A typical impedance silencer was installed in the ducts in order to inhibit the effect of air conditioning system on interior noise. The quantitative analysis of its acoustic transmission characteristics is an important part of noise reduction design for high-speed trains. The acoustic transmission model of a typical impedance silencer structure in the duct of air conditioning system was established and analyzed based on hybrid method of finite element and statistical energy analysis (FE-SEA). The transmission characteristics of the silencer between the frequencies of 80?3 150 Hz were predicted and calculated. The mechanics of peaks and valleys in the transmission loss curve were explained by calculating the acoustic modes based on the acoustic finite element method. The design projects of the silencer were optimally selected from the perspective of the acoustic performance and the actual situation of the project. Results show that the silencer in the air duct can effectively reduce noise, and its acoustic mode shape characteristics are the cause of its transmission loss peak/valley. The silencer resistive characteristics have a dominant effect on its acoustic transmission loss, and the optimal selection of acoustic absorbing material can improve the transmission loss up to about 18 dB. The resistance characteristics have relatively less effect on its transmission loss, and the optimal selection of the quantity and position of the absorption packages can improve its transmission loss by 4.1 dB. The impedance composite optimal selection can increase the transmission loss by 18.6 dB.
Fig.1Difference of interior noise spectrum when air condit-ioning switch
Fig.2Model of silencer in wind ducts of high-speed train
Fig.3Simulation model of silencer in wind ducts
Fig.4Model validation based on hybrid FE-SEA method
Fig.5Curve of transmission loss of silencer in wind ducts
Fig.6Acoustic modes of silencer in wind ducts
Fig.7Transmission loss and standard curves of silencer in wind ducts
吸声材料
ρ/（kg·m?3）
δ/（N·s·m?4）
Po
Rw/dB
矿渣棉
50
60 000
0.95
31.8
泡沫材料
55
87 000
0.97
26.8
玻璃棉
75
9 000
0.99
28.9
毛毡
50
45 000
0.92
25.3
玻璃纤维
5.5
20 000
0.94
25.8
Tab.2Parameters of selected sound absorption materials
Fig.8Analysis on influence of sound absorption materials’ selection on transmission loss of silencer in wind ducts
Fig.9Analysis on influence of sound absorption materials’ thickness on transmission loss of silencer in wind ducts
Fig.10Analysis on influence of sound packets’ number
Fig.11Analysis on influence of sound packets’ position （α=81°，β=71°，γ=62°）
Fig.12Comparison of structure of composite optimization with original model
Fig.13Comparison of transmission loss results of composite optimal selection with original model
[1]
FANG Z, JI Z L Numerical mode matching approach for acoustic attenuation prediction of double-chamber perforated tube dissipative silencers with mean flow[J]. Journal of Computational Acoustics, 2014, 22 (2): 1450004/1- 1450004/15
[2]
YU X, CHENG L Duct noise attenuation using reactive silencer with various internal configurations[J]. Journal of Sound and Vibration, 2015, 335: 229- 244
doi: 10.1016/j.jsv.2014.08.035
[3]
李明瑞, 邓国勇, 米永振, 等 基于响应面法的乘用车消声器声学性能优化[J]. 上海交通大学学报, 2017, 51 (09): 1031- 1035 LI Ming-rui, DENG Guo-yong, MI Yong-zhen, et al Acoustic performance optimization of the exhaust muffler for a car based on response surface method[J]. Journal of Shanghai Jiao Tong University, 2017, 51 (09): 1031- 1035
[4]
褚志刚, 匡芳, 高小新, 等 出口管过渡圆弧对抗性消声器性能的影响及应用[J]. 农业工程学报, 2015, 31 (6): 105- 112 CHU Zhi-gang, KUANG Fang, GAO Xiao-xin, et al Effects of outlet pipe transition circular arc on properties of reactive muffler and its application[J]. Transactions of the Chinese Society of Agricultural Engineering, 2015, 31 (6): 105- 112
[5]
褚志刚, 陆小华, 沈林邦, 等 抗性消声结构声腔模态对其消声特性的影响研究[J]. 内燃机工程, 2016, 37 (4): 147- 154 CHU Zhi-gang, LU Xiao-hua, SHEN Lin-bang, et al Effects of acoustic modes in chamber on acoustic attenuation characteristics of reactive silencing elements[J]. Chinese Internal Combustion Engine Engineering, 2016, 37 (4): 147- 154
[6]
杨亮, 季振林 阻性管道消声性能预测的边界元数值配点混合方法[J]. 振动工程学报, 2016, 29 (3): 498- 503 YANG Liang, JI Zhen-lin Acoustic attenuation prediction of dissipative ducts by combining boundary element method and numerical point collocation approach[J]. Journal of Vibration Engineering, 2016, 29 (3): 498- 503
[7]
杨亮, 季振林 消声器中高频传递损失计算的有限元-模态匹配混合方法[J]. 振动与冲击, 2017, (23): 243- 247 YANG Liang, JI Zhen-lin FE-mode maching hybridapproach for transmission loss prediction of silencers in mid-high frequency range[J]. Journal of Vibration and Shock, 2017, (23): 243- 247
[8]
杨亮, 季振林 穿孔消声器传递损失预测的快速多极混体边界元方法[J]. 哈尔滨工程大学学报, 2017, 38 (8): 1247- 1253 YANG Liang, JI Zhen-lin Transmission loss prediction of perforated silencers by fast multipole mixed-body boundary element method[J]. Journal of Harbin Engineering University, 2017, 38 (8): 1247- 1253
[9]
ZHU D D, JI Z L Transmission loss prediction of reactive silencers using 3-D time-domain CFD approach and plane wave decomposition technique[J]. Applied Acoustics, 2016, 112: 25- 31
doi: 10.1016/j.apacoust.2016.05.004
[10]
李恒, 郝志勇, 刘联鋆, 等 多腔穿孔消声器声学特性三维时域计算及评估[J]. 浙江大学学报: 工学版, 2015, 49 (5): 887- 892 LI Heng, HAO Zhi-yong, LIU Lian-yun, et al Three-dimensional time-domain computation and evaluation of acoustic performance of multi-cavity perforated muffler[J]. Journal of Zhejiang University: Engineering Science, 2015, 49 (5): 887- 892
[11]
范威, 郭立新 考虑气流影响的直通穿孔管消声器声学性能[J]. 东北大学学报: 自然科学版, 2016, 37 (11): 1655- 1659 FAN Wei, GUO Li-xin Acoustic performance of the straight-through perforated pipe silencer considering the effect of gas flow[J]. Journal of Northeasten University: Natural Science, 2016, 37 (11): 1655- 1659
[12]
JI L, HUANG Z. A case study of random boundary effects on the mid-frequency vibration of built-up systems [C] // Inter-Noise and Noise-Con Congress and Conference Proceedings. Sorrento: INCE, 2012: 377-382.
LEE I, SELAMET A, HUFF N T Impact of perforation impedance on the transmission loss of reactive and dissipative silencers[J]. Journal of the Acoustical Society of America, 2006, 120 (6): 3706- 3713
doi: 10.1121/1.2359703
[15]
项端祈. 空调系统消声与隔振设计[M]. 1版. 北京: 机械工业出版社, 2005.
[16]
ALLARD J F, ATALLA N. Propagation of sound in porous media: modeling sound absorbing materials [M]. 2nd ed. West Sussex: Wiley, 2009.
[17]
段翠云, 崔光, 刘培生 多孔吸声材料的研究现状与展望[J]. 金属功能材料, 2011, 18 (1): 60- 65 DUAN Cui-yun, CUI Guang, LIU Pei-sheng Present research and prospect of porous absorption materials[J]. Metallic Functional Materials, 2011, 18 (1): 60- 65
