A super-ventilated acoustic metamaterial silencer

Abstract

The present invention proposes a super-ventilated acoustic metamaterial soundproofing enclosure, comprising a soundproofing enclosure frame, which is a vertical rectangular frame structure. Each exposed surface of the frame is filled with at least one square tube to form a ventilated sound-absorbing wall. The square tubes extend through the interior and exterior of the soundproofing enclosure, and an acoustic metamaterial sound-absorbing patch is laid along the inner wall of the square tube. This inner wall of the acoustic metamaterial sound-absorbing patch forms a ventilation and noise reduction channel. A single acoustic metamaterial sound-absorbing patch comprises a patch housing, within which are disposed a plurality of metamaterial sound-absorbing units arranged in a horizontal matrix. Each metamaterial sound-absorbing unit comprises at least four metamaterial sound-absorbing structures, each of which is rotationally symmetrical about the center of the metamaterial sound-absorbing unit. A sound-absorbing inlet is provided on the top surface of the patch housing, corresponding to the center of each metamaterial sound-absorbing unit, and each metamaterial sound-absorbing structure is connected to the sound-absorbing inlet. The present invention can simultaneously solve the noise reduction and heat dissipation problems of noise-absorbing devices.

Description

Technical Field

[0001] The present invention relates to the technical field of sound-absorbing covers, and in particular to a super-ventilated acoustic metamaterial sound-absorbing cover. Background Art

[0002] Currently, most devices utilize traditional sound-absorbing materials such as cotton, foam, and porous panels to create soundproof walls around noise-generating devices. To dissipate the heat generated by the noise-generating devices, soundproofing panels are placed on only a few surfaces, leaving the remaining surfaces open. As a result, some sound is transmitted outward from the open surfaces, significantly reducing the sound absorption effect. Consequently, existing soundproofing devices cannot simultaneously achieve efficient ventilation and heat dissipation with efficient sound absorption. Acoustic metamaterials, similar to electromagnetic (including optical) metamaterials, are artificially fabricated subwavelength composite structures with negative equivalent mass density and negative equivalent modulus. Because their structural units are much smaller than the wavelength of sound waves, they possess many unique properties not found in natural materials, greatly expanding the applications and potential of acoustic materials. Effectively controlling low-frequency noise has always been a challenging problem due to its long sound waves, long propagation distances, and weak attenuation. The emergence of acoustic metamaterials addresses the shortcomings of traditional linear soundproofing materials in addressing low-frequency noise, demonstrating excellent low-frequency noise reduction performance. Summary of the Invention

[0003] In view of the problems existing in the above-mentioned prior art, the present invention aims to provide a super-ventilated acoustic metamaterial silencer to simultaneously solve the noise reduction and heat dissipation problems of the noise device.

[0004] To achieve the above objectives, the present invention proposes a super-ventilated acoustic metamaterial soundproofing cover, comprising a soundproofing cover frame, the soundproofing cover frame being a vertical rectangular frame structure, each exposed surface of the soundproofing cover frame being filled with at least one square tube to form a ventilated sound-absorbing wall; the square tube runs through the inside and outside of the soundproofing cover, and an acoustic metamaterial sound-absorbing patch is laid around the inner wall of the square tube, and the acoustic metamaterial sound-absorbing patch around the inner wall forms a ventilation and noise reduction channel;

[0005] A single acoustic metamaterial sound-absorbing patch includes a patch housing, within which are disposed a plurality of metamaterial sound-absorbing units arranged in a horizontal matrix, each of the metamaterial sound-absorbing units being tightly connected. A single metamaterial sound-absorbing unit includes at least four metamaterial sound-absorbing structures, each of which is rotationally symmetric about the center of the metamaterial sound-absorbing unit. A sound-absorbing inlet is disposed on the top surface of the patch housing at a position corresponding to the center of each metamaterial sound-absorbing unit, and each metamaterial sound-absorbing structure is in communication with the sound-absorbing inlet.

[0006] In the above scheme, the metamaterial sound-absorbing structure is a composite Helmholtz resonant cavity, consisting of two embedded resonant cavities connected in series. Each embedded resonant cavity has an annular channel, which encloses a rectangular cavity, and the rectangular cavity and the annular channel are connected. Acoustic energy can enter the Helmholtz resonant cavity within the sound-absorbing metamaterial patch, where it is resonated and dissipated, achieving the purpose of noise reduction.

[0007] In the above scheme, the metamaterial sound-absorbing structure is a labyrinthine structure with a zigzag channel inside that communicates with the sound-absorbing inlet. After entering the metamaterial's sound-absorbing unit, sound waves propagate within the narrow zigzag channel. When the sound wave frequency approaches the natural frequency of the structure, resonance occurs, causing violent oscillations within the channel. Thermoviscous and frictional losses between the sound wave and the channel walls convert the sound energy into heat and dissipate it, thus achieving a sound-absorbing effect. The zigzag structure, by folding the sound propagation path, can easily change the resonant frequency of the sound-absorbing unit.

[0008] In the above solution, the serrated channel is formed by means of a plurality of staggered serrations, and a channel spacing is provided between two adjacent serrations. The serrated channel is more conducive to sound absorption and noise reduction.

[0009] In the above solution, the interior of a single acoustic metamaterial sound-absorbing patch is composed of four acoustic metamaterial sound-absorbing units arranged in at least two rows and two columns. Through weak coupling between adjacent units, high-efficiency absorption of low-frequency sound can be achieved.

[0010] In the above scheme: the serrated channel is connected to the sound absorption inlet through a horizontally arranged sound absorption channel. When the width of the serrated channel is l, the width of the sound absorption inlet is k, the width of the sound absorption channel is a, the number of serrations in a single acoustic metamaterial sound absorption unit is n, and the serration wall thickness is w, the spacing between two adjacent serrations d = (k + w + lan * w) / n.

[0011] In the above solution, the thickness of the acoustic metamaterial sound-absorbing patch does not exceed 3 cm. The ultra-thin structure allows the fluid in the square tube to flow freely and almost perfectly, and realizes the miniaturization of the square tube, which is conducive to obtaining a larger ventilation ratio.

[0012] The beneficial effects of the present invention are as follows: sound wave energy can enter the metamaterial sound-absorbing units in the sound-absorbing metamaterial patch to be consumed, thereby achieving the purpose of sound attenuation, and then through weak coupling between adjacent metamaterial sound-absorbing units, quasi-perfect sound absorption or broadband sound absorption can be achieved; based on the sound absorption principle of acoustic metamaterials, the present invention builds a ventilated sound-absorbing metamaterial into a wall, and then uses this ventilated sound-absorbing wall to cover the noise device from all directions, thereby simultaneously solving the noise attenuation and heat dissipation problems of the noise device; through parameter adjustment, the ventilation area ratio can reach more than 80%, and the sound absorption rate can exceed 90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the present invention.

[0014] Figure 2 This is a schematic diagram of an acoustic metamaterial sound-absorbing patch installed inside a square tube.

[0015] Figure 3 This is a schematic diagram of the external structure of the acoustic metamaterial sound-absorbing patch.

[0016] Figure 4 This is a schematic diagram of the internal structure of an acoustic metamaterial sound-absorbing patch.

[0017] Figure 5 yes Figure 4 Schematic diagram of the structure of a single metamaterial sound absorption unit.

[0018] Figure 6 This is another schematic diagram of the internal structure of the acoustic metamaterial sound-absorbing patch.

[0019] Figure 7 yes Figure 6 Schematic diagram of the structure of a single metamaterial sound absorption unit. DETAILED DESCRIPTION

[0020] like Figure 1 As shown in FIG7 , a super-ventilated acoustic metamaterial silencer cover mainly consists of a silencer cover frame 1, a square tube 2 and an acoustic metamaterial sound-absorbing patch 3. Figure 2 The direction of the middle arrow is the ventilation direction of the square tube 2.

[0021] The silencer cover frame 1 is a vertical rectangular frame structure, and the cover is arranged outside the noise device.

[0022] Each exposed surface of the silencer frame 1 is filled with at least one square tube 2 to form a ventilation and sound-absorbing wall; the square tube 2 runs through the inside and outside of the silencer, and an acoustic metamaterial sound-absorbing patch 3 is laid around the inner wall of the square tube 2, and the circle of acoustic metamaterial sound-absorbing patches 3 on the inner wall forms a ventilation and noise reduction channel.

[0023] In order to save costs without affecting heat dissipation, you can choose to place ventilation and sound-absorbing walls on only part of the surfaces. However, in order to fully reduce noise and avoid sound leakage, other surfaces without ventilation and sound-absorbing walls can be replaced with hard backboards.

[0024] A single acoustic metamaterial sound-absorbing patch 3 includes a patch housing 33, within which are located multiple metamaterial sound-absorbing units 31 arranged in a horizontal matrix. Each metamaterial sound-absorbing unit 31 is tightly connected. Each metamaterial sound-absorbing unit 31 includes at least four metamaterial sound-absorbing structures 32, each of which is rotationally symmetric about the center of the metamaterial sound-absorbing unit 31.

[0025] A sound absorption inlet A is provided on the top surface of the patch housing 33 at a center position corresponding to each metamaterial sound absorption unit 31 , and each metamaterial sound absorption structure 32 is communicated with the sound absorption inlet A respectively.

[0026] Preferably, the metamaterial sound-absorbing structure 32 is a composite Helmholtz resonant cavity, which is formed by two embedded resonant cavities 34 connected in series. An annular channel D is provided within the embedded resonant cavity 34, and a rectangular cavity 35 is enclosed within the annular channel D. The rectangular cavity 35 communicates with the annular channel D. Acoustic energy can enter the Helmholtz resonant cavity within the sound-absorbing metamaterial patch, where it is resonated and dissipated, achieving the purpose of noise reduction.

[0027] Preferably, the metamaterial sound-absorbing structure 32 is a labyrinthine structure, internally provided with a zigzag channel B that communicates with the sound-absorbing inlet A. After entering the metamaterial sound-absorbing unit 31, sound waves propagate within the narrow zigzag channel B. When the sound wave frequency approaches the natural frequency of the structure, resonance occurs, causing violent oscillations within the channel. Thermoviscous and frictional losses between the sound wave and the channel walls convert the sound energy into heat and dissipate it, thus achieving a sound-absorbing effect. The zigzag structure, by folding the sound propagation path, can conveniently change the resonant frequency of the sound-absorbing unit.

[0028] Preferably, the serrated channel B is formed by means of a plurality of staggered serrations 321 , with a channel spacing provided between two adjacent serrations 321 . The serrated channel B is more conducive to sound absorption and noise reduction.

[0029] Preferably, the interior of a single acoustic metamaterial sound absorbing patch 3 is composed of four acoustic metamaterial sound absorbing units 31 arranged in at least two rows and two columns. Through weak coupling between adjacent units, efficient absorption of low-frequency sound can be achieved.

[0030] Preferably, the serrated channel B communicates with the sound absorption inlet A through a horizontally arranged sound absorption channel C. When the width of the serrated channel B is l, the width of the sound absorption inlet A is k, the width of the sound absorption channel C is a, the number of serrations 321 in a single acoustic metamaterial sound absorption unit 31 is n, and the wall thickness of the serrations 321 is w, the spacing d between two adjacent serrations 321 is (k+w+lan*w) / n.

[0031] Preferably, the thickness of the acoustic metamaterial sound-absorbing patch 3 does not exceed 3 cm. The ultra-thin structure can allow the fluid in the square tube 2 to flow freely almost perfectly and realize the miniaturization of the square tube 2, which is conducive to obtaining a larger ventilation ratio.

Claims

1. A super-ventilated acoustic metamaterial silencer, characterized by: The invention comprises a sound-absorbing cover frame (1), wherein the sound-absorbing cover frame (1) is a vertical rectangular frame structure, and each exposed surface of the sound-absorbing cover frame (1) is filled with at least one square tube (2) to form a ventilation sound-absorbing wall; the square tube (2) passes through the inside and outside of the sound-absorbing cover, and an acoustic metamaterial sound-absorbing patch (3) is laid on the inner wall of the square tube (2), and the acoustic metamaterial sound-absorbing patch (3) on the inner wall forms a ventilation noise reduction channel; A single acoustic metamaterial sound absorbing patch (3) comprises a patch housing (33), wherein a plurality of metamaterial sound absorbing units (31) arranged in a horizontal matrix are provided in the patch housing (33), and each metamaterial sound absorbing unit (31) is tightly connected; A single metamaterial sound absorbing unit (31) includes at least four metamaterial sound absorbing structures (32), each of the metamaterial sound absorbing structures (32) being rotationally symmetric about the center of the metamaterial sound absorbing unit (31); a sound absorbing inlet (A) is provided on the top surface of the patch housing (33) at a position corresponding to the center of each metamaterial sound absorbing unit (31), and each metamaterial sound absorbing structure (32) is respectively in communication with the sound absorbing inlet (A); The metamaterial sound absorbing structure (32) is a composite Helmholtz resonant cavity or a labyrinth structure; The composite Helmholtz resonant cavity is formed by two embedded resonant cavities (34) connected in series, wherein an annular channel (D) is provided in the embedded resonant cavity (34), a rectangular cavity (35) is wrapped in the annular channel (D), and the rectangular cavity (35) is communicated with the annular channel (D); a serrated channel (B) is provided inside the maze structure, and the serrated channel (B) is communicated with the sound absorption inlet (A).

2. The super-ventilated acoustic metamaterial sound-absorbing cover according to claim 1, characterized in that: The sawtooth channel (B) is formed by means of a plurality of staggered saw teeth (321), and a channel spacing is provided between two adjacent saw teeth (321).

3. The super-ventilated acoustic metamaterial sound-absorbing cover according to claim 1, characterized in that: The interior of a single acoustic metamaterial sound absorbing patch (3) is composed of four acoustic metamaterial sound absorbing units (31) arranged in at least two rows and two columns.

4. The super-ventilated acoustic metamaterial sound-absorbing cover according to claim 2, characterized in that: The serrated channel (B) is connected to the sound absorption inlet (A) through a horizontally arranged sound absorption channel (C). When the width of the serrated channel (B) is l, the width of the sound absorption inlet (A) is k, the width of the sound absorption channel (C) is a, the number of saw teeth (321) in a single acoustic metamaterial sound absorption unit (31) is n, and the wall thickness of the saw teeth (321) is w, the spacing between two adjacent saw teeth (321) is d=(k+w+lan*w) / n.

5. The super-ventilated acoustic metamaterial muffler according to claim 1, characterized in that: The thickness of the acoustic metamaterial sound-absorbing patch (3) does not exceed 3 cm.

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