Efficient broadband muffler pipe structure based on non-Bragg resonance

Abstract

The invention discloses an efficient broadband muffler pipe structure based on non-Bragg resonance, which is characterized in that the pipe wall of a tubular muffler pipe changes in periodic fluctuation, the change of each periodic fluctuation means that the inner wall of the pipe consists of adjacent concave-convex annular fluctuations, the width of each change period is equivalent to the size of the average radius of the muffler pipe, the incident wave frequency of the change period is audio, and the mode and direction of the incident wave are random; and the muffler pipe comprises more than five periods. By changing the parameters of the periodic pipe wall such as the number of the periods, the size of the fluctuation and the like, the muffling volume of the muffler pipe can be controlled. By selecting the period of the pipe wall, the muffling frequency band can be changed according to actual engineering demand. In actual engineering application, other resistive muffling methods can be compounded synchronously to improve the sound absorption effect. Moreover, the structure also can be used as an acoustic filter.

Description

technical field [0001] The invention relates to the band structure theory of the periodic waveguide, in particular to a pipeline muffler based on the non-Bragg resonance phenomenon. Background technique [0002] The problem of fluctuations in periodic waveguides has attracted extensive attention for a long time. The most classic research work in acoustics can be traced back to 1887. Rayleigh studied the propagation of sound waves in thin strings with periodic density changes, derived the propagation equation, and used the Hill method to study the solution of the equation. Until the 1970s, the rapid development of mathematical theory and calculation methods greatly promoted the research work in this area, and the propagation of sound waves and electromagnetic waves in periodic waveguides received extensive attention and in-depth research. [0003] In 1974, Nayfeh used the multi-scale expansion method to obtain the effective consistent expansion near the resonance region of t...

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Problems solved by technology

[0009] The purpose of the present invention is: in order to solve the problem of poor controllability of the noise reduction frequency band and noise reduction effect in the general noise reduction pipe, the present invention breaks through the limitation of the traditional expansion pipe silencer, and proposes a wide noise reduction bandwidth based on the non-Bragg resonance mechanism Muffler structure

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