Author : Xiaofeng Shi
Publisher :
ISBN 13 :
Total Pages : 129 pages
Book Rating : 4.:/5 (973 download)
Book Synopsis A Study of the Effect of Periodic Structure on the Attenuation Performance of the Mufflers by : Xiaofeng Shi
Download or read book A Study of the Effect of Periodic Structure on the Attenuation Performance of the Mufflers written by Xiaofeng Shi and published by . This book was released on 2016 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: The expansion chamber muffler is an effective device for noise reduction in duct systems. The transmission loss of the single expansion muffler has a periodic character that is often used for the periodic noise control. The Bloch wave theory and the transfer matrix method are used to study the wave propagation in periodic expansion chamber mufflers and the dispersion characteristics are examined. The theory is validated against finite element method simulation. Compared to a single expansion chamber muffler, the stopbands of the finite periodic structure is mainly due to its dispersion characteristics. With different configuration, the results indicate that the periodic structure can enhance the transmission loss within a narrower frequency range or change effective noise control frequency ranges with different distance between mufflers. Because of the high acoustic resistance and low mass reactance due to the sub-millimeter perforation, the micro-perforated muffler can provide considerable sound attenuation of duct noise. The wave propagation in periodic micro-perforated mufflers is studied theoretically, numerically and experimentally. This study indicates that the combination of the Bragg reflection due to the periodic structure and the resonance of the micro-perforated muffler can result in different transmission loss. The proposed periodic placement of micro-perforated mufflers can provide lower frequency noise control within a broader frequency range or enhance transmission loss around the resonant frequency.