Broadband muffler pipe of adjustable resonant frequency based Helmholtz resonator

Abstract

The invention discloses a broadband muffler pipe of adjustable resonant frequency based Helmholtz resonator. The pipe comprises an upper surface and a lower surface arranged on the pipe body in a parallel manner. The upper surface and the lower surface are both provided with a plurality of dimensionally fixed cavities arranged symmetrically along the main pipe body with the cavities at equal intervals. A pair of solid baffle plates is arranged between each cavity and the main pipe body. A throat tube with variable positions and cross-sections is formed between two solid baffle plates. The eccentricity and the cross-section of the throat tube vary according to the movement of the solid baffle plates from the left to the right. The broadband muffler pipe of adjustable resonant frequency based Helmholtz resonator of the invention can improve the cavity length without changing the volume of the resonator cavity so that the size of the cavity on the acoustic wave transmission path is close to an acoustic wave length. With the invention, the action frequency of the resonator is changed by breaking the application conditions of a lumped parameter system and changing the cross-section size of the internal throat tube and its distance to the center of the cavity.

Description

technical field [0001] The invention relates to a wide-band muffler pipeline based on a Helmholtz resonator with adjustable resonance frequency, and belongs to the field of acoustics. Background technique [0002] Traditional pipeline noise reduction equipment such as the Helmholtz resonator pipeline based on resonance noise reduction is equivalent to a resistant silencer, consisting of a throat and a cavity. The air in the throat is equivalent to the sound quality, and the cavity is equivalent to the spring, which are respectively analogous to the inductance and capacitance in the electrical circuit. When the sound wave frequency is closest to the natural frequency of the muffler, the noise reduction is the largest, and it acts as an acoustic filter. However, the cavity length of this kind of resonator is usually much smaller than the wavelength of the sound wave, and the resonant frequency obtained by treating it as a concentrated parameter does not change with the size. ...

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Problems solved by technology

However, the cavity length of this kind of resonator is usually much smaller than the wavelength of the sound wave, and the resonant frequency obtained by treating it as a concentrated parameter does not change with the size. Once the sound-absorbing pipe is made, it cannot be used for other purposes.

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