A folding and coiled channel acoustic silencer

Abstract

The present invention discloses a folding and coiled-channel acoustic muffler, which relates to the technical field of noise vibration and control and solves the problem that the channel length of the existing muffler is getting longer. The present invention includes a plurality of sound-absorbing units arranged in a matrix; each sound-absorbing unit is formed by the cooperation of a first coiled channel and a second coiled channel. A plurality of sound-absorbing channels are arranged in both the first coiled channel and the second coiled channel, and the plurality of sound-absorbing channels are connected in a serpentine shape front and back. By arranging the plurality of sound-absorbing channels, the transmission path of sound waves is extended to achieve the low-frequency sound-absorbing effect. The structure of the present invention is simple and highly adjustable. The sound absorption at the target frequency band is achieved by adjusting the structural parameters of the muffler. And on the premise of not losing the acoustic performance, the shape of the sample can be changed in a folded form to meet the requirements of various scenarios.

Description

Technical Field

[0001] The present invention relates to the technical field of noise, vibration and control, and particularly to a foldable coiled channel acoustic muffler. Background Art

[0002] Noise and vibration control is an important research topic in the field of acoustics, and has important research value and practical significance in the daily production and life of human society. In today's society, the noise pollution caused by various noise sources has become increasingly serious, and has become a new environmental problem that cannot be ignored globally. Noise pollution is known as one of the four major pollutions today, together with water pollution, air pollution and solid waste pollution. Environmental noise in life can reduce our quality of life and work efficiency, and even endanger people's physical health. Research shows that long-term noise pollution can cause headaches and dizziness, and even more seriously, it can induce cardiovascular and cerebrovascular diseases; in production and scientific research activities, excessive vibration will seriously affect the safety and life of mechanical parts in the normal working environment, greatly reducing their reliability. Therefore, we can install sound-absorbing materials in buildings to reduce noise problems or improve the indoor auditory experience. Given the diverse significance of sound-absorbing materials, the development of high-performance broadband sound-absorbing materials has always been a topic of widespread concern. However, for traditional materials, such as porous absorption foams, the material properties have inherent limitations, resulting in a low tunability of the absorption spectrum.

[0003] In recent years, the emergence of acoustic metamaterials has broken this limitation and completely achieved the goal of "controlling large wavelengths with small sizes". Common acoustic metamaterial elements can be Helmholtz resonators, thin-film acoustic metamaterials, micro-perforated plates, etc.; by adjusting the resonance frequency and oscillation intensity, in principle, the impedance matching conditions can be achieved by designing the geometric shape and parameters of the absorber. With the discovery of scientific research by people, coiled channel acoustic metamaterials have been proven to support high absorption and have characteristics such as low sample thickness and easy adjustment of the absorption frequency band, and are one of the most promising metamaterials in the future. The channel length is a key parameter of coiled channel acoustic metamaterials, and the longer the channel length, the better the corresponding low-frequency acoustic performance. However, in the face of an increasingly long channel length, the size of the sample also increases accordingly, which does not conform to the design concept of acoustic metamaterials and is one of the problems that need to be urgently solved in current scientific research. Summary of the Invention

[0004] In order to solve the problem of the increasing length of the muffler channel mentioned above, the present invention hereby provides a folded and coiled channel acoustic muffler. The folded and coiled channel acoustic muffler proposed by the present invention has a simple structure and strong adjustability. By simply adjusting the structural parameters of the muffler, sound absorption at the target frequency band can be achieved. And without loss of acoustic performance, the shape of the sample can be changed in a folded form to meet the requirements of various scenarios, so as to solve the problem of the flexibility of the current acoustic metamaterial structure.

[0005] The present invention provides a folded and coiled channel acoustic muffler, which specifically includes a plurality of muffling units arranged in a matrix; each muffling unit is formed by the cooperation of a first coiled channel and a second coiled channel. A plurality of sound absorption channels are arranged in both the first coiled channel and the second coiled channel, and the plurality of sound absorption channels are connected in a serpentine shape front and back. By setting the plurality of sound absorption channels, the transmission path of sound waves is extended to achieve the low-frequency sound absorption effect.

[0006] Furthermore, the overall channel lengths of the first coiled channel and the second coiled channel are calculated according to the frequency corresponding to the target resonance peak, and the calculation formula is

[0007]

[0008] where f m - the frequency corresponding to the resonance peak, m - the mode, c - the speed of sound, L - the coiled channel length.

[0009] Furthermore, the heights between the plurality of first coiled channels are all different, and the heights between the plurality of second coiled channels are also all different.

[0010] Furthermore, the lengths of the plurality of sound absorption channels arranged inside the same first coiled channel or the same second coiled channel increase in sequence, while the width and height remain unchanged.

[0011] Furthermore, a plurality of connectors are also arranged on the first coiled channel and the second coiled channel. Different sound absorption channels inside the same coiled channel are connected by the connectors; the height of the plurality of connectors arranged inside the same coiled channel is the same as the length of the previous sound absorption channel connected thereto, and the width and length of the connectors remain unchanged.

[0012] Furthermore, the first coiled channel includes a first coiled channel, a third coiled channel, a fifth coiled channel, and a seventh coiled channel, and the first coiled channel, the third coiled channel, the fifth coiled channel, and the seventh coiled channel are arranged in sequence from top to bottom and from left to right.

[0013] Further, the second coiling channels include a second coiling channel, a fourth coiling channel, a sixth coiling channel, and an eighth coiling channel. The second coiling channel is arranged at the center of the first coiling channel, the fourth coiling channel is arranged at the center of the third coiling channel, the sixth coiling channel is arranged at the center of the fifth coiling channel, and the eighth coiling channel is arranged at the center of the seventh coiling channel.

[0014] Further, the folded coiling channel acoustic silencer further includes a partition board, and the partition board wraps a plurality of first coiling channels and a plurality of second coiling channels inside.

[0015] Further, the thickness of the partition board is 2 mm.

[0016] Further, a channel opening is provided on each first coiling channel and each second coiling channel.

[0017] The beneficial effects of the folded coiling channel acoustic silencer of the present invention are as follows:

[0018] (1) For the folded coiling channel acoustic silencer of the present invention, the sound absorption coefficient can reach more than 0.5 in the range of 189 Hz - 225 Hz, and the highest sound absorption coefficient can reach 0.9, realizing low-frequency broadband sound absorption;

[0019] (2) For the folded coiling channel acoustic silencer of the present invention, the structure is simple and easy to adjust. The shape can be changed by folding, and the sound absorption bandwidth can be broadened by adding more coiling channels later, which is widely used in industrial production;

[0020] (3) For the folded coiling channel acoustic silencer of the present invention, there is no specific requirement for the material, and it can be realized only with a solid rigid structure. Description of the Drawings

[0021] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0022] In the drawings:

[0023] Figure 1 is a schematic diagram of the folding principle of the folded coiling channel acoustic silencer of the present invention;

[0024] Figure 2 is a top view structural schematic diagram of a single coiling channel of the folded coiling channel acoustic silencer of the present invention;

[0025] Figure 3 is a side view structural schematic diagram of a single coiling channel of the folded coiling channel acoustic silencer of the present invention;

[0026] Figure 4 is a 1 / 4 overall structure diagram of a folding and coiled channel acoustic muffler according to the present invention;

[0027] Figure 5 is a schematic overall structure diagram of a folding and coiled channel acoustic muffler according to the present invention;

[0028] Figure 6 is a comparison diagram of the acoustic performance before and after folding of a folding and coiled channel acoustic muffler according to the present invention;

[0029] Figure 7 is a diagram of the sound absorption coefficient of each coiled channel of a folding and coiled channel acoustic muffler according to the present invention;

[0030] Figure 8 is a sound absorption effect diagram of a folding and coiled channel acoustic muffler according to the present invention;

[0031] Wherein: 1 - first sound absorption channel, 2 - second sound absorption channel, 3 - third sound absorption channel, 4 - fourth sound absorption channel, 5 - fifth sound absorption channel, 6 - sixth sound absorption channel, 7 - seventh sound absorption channel, 8 - eighth sound absorption channel, 9 - ninth sound absorption channel, 10 - first coiled channel, 11 - second coiled channel, 12 - third coiled channel, 13 - fourth coiled channel, 14 - fifth coiled channel, 15 - sixth coiled channel, 16 - seventh coiled channel, 17 - eighth coiled channel, 18 - partition, 19 - channel outlet, 20 - connecting body, H - muffler structure height, h - coiled channel height, W - sound absorption channel length, w - connecting body height between sound absorption channels, E - muffler structure length and width. Specific Embodiments

[0032] The following further elaborates on the specific embodiments of the present invention with reference to the accompanying drawings:

[0033] Specific Embodiment 1: Refer to Figures 1-8 Specifically illustrate this embodiment. A folding and coiled channel acoustic muffler described in this embodiment specifically includes a plurality of muffling units, and the plurality of muffling units are arranged in a matrix; each muffling unit is formed by the cooperation of a first coiled channel and a second coiled channel, and a first coiled channel is sleeved outside a second coiled channel; a plurality of sound absorption channels are arranged in both the first coiled channel and the second coiled channel, and the plurality of sound absorption channels are connected in a serpentine shape front and back. By arranging the plurality of sound absorption channels, the transmission path of sound waves is extended to achieve a low-frequency sound absorption effect. The plurality of first coiled channels and the plurality of second coiled channels are integrally folded into a cuboid shape, and the performance of the coiled channels does not change before and after folding, and the acoustic performance of the coiled channels will not be lost after the structural shape is changed. For example Figure 6As shown; the overall structure of the muffler is a cuboid with overall dimensions of E*E*H, where E is 102 mm and H is 50 mm.

[0034] For the selection of the overall length of the coiled channel, it is calculated according to the frequency corresponding to the target resonance peak, and the calculation formula is as follows:

[0035]

[0036] In the formula: f m - The frequency corresponding to the resonance peak; m - Mode; c - Sound speed; L - Coiled channel length.

[0037] On the premise of ensuring a certain overall length of the coiled channel, by changing the length of the internal sound-absorbing channel and gradually increasing the length of the internal sound-absorbing channel, heat loss is generated during the process of the medium under thermoviscous action and compression-expansion, so as to increase the sound energy loss.

[0038] Therefore, in terms of the external dimension design, the height of the first coiled channel is lower than that of the second coiled channel, and the upper surfaces of the first coiled channel and the second coiled channel are flush; the heights between several first coiled channels are all different, and the heights between several second coiled channels are also all different, so that the overall length of the channel corresponding to each coiled channel is different, and each coiled channel corresponds to an absorption frequency.

[0039] The lengths of several sound-absorbing channels arranged inside the same coiled channel increase in sequence, and the width and height remain unchanged. This is to generate heat loss during the process of the medium under thermoviscous action and compression-expansion by gradually increasing the length of the sound-absorbing channel, so as to increase the sound energy loss.

[0040] As Figure 2 shown, it is a schematic structural diagram of the first coiled channel. Inside the first coiled channel, there are a first sound-absorbing channel 1, a second sound-absorbing channel 2, a third sound-absorbing channel 3, a fourth sound-absorbing channel 4, a fifth sound-absorbing channel 5, a sixth sound-absorbing channel 6, a seventh sound-absorbing channel 7, an eighth sound-absorbing channel 8, and a ninth sound-absorbing channel 9. The above-mentioned sound-absorbing channels are connected in a serpentine shape through a connecting body 20 in sequence. Considering the regularity of the overall structure, the ninth sound-absorbing channel 9 of the first coiled channel is folded into an L shape; similarly, inside the second coiled channel, there are a first sound-absorbing channel 1, a second sound-absorbing channel 2, a third sound-absorbing channel 3, a fourth sound-absorbing channel 4, and a fifth sound-absorbing channel 5. The above-mentioned sound-absorbing channels are connected in a serpentine shape through a connecting body 20 in sequence. Considering the regularity of the overall structure, the fifth sound-absorbing channel 5 of the second coiled channel is folded into an L shape.

[0041] The first coiling channel and the second coiling channel are also provided with a number of connectors 20. Different sound-absorbing channels within the same coiling channel are connected by the connectors 20. The heights of the a number of connectors 20 provided within the same coiling channel are the same as the lengths of the previous sound-absorbing channels they connect, so that the transmission of sound waves can be more uniform during the transition. The widths and lengths of the connectors 20 within the same coiling channel remain unchanged.

[0042] The first coiling channel includes a first coiling channel 10, a third coiling channel 12, a fifth coiling channel 14, and a seventh coiling channel 16. The first coiling channel 10, the third coiling channel 12, the fifth coiling channel 14, and the seventh coiling channel 16 are arranged in sequence from top to bottom and from left to right.

[0043] The second coiling channel includes a second coiling channel 11, a fourth coiling channel 13, a sixth coiling channel 15, and an eighth coiling channel 17. The second coiling channel 11 is arranged at the center of the first coiling channel 10, the fourth coiling channel 13 is arranged at the center of the third coiling channel 12, the sixth coiling channel 15 is arranged at the center of the fifth coiling channel 14, and the eighth coiling channel 17 is arranged at the center of the seventh coiling channel 16, thereby forming 4 sound-absorbing units. The 4 sound-absorbing units are arranged in sequence from top to bottom and from left to right.

[0044] The folded coiling channel acoustic muffler further includes a partition 18. The partition 18 wraps a number of first coiling channels and a number of second coiling channels inside. The upper surfaces and side surfaces of a number of first coiling channels are in contact with the partition 18, and the upper and lower surfaces of a number of second coiling channels are in contact with the partition 18. The thickness of the partition 18 is 2 mm.

[0045] Each first coiling channel is provided with a channel opening 19, and each second coiling channel is provided with a channel opening 19. The number of channel openings 19 is 8, and the opening size is 3.6 mm * 6 mm.

[0046] The channel opening 19 passes through the partition 18 and protrudes above the end face of the muffler. The opening height is 2 mm. All the channel openings 19 face the same direction, and sound waves enter the coiling channel through the channel openings 19.

[0047] In this embodiment, the specific parameter designs of each coiling channel and the internal sound-absorbing channels are as follows:

[0048] The first coiled channel 10, the channel length of the first sound-absorbing channel 1 is 3.6 mm, the height is 29 mm, the length of the connecting body 20 between the first sound-absorbing channel 1 and the second sound-absorbing channel 2 is 2 mm, and the height is 3.6 mm; the channel length of the second sound-absorbing channel 2 is 6 mm, the height is 29 mm, the length of the connecting body 20 between the second sound-absorbing channel 2 and the third sound-absorbing channel 3 is 2 mm, and the height is 6 mm; the channel length of the third sound-absorbing channel 3 is 8.7 mm, the height is 29 mm, the length of the connecting body 20 between the third sound-absorbing channel 3 and the fourth sound-absorbing channel 4 is 2 mm, and the height is 8.7 mm; the channel length of the fourth sound-absorbing channel 4 is 11.5 mm, the height is 29 mm, the length of the connecting body 20 between the fourth sound-absorbing channel 4 and the fifth sound-absorbing channel 5 is 2 mm, and the height is 11.5 mm; the channel length of the fifth sound-absorbing channel 5 is 13.8 mm, the height is 29 mm, the length of the connecting body 20 between the fifth sound-absorbing channel 5 and the sixth sound-absorbing channel 6 is 2 mm, and the height is 13.8 mm; the channel length of the sixth sound-absorbing channel 6 is 16.6 mm, the height is 29 mm, the length of the connecting body 20 between the sixth sound-absorbing channel 6 and the seventh sound-absorbing channel 7 is 2 mm, and the height is 16.6 mm; the channel length of the seventh sound-absorbing channel 7 is 19 mm, the height is 29 mm, the length of the connecting body 20 between the seventh sound-absorbing channel 7 and the eighth sound-absorbing channel 8 is 2 mm, and the height is 19 mm; the channel length of the eighth sound-absorbing channel 8 is 24.5 mm, the height is 29 mm, the length of the connecting body 20 between the eighth sound-absorbing channel 8 and the ninth sound-absorbing channel 9 is 2 mm, and the height is 24.5 mm; the channel length of the ninth sound-absorbing channel 9 is 30 mm, and the height is 29 mm.

[0049] The second coiled channel 11, the channel length of the first sound-absorbing channel 1 is 3.6 mm, the height is 46 mm, the length of the connecting body 20 between the first sound-absorbing channel 1 and the second sound-absorbing channel 2 is 2 mm, and the height is 3.6 mm; the channel length of the second sound-absorbing channel 2 is 7.8 mm, the height is 46 mm, the length of the connecting body 20 between the second sound-absorbing channel 2 and the third sound-absorbing channel 3 is 2 mm, and the height is 7.8 mm; the channel length of the third sound-absorbing channel 3 is 10.6 mm, the height is 46 mm, the length of the connecting body 20 between the third sound-absorbing channel 3 and the fourth sound-absorbing channel 4 is 2 mm, and the height is 10.6 mm; the channel length of the fourth sound-absorbing channel 4 is 18 mm, the height is 46 mm, the length of the connecting body 20 between the fourth sound-absorbing channel 4 and the fifth sound-absorbing channel 5 is 2 mm, and the height is 18 mm; the channel length of the fifth sound-absorbing channel 5 is 28 mm, and the height is 46 mm.

[0050] The third curling channel 12, the channel length of the first sound-absorbing channel 1 is 3.6 mm, and the height is 28.5 mm. The length of the connecting body 20 between the first sound-absorbing channel 1 and the second sound-absorbing channel 2 is 2 mm, and the height is 3.6 mm; the channel length of the second sound-absorbing channel 2 is 6 mm, and the height is 28.5 mm. The length of the connecting body 20 between the second sound-absorbing channel 2 and the third sound-absorbing channel 3 is 2 mm, and the height is 6 mm; the channel length of the third sound-absorbing channel 3 is 8.7 mm, and the height is 28.5 mm. The length of the connecting body 20 between the third sound-absorbing channel 3 and the fourth sound-absorbing channel 4 is 2 mm, and the height is 8.7 mm; the channel length of the fourth sound-absorbing channel 4 is 11.5 mm, and the height is 28.5 mm. The length of the connecting body 20 between the fourth sound-absorbing channel 4 and the fifth sound-absorbing channel 5 is 2 mm, and the height is 11.5 mm; the channel length of the fifth sound-absorbing channel 5 is 13.8 mm, and the height is 28.5 mm. The length of the connecting body 20 between the fifth sound-absorbing channel 5 and the sixth sound-absorbing channel 6 is 2 mm, and the height is 13.8 mm; the channel length of the sixth sound-absorbing channel 6 is 16.6 mm, and the height is 28.5 mm. The length of the connecting body 20 between the sixth sound-absorbing channel 6 and the seventh sound-absorbing channel 7 is 2 mm, and the height is 16.6 mm; the channel length of the seventh sound-absorbing channel 7 is 19 mm, and the height is 28.5 mm. The length of the connecting body 20 between the seventh sound-absorbing channel 7 and the eighth sound-absorbing channel 8 is 2 mm, and the height is 19 mm; the channel length of the eighth sound-absorbing channel 8 is 24.5 mm, and the height is 28.5 mm. The length of the connecting body 20 between the eighth sound-absorbing channel 8 and the ninth sound-absorbing channel 9 is 2 mm, and the height is 24.5 mm; the channel length of the ninth sound-absorbing channel 9 is 30 mm, and the height is 28.5 mm.

[0051] The fourth curling channel 13, the channel length of the first sound-absorbing channel 1 is 3.6 mm, and the height is 45 mm. The length of the connecting body 20 between the first sound-absorbing channel 1 and the second sound-absorbing channel 2 is 2 mm, and the height is 3.6 mm; the channel length of the second sound-absorbing channel 2 is 7.8 mm, and the height is 45 mm. The length of the connecting body 20 between the second sound-absorbing channel 2 and the third sound-absorbing channel 3 is 2 mm, and the height is 7.8 mm; the channel length of the third sound-absorbing channel 3 is 10.6 mm, and the height is 45 mm. The length of the connecting body 20 between the third sound-absorbing channel 3 and the fourth sound-absorbing channel 4 is 2 mm, and the height is 10.6 mm; the channel length of the fourth sound-absorbing channel 4 is 18 mm, and the height is 45 mm. The length of the connecting body 20 between the fourth sound-absorbing channel 4 and the fifth sound-absorbing channel 5 is 2 mm, and the height is 18 mm; the channel length of the fifth sound-absorbing channel 5 is 28 mm, and the height is 45 mm.

[0052] The fifth curling channel 14, the first sound absorption channel 1 has a channel length of 3.6 mm and a height of 27 mm. The connecting body 20 between the first sound absorption channel 1 and the second sound absorption channel 2 has a length of 2 mm and a height of 3.6 mm. The second sound absorption channel 2 has a channel length of 6 mm and a height of 27 mm. The connecting body 20 between the second sound absorption channel 2 and the third sound absorption channel 3 has a length of 2 mm and a height of 6 mm. The third sound absorption channel 3 has a channel length of 8.7 mm and a height of 27 mm. The connecting body 20 between the third sound absorption channel 3 and the fourth sound absorption channel 4 has a length of 2 mm and a height of 8.7 mm. The fourth sound absorption channel 4 has a channel length of 11.5 mm and a height of 27 mm. The connecting body 20 between the fourth sound absorption channel 4 and the fifth sound absorption channel 5 has a length of 2 mm and a height of 11.5 mm. The fifth sound absorption channel 5 has a channel length of 13.8 mm and a height of 27 mm. The connecting body 20 between the fifth sound absorption channel 5 and the sixth sound absorption channel 6 has a length of 2 mm and a height of 13.8 mm. The sixth sound absorption channel 6 has a channel length of 16.6 mm and a height of 27 mm. The connecting body 20 between the sixth sound absorption channel 6 and the seventh sound absorption channel 7 has a length of 2 mm and a height of 16.6 mm. The seventh sound absorption channel 7 has a channel length of 19 mm and a height of 27 mm. The connecting body 20 between the seventh sound absorption channel 7 and the eighth sound absorption channel 8 has a length of 2 mm and a height of 19 mm. The eighth sound absorption channel 8 has a channel length of 24.5 mm and a height of 27 mm. The connecting body 20 between the eighth sound absorption channel 8 and the ninth sound absorption channel 9 has a length of 2 mm and a height of 24.5 mm. The ninth sound absorption channel 9 has a channel length of 30 mm and a height of 27 mm.

[0053] The sixth curling channel 15, the first sound absorption channel 1 has a channel length of 3.6 mm and a height of 43 mm. The connecting body 20 between the first sound absorption channel 1 and the second sound absorption channel 2 has a length of 2 mm and a height of 3.6 mm. The second sound absorption channel 2 has a channel length of 7.8 mm and a height of 43 mm. The connecting body 20 between the second sound absorption channel 2 and the third sound absorption channel 3 has a length of 2 mm and a height of 7.8 mm. The third sound absorption channel 3 has a channel length of 10.6 mm and a height of 43 mm. The connecting body 20 between the third sound absorption channel 3 and the fourth sound absorption channel 4 has a length of 2 mm and a height of 10.6 mm. The fourth sound absorption channel 4 has a channel length of 18 mm and a height of 43 mm. The connecting body 20 between the fourth sound absorption channel 4 and the fifth sound absorption channel 5 has a length of 2 mm and a height of 18 mm. The fifth sound absorption channel 5 has a channel length of 28 mm and a height of 43 mm.

[0054] The seventh coiled channel 16, the first sound absorption channel 1 has a channel length of 3.6 mm and a height of 28 mm. The connecting body 20 between the first sound absorption channel 1 and the second sound absorption channel 2 has a length of 2 mm and a height of 3.6 mm; the second sound absorption channel 2 has a channel length of 6 mm and a height of 28 mm. The connecting body 20 between the second sound absorption channel 2 and the third sound absorption channel 3 has a length of 2 mm and a height of 6 mm; the third sound absorption channel 3 has a channel length of 8.7 mm and a height of 28 mm. The connecting body 20 between the third sound absorption channel 3 and the fourth sound absorption channel 4 has a length of 2 mm and a height of 8.7 mm; the fourth sound absorption channel 4 has a channel length of 11.5 mm and a height of 28 mm. The connecting body 20 between the fourth sound absorption channel 4 and the fifth sound absorption channel 5 has a length of 2 mm and a height of 11.5 mm; the fifth sound absorption channel 5 has a channel length of 13.8 mm and a height of 28 mm. The connecting body 20 between the fifth sound absorption channel 5 and the sixth sound absorption channel 6 has a length of 2 mm and a height of 13.8 mm; the sixth sound absorption channel 6 has a channel length of 16.6 mm and a height of 28 mm. The connecting body 20 between the sixth sound absorption channel 6 and the seventh sound absorption channel 7 has a length of 2 mm and a height of 16.6 mm; the seventh sound absorption channel 7 has a channel length of 19 mm and a height of 28 mm. The connecting body 20 between the seventh sound absorption channel 7 and the eighth sound absorption channel 8 has a length of 2 mm and a height of 19 mm; the eighth sound absorption channel 8 has a channel length of 24.5 mm and a height of 28 mm. The connecting body 20 between the eighth sound absorption channel 8 and the ninth sound absorption channel 9 has a length of 2 mm and a height of 24.5 mm; the ninth sound absorption channel 9 has a channel length of 30 mm and a height of 28 mm.

[0055] The eighth coiled channel 17, the first sound absorption channel 1 has a channel length of 3.6 mm and a height of 44 mm. The connecting body 20 between the first sound absorption channel 1 and the second sound absorption channel 2 has a length of 2 mm and a height of 3.6 mm; the second sound absorption channel 2 has a channel length of 7.8 mm and a height of 44 mm. The connecting body 20 between the second sound absorption channel 2 and the third sound absorption channel 3 has a length of 2 mm and a height of 7.8 mm; the third sound absorption channel 3 has a channel length of 10.6 mm and a height of 44 mm. The connecting body 20 between the third sound absorption channel 3 and the fourth sound absorption channel 4 has a length of 2 mm and a height of 10.6 mm; the fourth sound absorption channel 4 has a channel length of 18 mm and a height of 44 mm. The connecting body 20 between the fourth sound absorption channel 4 and the fifth sound absorption channel 5 has a length of 2 mm and a height of 18 mm; the fifth sound absorption channel 5 has a channel length of 28 mm and a height of 44 mm.

[0056] Perform a finite element simulation analysis on the sound absorption characteristics of the above-mentioned folding coiled channel acoustic muffler. From Figure 7It can be seen that, while maintaining perfect ventilation, the overall sound absorption performance of a folded and coiled channel acoustic muffler structure is relatively good. In the figure, unit a is the first coiled channel, unit b is the second coiled channel, unit c is the third coiled channel, unit d is the fourth coiled channel, unit e is the fifth coiled channel, unit f is the sixth coiled channel, unit g is the seventh coiled channel, and unit i is the eighth coiled channel; at 196 Hz, sound absorption is mainly completed at the first coiled channel 10; at 200 Hz, sound absorption is mainly completed at the third coiled channel 12; at 204 Hz, sound absorption is mainly completed at the seventh coiled channel 16; at 207 Hz, sound absorption is mainly completed at the second coiled channel 11; at 210 Hz, sound absorption is mainly completed at the fifth coiled channel 14; at 212 Hz, sound absorption is mainly completed at the fourth coiled channel 13; at 216 Hz, sound absorption is mainly completed at the eighth coiled channel 17; at 221 Hz, sound absorption is mainly completed at the sixth coiled channel 15; as Figure 8 shown, in the range of 189 Hz - 225 Hz, the overall muffler achieved a sound absorption coefficient above 0.5, with a maximum sound absorption coefficient of 0.9, realizing low-frequency broadband sound absorption.

[0057] For the above sound absorption coefficient, its reflection coefficient can be obtained by calculating the impedance, and then calculated based on the reflection coefficient. The specific calculation formula is as follows:

[0058]

[0059]

[0060] A = 1 - |r| 2 (4)

[0061] In the formula: Z - impedance; k c - wave number of sound; x - width of the channel opening 19; E - structure width; L - length of the coiled channel; r is the reflection coefficient; A is the sound absorption coefficient.

[0062] The specific working principle of the folded and coiled channel acoustic muffler described in the present invention is explained as follows: When sound waves propagate along the axial direction of the muffler, sound waves of different frequencies will enter the coiled channels through different openings, and the thermo-viscous loss effect is realized by using the pressure difference between the outside and the internal channels to complete sound absorption; at the same time, there will be heat loss during the compression and expansion of the medium, which will increase the sound energy loss.

[0063] It should be specifically noted that there is a main coiled channel for completing sound absorption at each frequency, and other coiled channels assist in sound absorption, but the sound absorption effect is weak compared to the main channel, playing a weak coupling role, so it is not described in detail.

[0064] There are no specific requirements for the materials used in the structure of this application, and any rigid material can be used to achieve ideal results.

[0065] Summarizing the above embodiments, the foldable and coiled channel acoustic muffler described in the present invention can achieve an absorption coefficient of more than 0.5 in the range of 189 Hz - 225 Hz, and the highest absorption coefficient can reach 0.9, realizing low-frequency broadband sound absorption; the foldable and coiled channel acoustic muffler described in the present invention has a simple structure and is easy to adjust. Its shape can be changed by folding, and the sound absorption bandwidth can be broadened by adding more coiled channels later. It is widely used in industrial production; the foldable and coiled channel acoustic muffler described in the present invention has no specific requirements for the material, and only a solid rigid structure can achieve the effect.

[0066] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the invention. It can also be a reasonable combination of the features described in the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A foldable and coiled channel acoustic silencer, characterized in that: It includes a number of sound-absorbing units arranged in a matrix; each sound-absorbing unit is formed by the cooperation of a first coiled channel and a second coiled channel. A number of sound-absorbing channels are provided in both the first coiled channel and the second coiled channel, and the number of sound-absorbing channels are connected in a serpentine shape front and back. By setting a number of sound-absorbing channels, the transmission path of sound waves is extended to achieve the low-frequency sound-absorbing effect; The overall channel length of the first coiled channel and the second coiled channel is calculated based on the frequency corresponding to the target resonance peak, and the calculation formula is where f m - the frequency corresponding to the resonance peak, m - the mode, c - the speed of sound, L - the length of the coiled channel; The heights between a number of first coiled channels are all different, and the heights between a number of second coiled channels are also all different; The lengths of a number of sound-absorbing channels provided inside the same first coiled channel or the same second coiled channel increase in sequence, while the width and height remain unchanged; A number of connectors (20) are also provided in the first coiled channel and the second coiled channel. Different sound-absorbing channels within the same coiled channel are connected by the connectors (20); the height of a number of connectors (20) provided within the same coiled channel is the same as the length of the previous section of the sound-absorbing channel to which it is connected, and the width and length of the connectors (20) remain unchanged.

2. The foldable and coiled channel acoustic silencer according to claim 1, characterized in that: The first coiled channel includes a first coiled channel (10), a third coiled channel (12), a fifth coiled channel (14), and a seventh coiled channel (16). The first coiled channel (10), the third coiled channel (12), the fifth coiled channel (14), and the seventh coiled channel (16) are arranged in sequence from top to bottom and from left to right.

3. The foldable and coiled channel acoustic silencer according to claim 2, characterized in that: The second coiled channel includes a second coiled channel (11), a fourth coiled channel (13), a sixth coiled channel (15), and an eighth coiled channel (17). The second coiled channel (11) is arranged at the center of the first coiled channel (10), the fourth coiled channel (13) is arranged at the center of the third coiled channel (12), the sixth coiled channel (15) is arranged at the center of the fifth coiled channel (14), and the eighth coiled channel (17) is arranged at the center of the seventh coiled channel (16).

4. The foldable and coiled channel acoustic silencer according to claim 1 or 3, characterized in that: The folded coiled channel acoustic muffler further includes a partition (18), and the partition (18) wraps a number of first coiled channels and a number of second coiled channels inside.

5. The foldable and coiled channel acoustic silencer according to claim 4, characterized in that: The thickness of the partition (18) is 2 mm.

6. The foldable and coiled channel acoustic silencer according to claim 5, characterized in that: A channel opening (19) is provided on each first coiled channel and each second coiled channel.

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