases. Although the increase of density of absorptive material also increase the acoustic performance, a change in the density over a certain level hardly affect it. The increase of porosity will enhance the performance especially at higher frequencies.