Low-frequency sound absorber allowing passing of fluid

Abstract

The invention provides a low-frequency sound absorber allowing passing of fluid. The low-frequency sound absorber allowing passing of fluid comprises a plurality of sound absorption units, and gaps allowing passing of fluid are formed among the sound absorption units. Each sound absorption unit comprises a hollow pipe body and plate bodies, wherein an opening extending in the axial direction of the pipe body is formed in the lateral wall of the pipe body, and the plate bodies are arranged at the two ends of the pipe body separately to close the two ends of the pipe body. According to the low-frequency sound absorber allowing passing of fluid, the gaps allowing passing of fluid are formed among the sound absorption units, so that application of the sound absorber to a pipeline system and other occasions is realized, absorption of sound waves is realized while fluid passes by, and low-frequency noise is reduced.

Description

technical field [0001] The invention relates to the technical field of sound wave processing, in particular to a low-frequency sound absorber allowing fluid to pass through. Background technique [0002] Low-frequency (<400Hz) sound waves widely exist in life, such as human speech and noise generated by equipment vibration. Therefore, the control and absorption of low-frequency sound waves has always been an important topic in acoustic engineering. Since the acoustic system is linear at a low sound pressure level (<120dB), the dissipation between the sound wave and the material is proportional to the square of the frequency, so the sound wave is difficult to dissipate in the low frequency band, and the absorption of the low frequency sound wave has always been is a long-term problem. [0003] Since the wavelength of sound waves in the air is very long (about 1m) at low frequencies, traditional porous sound-absorbing materials need at least a quarter-wavelength thickne...

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Problems solved by technology

[0003] Since the wavelength of sound waves in the air is very long (about 1m) at low frequencies, traditional porous sound-absorbing materials need at least a quarter-wavelength thickness to have significant absorption when supported by a wall, which will take up a lot of space. area, unbearable in limited space

At the same time, the waste of porous materials is not environmentally friendly, and it is inconvenient and unhealthy to use indoors.

[0004] In order to overcome the shortcomings of these traditional materials that cannot be ignored, people try to develop new subwavelength acoustic metamaterial low-frequency sound absorbers, but most of the metamaterial sound absorbers proposed so far require a rigid backing as a reflector to achieve a height greater than 80%. Efficient sound wave absorption, if there is no reflective plate, the maximum absorption is even difficult to exceed 50%

However, in the case of a reflective plate such as a rigid backing, the fluid will not be able to pass through the sound absorber, so most of these metamaterial sound absorbers cannot be used in piping systems

[0005] So far, there is only one kind of metamaterial sound absorber based on thin-film resonance unit in the prior art that allows fluid to pass through, which can be applied to piping systems, but the membrane is easily damaged, and the absorption of the membrane depends on the deformation of the membrane. In long-term use The problem of creep may occur, resulting in permanent deformation of the film, which affects the absorption performance of the film

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