Transversal modes and acoustic attenuation characteristics of rectangular and oval silencers with perforated tube

2012 ◽  
Vol 131 (4) ◽  
pp. 3212-3212
Author(s):  
Zhi Fang ◽  
Zhenlin Ji
Keyword(s):  
Acoustic Attenuation ◽  
Attenuation Characteristics ◽  
Perforated Tube

ACOUSTIC ATTENUATION CHARACTERISTICS OF STRAIGHT-THROUGH PERFORATED TUBE SILENCERS AND RESONATORS

2008 ◽  
Vol 16 (03) ◽  
pp. 361-379 ◽  
Author(s):  
Z. L. JI
Keyword(s):  
Performance Prediction ◽  
Transmission Loss ◽  
Three Dimensional ◽  
Geometrical Parameters ◽  
Mean Flow ◽  
Acoustic Attenuation ◽  
One Dimensional ◽  
The One ◽  
Attenuation Characteristics ◽  
Perforated Tube

The one-dimensional analytical solutions are derived and three-dimensional substructure boundary element approaches are developed to predict and analyze the acoustic attenuation characteristics of straight-through perforated tube silencers and folded resonators without mean flow, as well as to examine the effect of nonplanar waves in the silencers and resonators on the acoustic attenuation performance. Comparisons of transmission loss predictions with the experimental results for prototype straight-through perforated tube silencers demonstrated that the three-dimensional approach is needed for accurate acoustic attenuation performance prediction at higher frequencies, while the simple one-dimensional theory is sufficient at lower frequencies. The BEM is then used to investigate the effects of geometrical parameters on the acoustic attenuation characteristics of straight-through perforated tube silencers and folded resonators in detail.

Application of a Discrete Transfer Matrix Method in Analysis of Acoustic Attenuation Performance of Complex Perforated Pipe Mufflers

2013 ◽  
Vol 419 ◽  
pp. 140-144
Author(s):  
Huo Rui ◽  
Meng Bei ◽  
Zhang Lei
Keyword(s):  
Transfer Matrix ◽  
Transmission Loss ◽  
Influential Factors ◽  
Calculation Formula ◽  
Acoustic Attenuation ◽  
Noise Elimination ◽  
Discrete Method ◽  
Factors Analysis ◽  
Perforated Pipe ◽  
Perforated Tube

The article is about an application of a discrete method for analyzing acoustic attenuation performance of perforated tube mufflers. Acoustic transfer matrix of a tiny perforated tube section which contains one single hole is deduced based on basic hydromechanics equations. Then the work is developed into a general formula for resolving sound transmission loss of one perforated silencer unit consisting of multiple parallel perforated pipes. Result of the calculation formula is compared with that of acoustic finite element method. One more example is presented on influential factors analysis for noise elimination performance of a practical complex perforation muffler.

scholarly journals Influence of perforation and sound-absorbing material filling on acoustic attenuation performance of three-pass perforated mufflers

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401774801 ◽  
Author(s):  
Hongpu Huang ◽  
Zhenlin Ji ◽  
Zhuoliang Li
Keyword(s):  
Finite Element Method ◽  
Transmission Loss ◽  
The Finite Element Method ◽  
Frequency Range ◽  
Acoustic Attenuation ◽  
Pressure Drops ◽  
Outlet Tube ◽  
Middle Chamber ◽  
Absorbing Material ◽  
Perforated Tube

The finite element method is employed to calculate the transmission loss of three-pass perforated reactive and hybrid mufflers. The effects of perforated tubes and bulkheads on the transmission loss of three-pass reactive mufflers are investigated numerically. Two types of hybrid mufflers are considered, and the effects of sound-absorbing material filling and packed outlet tube on the acoustic attenuation performance of mufflers are analyzed. The perforations of the tubes and bulkheads and sound-absorbing material filling are demonstrated to have significant influence on the acoustic attenuation behaviors of the mufflers. The perforation of the tubes and bulkheads may shift the resonance from the low- to middle-frequency range. The sound-absorbing material filling in the middle chamber improves the acoustic attenuation performance at middle to higher frequencies and provides a relatively flat and broadband acoustic attenuation. It is found that the solid inlet or outlet tube replacing the perforated tube and sound-absorbing material filling in the middle chamber increases the pressure drops, while the rest configurations change the pressure drops slightly.

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