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Attenuation of Blast Wave in a Duct with Expansion Region (Effects of Configuration, Porous Panel, and Acoustic Material)

  • M. Ishiguro
  • Y. TakakuraEmail author
Conference paper

Abstract

With recent increase of cars, the noise problem has been caused by exhaust sounds generated from exhaust pipes, which consist of weak pressure waves called blast waves. To diminish the noise, a silencer is installed in front of the exhaust pipe. In the present study, reflectors were installed in the high-pressure portion of the shock tube to generate blast waves, and as silencer models, three basic types of expansion regions were combined with four types of porous panels and acoustic material of glass wool. The pressure decay was investigated by transmission and reflection factors to the incident blast wave, together with pressure histories and high-speed movies by the shadowgraph method. As results, it was confirmed that the porous panel contributed to weaken the blast wave to some extent, while the acoustic material does greatly: the one-stage expansion model with a porous panel and glass wool recorded the highest decay of the peak over pressure for transmission and the two-stage expansion model with those showed the second highest. The acoustic material also contributed to decay of reflected shock waves propagating toward an upstream duct.

References

  1. 1.
    N. Sekine, S. Matsumura, K. Takayama, O. Ono, K. Itoh, Initiation and propagation of shock waves in the exhaust pipe of an internal combustion engines. Trans. Jpn. Soc. Mech. Eng., Ser. B 54(498), 527–531 (1988). https://doi.org/10.1299/kikaib.54.527 CrossRefGoogle Scholar
  2. 2.
    I. Sakamoto, F. Higashino, K. Higuchi, Decay of pressure waves passing through expansion region in a two dimensional duct. Trans. Jpn. Soc. Mech. Eng., Ser. B 67(657), 1170–1176 (2001). https://doi.org/10.1299/kikaib.67.1170 CrossRefGoogle Scholar
  3. 3.
    T. Namiki, R. Shimamura, K. Ohki, Y. Takakura, Rupturing device and generation characteristics of shock and blast waves, in Proceedings of the Symposium on Shock Waves in Japan, 2014, p-04Google Scholar
  4. 4.
    N. Sekine, O. Onodera, K. Takayama, Study of silencer characteristics in a gas flow with shock wave (1st report, propagation of shock wave in the silencer). Trans. Jpn. Soc. Mech. Eng., Ser. B 60(575), 2315–2320 (1994). https://doi.org/10.1299/kikaib.60.2315 CrossRefGoogle Scholar
  5. 5.
    M. Ishiguro, K. Shinkai, R. Shimamura, H. Gunzi, Y. Takakura, Attenuation of Blast Wave by Expansion Region in a Duct (Effect of Expansion Configuration and Acoustic Material), FLUCOME2015, paper No.32 (2015)Google Scholar
  6. 6.
    M. Ishiguro, K. Shinkai, R. Shimamura, H. Gunji, Y. Takakura, Attenuation effect of expansion configuration and acoustic material on propagation of blast waves in a duct. J. Flow Control Measur. Vis. 4(3), 79–92 (2016). https://doi.org/10.4236/jfcmv.2016.43008 CrossRefGoogle Scholar
  7. 7.
    M. Ishiguro, Y. Takakura, Attenuation of Blast Waves in a Duct (Effect of expansion region configuration and acoustic materials), Trans. Jpn. Soc. Mech. Eng., G0500202 (2016)Google Scholar
  8. 8.
    JIS (Japanese Industrial Standards) B 8379 Silencer for air pressure (2009)Google Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Graduate School of Tokai UniversityHiratsukaJapan

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