A spiral channel micro-perforation sound absorption device

Abstract

The present invention provides a spiral channel micro-perforated sound absorption device, comprising an outer shell, an outer spiral structure, an inner spiral structure and a micro-perforated plate, wherein the outer spiral structure comprises an outer ring side wall and four spiral outer ring channels, each spiral outer ring channel is spirally arranged between the outer shell and the outer ring side wall, and each spiral outer ring channel is provided with an outer ring channel baffle at the lower end; the inner spiral structure comprises an inner ring cylinder and two spiral inner ring channels, each spiral inner ring channel is spirally arranged between the inner ring cylinder and the outer ring side wall, and each spiral inner ring channel is provided with an inner ring channel baffle at the lower end; the micro-perforated plate is provided with four outer ring perforated portions and two inner ring perforated portions, each outer ring perforated portion corresponds to the upper end opening of each spiral outer ring channel, and each inner ring perforated portion corresponds to the upper end opening of each spiral inner ring channel. The spiral channel micro-perforated sound absorption device provided by the present invention occupies a small space, is light in weight, and has a good absorption effect of wide-band low-frequency noise.

Description

Technical Field

[0001] The invention relates to the technical field of low-frequency sound absorption, and in particular to a spiral channel micro-perforation sound absorption device. Background Art

[0002] Low-frequency noise (<500Hz) exists in aerospace, high-speed trains and all areas of life. Long-term exposure to low-frequency noise can cause significant harm to the human body and even threaten people's lives. Low-frequency noise can also cause precision instruments to malfunction. Therefore, it is necessary to control low-frequency noise.

[0003] Noise control is mainly divided into two methods, active noise control and passive noise control. Active noise control technology cancels out noise by generating sound waves that are exactly the same as the noise spectrum and have completely opposite phases. Passive noise control technology usually uses sound-absorbing materials to achieve noise control, which has a large noise reduction space and good suppression effect on medium and high frequency noise. However, for low-frequency noise, passive noise control methods usually make the thickness of the sound-absorbing material equivalent to the working wavelength, occupy a large space, and the scope of engineering application is severely limited. Traditional resonant sound-absorbing structures are often used for low-frequency noise absorption, but the sound absorption band brought by the single sound absorption peak is too narrow, which makes it impossible to maintain efficient sound absorption in a wider frequency band, and the working frequency band is fixed, which makes it difficult to deal with irregular and disordered noise with irregular frequency changes. Therefore, it has become an urgent need in this field to design a frequency-adjustable sound-absorbing structure that can take into account the needs of low-frequency broadband noise absorption and structural lightweight. Summary of the invention

[0004] The purpose of the present invention is to provide a spiral channel micro-perforated sound absorption device, which can effectively solve the problem that the existing sound absorption structure is difficult to absorb broadband low-frequency noise, occupies a small space, is light in weight, and has good low-frequency sound absorption effect.

[0005] The present invention provides a spiral channel micro-perforation sound absorption device, comprising:

[0006] The outer shell is a cylindrical outer shell which is arranged vertically and has openings at both ends;

[0007] An outer spiral structure is arranged inside the outer shell, and the outer spiral structure includes an outer ring side wall and four spiral outer ring channels, the outer ring side wall is a cylindrical tube with openings at both ends, and each of the spiral outer ring channels is respectively arranged in a spiral shape between the outer shell and the outer ring side wall; an outer ring channel baffle is arranged at the lower end of each of the spiral outer ring channels, and the setting height of each of the outer ring channel baffles is different;

[0008] An inner spiral structure is arranged inside the outer ring side wall, the inner spiral structure comprises an inner ring cylinder and two spiral inner ring channels, each of the spiral inner ring channels is arranged in a spiral shape between the inner ring cylinder and the outer ring side wall; an inner ring channel baffle is arranged at a lower end of each of the spiral inner ring channels, and each of the inner ring channel baffles is arranged at a different height;

[0009] A micro-perforated plate is arranged at the upper end of the outer shell, and is provided with four outer ring perforated portions and two inner ring perforated portions. Each of the outer ring perforated portions corresponds one-to-one to the upper end opening of each of the spiral outer ring channels, and each of the inner ring perforated portions corresponds one-to-one to the upper end opening of each of the spiral inner ring channels.

[0010] According to a spiral channel micro-perforation sound absorption device provided by the present invention, the inner circle cylinder, the outer circle side wall and the outer shell are coaxially arranged, and the inner circle cylinder, the outer circle side wall and the outer shell have the same height.

[0011] According to a spiral channel micro-perforation sound absorption device provided by the present invention, an outer ring chamber is formed between the outer shell and the outer ring side wall, and the upper end openings of each spiral outer ring channel are evenly arranged at the upper end of the outer ring chamber.

[0012] According to a spiral channel micro-perforated sound absorption device provided by the present invention, an inner circle chamber is formed between the inner circle cylinder and the outer circle side wall, and the upper end openings of each of the spiral inner circle channels are evenly arranged at the upper end of the inner circle chamber.

[0013] According to a spiral channel micro-perforation sound absorption device provided by the present invention, the upper end opening of each spiral outer ring channel is fan-shaped, and the outer ring perforated portion is a fan-shaped portion that matches the upper end opening of the spiral outer ring channel; the upper end opening of each spiral inner ring channel is fan-shaped, and the inner ring perforated portion is a fan-shaped portion that matches the upper end opening of the spiral inner ring channel.

[0014] According to a spiral channel micro-perforation sound absorption device provided by the present invention, the setting position of each outer ring channel baffle is successively increased in the clockwise direction; the setting position of each inner ring channel baffle is successively increased in the clockwise direction, and the setting position of the inner ring channel baffle is higher than the setting position of the outer ring channel baffle.

[0015] According to a spiral channel micro-perforation sound absorption device provided by the present invention, the four spiral outer ring channels are respectively a first spiral outer ring channel, a second spiral outer ring channel, a third spiral outer ring channel and a fourth spiral outer ring channel; a first outer ring spiral blade, a second outer ring spiral blade, a third outer ring spiral blade and a fourth outer ring spiral blade are respectively arranged between the outer shell and the outer ring side wall, the first spiral outer ring channel is formed between the first outer ring spiral blade and the second outer ring spiral blade, the second spiral outer ring channel is formed between the second outer ring spiral blade and the third outer ring spiral blade, the third spiral outer ring channel is formed between the third outer ring spiral blade and the fourth outer ring spiral blade, and the fourth spiral outer ring channel is formed between the fourth outer ring spiral blade and the first outer ring spiral blade.

[0016] According to a spiral channel micro-perforation sound absorption device provided by the present invention, two outer ring vertical baffles are respectively provided at the upper end of each spiral outer ring channel, and each outer ring vertical baffle is installed between the outer shell and the outer ring side wall to form an upper end opening of the spiral outer ring channel between the two outer ring vertical baffles.

[0017] According to a spiral channel micro-perforation sound absorption device provided by the present invention, the two spiral inner ring channels are respectively a first spiral inner ring channel and a second spiral inner ring channel; two inner ring spiral blades are provided between the inner ring cylinder and the outer ring side wall, and the two inner ring spiral blades divide the inner ring chamber into the first spiral inner ring channel and the second spiral inner ring channel.

[0018] According to a spiral channel micro-perforation sound absorption device provided by the present invention, two inner circle vertical baffles are respectively provided at the upper end of each spiral inner circle channel, and each inner circle vertical baffle is installed between the inner circle cylinder and the outer circle side wall to form an upper end opening of the spiral inner circle channel between the two inner circle vertical baffles.

[0019] The spiral channel micro-perforated sound absorption device provided by the invention arranges the outer spiral structure inside the outer shell, arranges the inner spiral structure inside the outer ring side wall, arranges the micro-perforated plate at the upper end of the outer shell, arranges four spiral outer ring channels between the outer shell and the outer ring side wall, arranges outer ring channel baffles at the lower end of each spiral outer ring channel, so that the setting heights of the baffles of each outer ring channel are different, arranges two spiral inner ring channels between the inner ring cylinder and the outer ring side wall, arranges inner ring channel baffles at the lower end of each spiral inner ring channel, so that the setting heights of the baffles of each inner ring channel are different, and arranges four outer ring perforated portions corresponding to the upper end openings of each spiral outer ring channel and corresponding to the upper end openings of each spiral inner ring channel on the micro-perforated plate. The upper end openings of the channels correspond to two inner circle perforations one by one, thereby forming six sound absorbing units. Since the setting heights of the outer circle channel baffles and the inner circle channel baffles are different, the lengths of the spiral outer circle channels and the lengths of the spiral inner circle channels are different, so that each sound absorbing unit has a different acoustic path, that is, each sound absorbing unit has a different working frequency. When the sound wave frequency enters the working frequency band of each sound absorbing unit, impedance matching is generated, so that when the sound wave enters the sound absorbing unit, it can violently rub against the microporous wall surfaces of the outer circle perforations and the inner circle perforations to dissipate the sound energy. Since the working frequencies of each sound absorbing unit are close to each other, the sound absorbing device has a wider high-efficiency low-frequency sound absorption frequency band. Therefore, the spiral channel micro-perforated sound absorption device provided by the invention combines the advantages of the spiral channel and the micro-perforated sound absorption structure in thickness and wide-band efficient sound absorption, respectively, and achieves a low-frequency and efficient sound absorption effect at a sub-wavelength structure thickness. It can effectively solve the problem that 200-500Hz noise is difficult to absorb at a sub-wavelength thickness, occupies less space, is lighter in weight, and has a better wide-band low-frequency sound absorption effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 is a schematic structural diagram of a spiral channel micro-perforated sound absorbing device according to an embodiment of the present invention;

[0022] Figure 2 2 is a schematic structural diagram of an outer spiral structure in a spiral channel micro-perforated sound absorbing device according to an embodiment of the present invention;

[0023] Figure 3 1 is a schematic structural diagram of an inner spiral structure in a spiral channel micro-perforated sound absorbing device according to an embodiment of the present invention;

[0024] Figure 4 1 is a schematic diagram of the structure of a micro-perforated plate in a spiral channel micro-perforated sound absorbing device according to an embodiment of the present invention;

[0025] Figure 5 2 is a schematic diagram of the structure of the outer shell of the spiral channel micro-perforated sound absorbing device according to an embodiment of the present invention;

[0026] Figure 6 1 is a schematic structural diagram of a first sound absorbing unit in a spiral channel micro-perforated sound absorbing device according to an embodiment of the present invention;

[0027] Figure 7 1 is a schematic structural diagram of six sound absorbing units in a spiral channel micro-perforated sound absorbing device according to an embodiment of the present invention;

[0028] Figure 8 1 is a graph of the sound absorption coefficient of the spiral channel micro-perforated sound absorption device in the frequency range of 200 to 500 Hz according to an embodiment of the present invention;

[0029] Fig. 9 It is a sound absorption coefficient diagram of the spiral channel micro-perforated sound absorption device in the frequency range of 400 to 1000 Hz after frequency modulation according to an embodiment of the present invention.

[0030] Description of reference numerals:

[0031] 1: Shell;

[0032] 2: outer spiral structure; 21: first spiral outer ring channel; 22: second spiral outer ring channel; 23: third spiral outer ring channel; 24: fourth spiral outer ring channel; 25: first outer ring channel baffle; 26: second outer ring channel baffle; 27: third outer ring channel baffle; 28: fourth outer ring channel baffle; 29: outer ring side wall;

[0033] 3: inner spiral structure; 31: first spiral inner circle channel; 32: second spiral inner circle channel; 33: first inner circle channel baffle; 34: second inner circle channel baffle; 35: inner circle cylinder;

[0034] 4: micro-perforated plate; 41: first outer ring perforated portion; 42: second outer ring perforated portion; 43: third outer ring perforated portion; 44: fourth outer ring perforated portion;

[0035] 61: first sound absorbing unit; 62: second sound absorbing unit; 63: third sound absorbing unit; 64: fourth sound absorbing unit; 65: fifth sound absorbing unit; 66: sixth sound absorbing unit. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0038] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] like Figure 1 system Figure 7 As shown, the spiral channel micro-perforated sound absorbing device of the embodiment of the present invention comprises a shell 1, an outer spiral structure 2, an inner spiral structure 3 and a micro-perforated plate 4, wherein the shell 1 is a cylindrical shell arranged vertically and opened at both ends. The shell 1, the outer spiral structure 2 and the inner spiral structure 3 are arranged from the outside to the inside.

[0040] The outer spiral structure 2 includes an outer ring side wall 29 and four spiral outer ring channels. The outer ring side wall 29 is arranged inside the outer shell 1. The outer ring side wall 29 is a cylindrical tube with openings at both ends. Each spiral outer ring channel is spirally arranged between the outer shell 1 and the outer ring side wall 29. An outer ring channel baffle is provided at the lower end of each spiral outer ring channel, and the setting height of each outer ring channel baffle is different, that is, the length of each spiral outer ring channel is different.

[0041] The inner spiral structure 3 includes an inner circle cylinder 35 and two spiral inner circle channels, wherein the inner circle cylinder 35 is arranged inside the outer circle side wall 29, and each spiral inner circle channel is arranged in a spiral shape between the inner circle cylinder 35 and the outer circle side wall 29. An inner circle channel baffle is arranged at the lower end of each spiral inner circle channel, and each inner circle channel baffle is arranged at a different height, that is, each spiral inner circle channel has a different length.

[0042] Among them, the micro-perforated plate 4 is arranged at the upper end of the outer shell 1, and is provided with four outer ring perforations and two inner ring perforations. Each outer ring perforation portion corresponds one-to-one to the upper end opening of each spiral outer ring channel, and each inner ring perforation portion corresponds one-to-one to the upper end opening of each spiral inner ring channel.

[0043] The spiral channel micro-perforated sound absorbing device of the embodiment of the present invention is provided with four spiral outer ring channels between the outer ring side wall 29, and outer ring channel baffles are respectively provided at the lower end of each spiral outer ring channel, so that the setting heights of each outer ring channel baffle are different; two spiral inner ring channels are provided between the inner ring cylinder 35 and the outer ring side wall 29, and inner ring channel baffles are respectively provided at the lower end of each spiral inner ring channel, so that the setting heights of each inner ring channel baffle are different; four outer ring perforated portions corresponding to the upper end openings of each spiral outer ring channel and two inner ring perforated portions corresponding to the upper end openings of each spiral inner ring channel are provided on the micro-perforated plate 4, so that six sound absorbing units are formed; since the setting heights of each outer ring channel baffle and each inner ring channel baffle are different, the lengths of each spiral outer ring channel and the lengths of each spiral inner ring channel are different, so that each sound absorbing unit has a different acoustic path, that is, each sound absorbing unit has a different operating frequency. When the sound wave frequency enters the working frequency band of each sound absorbing unit, impedance matching occurs, so that when the sound wave enters the sound absorbing unit, it can violently rub against the microporous wall surfaces of each outer ring perforation part and each inner ring perforation part to dissipate the sound energy. Since the working frequencies of each sound absorbing unit are close to each other, the sound absorbing device has a wider, efficient, low-frequency sound absorption band.

[0044] Therefore, the spiral channel micro-perforated sound absorption device of the embodiment of the present invention combines the advantages of the spiral channel and the micro-perforated sound absorption structure in thickness and broadband efficient sound absorption, respectively, and realizes the low-frequency efficient sound absorption effect at the sub-wavelength structure thickness, which can effectively solve the problem that 200-500Hz noise is difficult to absorb at the sub-wavelength thickness, occupies less space, is lighter in weight, and has better broadband low-frequency sound absorption effect. Therefore, it has good application prospects in high-speed trains, aerospace and other equipment fields that require low-frequency noise suppression and lightweight.

[0045] In some embodiments of the present invention, the inner circle cylinder 35, the outer circle side wall 29 and the outer shell 1 are coaxially arranged, and the inner circle cylinder 35, the outer circle side wall 29 and the outer shell 1 have the same height.

[0046] Specifically, an outer ring chamber is formed between the outer shell 1 and the outer ring side wall 29, and the upper end openings of each spiral outer ring channel are evenly arranged at the upper end of the outer ring chamber. An inner ring chamber is formed between the inner ring cylinder 35 and the outer ring side wall 29, and the upper end openings of each spiral inner ring channel are evenly arranged at the upper end of the inner ring chamber.

[0047] In some embodiments of the present invention, the setting position of each outer ring channel baffle can be raised in sequence in the clockwise direction, and the setting position of each inner ring channel baffle can be raised in sequence in the clockwise direction, and the setting position of the inner ring channel baffle can be made higher than the setting position of the outer ring channel baffle, so that the setting positions of each outer ring channel baffle and each inner ring channel baffle in the height direction are different.

[0048] Of course, the position of each outer ring channel baffle can be adjusted along the extension direction of each spiral outer ring channel, and the position of each inner ring channel baffle can be adjusted along the extension direction of each spiral inner ring channel, so as to form spiral channels with acoustic paths of different lengths. That is, the length of each spiral outer ring channel is adjusted by adjusting the position of each outer ring channel baffle, and the length of each spiral inner ring channel is adjusted by adjusting the position of each inner ring channel baffle, so as to achieve absorption of different sound absorption frequency bands.

[0049] In some embodiments of the present invention, the four spiral outer ring channels are respectively the first spiral outer ring channel 21, the second spiral outer ring channel 22, the third spiral outer ring channel 23 and the fourth spiral outer ring channel 24. Four outer ring spiral blades are respectively arranged between the housing 1 and the outer ring side wall 29, that is, the four outer ring spiral blades can separate the outer ring chamber into four spiral outer ring channels. Among them, the four outer ring spiral blades are respectively the first outer ring spiral blade, the second outer ring spiral blade, the third outer ring spiral blade and the fourth outer ring spiral blade, the first spiral outer ring channel 21 is formed between the first outer ring spiral blade and the second outer ring spiral blade, the second spiral outer ring channel 22 is formed between the second outer ring spiral blade and the third outer ring spiral blade, the third spiral outer ring channel 23 is formed between the third outer ring spiral blade and the fourth outer ring spiral blade, and the fourth spiral outer ring channel 24 is formed between the fourth outer ring spiral blade and the first outer ring spiral blade.

[0050] Further, the outer ring channel baffles are: a first outer ring channel baffle 25 arranged at the lower end of the first spiral outer ring channel 21, a second outer ring channel baffle 26 arranged at the lower end of the second spiral outer ring channel 22, a third outer ring channel baffle 27 arranged at the lower end of the third spiral outer ring channel 23, and a fourth outer ring channel baffle 28 arranged at the lower end of the fourth spiral outer ring channel 24.

[0051] Further, the four outer ring perforations on the micro-perforated plate 4 are respectively: a first outer ring perforation portion 41 corresponding to the upper end opening of the first spiral outer ring channel 21, a second outer ring perforation portion 42 corresponding to the upper end opening of the second spiral outer ring channel 22, a third outer ring perforation portion 43 corresponding to the upper end opening of the third spiral outer ring channel 23, and a fourth outer ring perforation portion 44 corresponding to the upper end opening of the fourth spiral outer ring channel 24.

[0052] Further, two outer ring vertical baffles are respectively provided at the first end of each spiral outer ring channel, and each outer ring vertical baffle is installed between the housing 1 and the outer ring side wall 29, so that the upper end opening of the spiral outer ring channel is formed between the two outer ring vertical baffles. The upper end opening of each spiral outer ring channel is fan-shaped, and each outer ring perforated portion is fan-shaped to match the upper end opening of the spiral outer ring channel.

[0053] In some embodiments of the present invention, the two spiral inner ring channels are respectively a first spiral inner ring channel 31 and a second spiral inner ring channel 32. Two inner ring spiral blades are respectively arranged between the inner ring cylinder 35 and the outer ring side wall 29, and the two inner ring spiral blades can separate the inner ring chamber into the first spiral inner ring channel 31 and the second spiral inner ring channel 32.

[0054] Specifically, each inner circle channel baffle is respectively: a first inner circle channel baffle 33 arranged at the lower end of the first spiral inner circle channel 31 and a second inner circle channel baffle 34 arranged at the lower end of the second spiral inner circle channel 32 .

[0055] Further, the two inner ring perforations on the micro-perforated plate 4 are respectively: a first inner ring perforation 45 corresponding to the upper end opening of the first spiral inner ring channel 31 and a second inner ring perforation 46 corresponding to the upper end opening of the second spiral inner ring channel 32. The upper end opening of each spiral inner ring channel is fan-shaped, and each inner ring perforation is fan-shaped to match the upper end opening of the spiral inner ring channel.

[0056] Furthermore, two inner circle vertical baffles are respectively provided at the upper end of each spiral inner circle channel, and each inner circle vertical baffle is installed between the inner circle cylinder 35 and the outer circle side wall 29 to form an upper end opening of the spiral inner circle channel between the two inner circle vertical baffles.

[0057] Thus, the six sound absorbing units are respectively a first sound absorbing unit 61, a second sound absorbing unit 62, a third sound absorbing unit 63, a fourth sound absorbing unit 64, a fifth sound absorbing unit 65 and a sixth sound absorbing unit 66, wherein the first sound absorbing unit 61 comprises a first outer ring perforated portion 41, a first spiral outer ring channel 21 and a first outer ring channel baffle 25, the second sound absorbing unit 62 comprises a second outer ring perforated portion 42, a second spiral outer ring channel 22 and a second outer ring channel baffle 26, and the third sound absorbing unit 6 3 includes a third outer ring perforated portion 43, a third spiral outer ring channel 23 and a third outer ring channel baffle 27, a fourth sound absorbing unit 64 includes a fourth outer ring perforated portion 44, a fourth spiral outer ring channel 24 and a fourth outer ring channel baffle 28, a fifth sound absorbing unit 65 includes a first inner ring perforated portion 45, a first spiral inner ring channel 31 and a first inner ring channel baffle 33, and a sixth sound absorbing unit 66 includes a second inner ring perforated portion 46, a second spiral inner ring channel 32 and a second inner ring channel baffle 34.

[0058] In a specific embodiment, the first outer ring channel baffle 25, the second outer ring channel baffle 26, the third outer ring channel baffle 27, the fourth outer ring channel baffle 28, the first inner ring channel baffle 33 and the second inner ring channel baffle 34 can be arranged in order to increase their positions. That is, the lengths of the first spiral outer ring channel 21, the second spiral outer ring channel 22, the third spiral outer ring channel 23, the fourth spiral outer ring channel 24, the first spiral inner ring channel 31 and the second spiral inner ring channel 32 are reduced in order, thereby gradually reducing the acoustic paths of the first sound absorbing unit 61, the second sound absorbing unit 62, the third sound absorbing unit 63, the fourth sound absorbing unit 64, the fifth sound absorbing unit 65 and the sixth sound absorbing unit 66.

[0059] The spiral channel micro-perforated sound absorbing device of the embodiment of the present invention, through the arrangement of each spiral outer ring channel and each spiral inner ring channel, enables the sound absorbing device to obtain a longer propagation path in the direction of sound wave incidence, thereby obtaining a lower frequency resonance frequency. At the same time, due to the arrangement of each outer ring channel baffle and each inner ring channel baffle, the sound absorbing device forms six radially arranged different sound absorbing units, each of which has a different equivalent depth, and multiple sound absorbing units with different resonance frequencies are arranged in parallel, which effectively improves the effect of the sound absorbing device in absorbing wide-band low-frequency noise, and enables the sound absorbing device to have the advantages of light weight, small space occupation, strong low-frequency sound absorption performance, and wide sound absorption bandwidth.

[0060] In some embodiments of the present invention, the design formula of the spiral surface of each spiral outer ring channel and each spiral inner ring channel is as follows:

[0061]

[0062] Among them, s1 and s2 are two independent variables, and their value ranges are [r2, r1] and [0, 2π] respectively; r1 and r2 are the outer diameter and inner diameter of the spiral surface respectively; l = r1-r2 is the width of the spiral surface; n is the number of turns of the spiral surface; h is the normal height of the spiral surface; t is the thickness of the spiral blade; L = h+t is the pitch of the spiral surface.

[0063] By increasing the thickness h of the spiral surface along the z-axis direction, a spiral channel can be obtained. The spiral channel can be equivalent to a straight channel with the same cross-sectional area and an equivalent length of D. Obviously, the equivalent length of the spiral channel is positively correlated with the number of spiral turns.

[0064] In a specific embodiment, the number of spiral turns of the first sound absorbing unit 61, the second sound absorbing unit 62, the third sound absorbing unit 63, the fourth sound absorbing unit 64, the fifth sound absorbing unit 65 and the sixth sound absorbing unit 66 decreases in sequence, and the sound absorption coefficient α of each sound absorbing unit is n The calculation formula is as follows:

[0065]

[0066] Where r is the relative acoustic resistivity; m is the relative acoustic mass; ω = 2πf is the angular frequency, f is the frequency of the sound wave; c is the speed of sound in air; D n is the equivalent length of each sound absorbing unit.

[0067] Among them, by keeping the perforation parameters of the sound absorbing unit the same and changing the equivalent length corresponding to the sound absorbing unit alone, the resonance frequency of the sound absorbing unit can be directly changed. Since the sound absorbing unit curls the channel of the sound wave into a spiral channel, the equivalent length of the sound absorbing unit is greatly increased at the same thickness.

[0068] In a specific embodiment, the outer ring perforations and inner ring perforations on the micro-perforated plate 4 have equal areas, equal perforation rates, equal perforation diameters, and only the corresponding equivalent lengths of the sound absorbing units are different. The larger the equivalent length, the lower the frequency. Therefore, the first sound absorbing unit 61, the second sound absorbing unit 62, the third sound absorbing unit 63, the fourth sound absorbing unit 64, the fifth sound absorbing unit 65, and the sixth sound absorbing unit 66 have sound absorption resonance frequencies from low to high in sequence. When the frequency of the incident sound wave is between the two resonance frequencies, the two sound absorbing units will have strong coupling, and the sound absorption coefficient is only slightly lower than the resonance frequency, thereby obtaining a continuous low-frequency broadband sound absorption effect, thereby overcoming the problems of poor low-frequency sound absorption effect and narrow sound absorption frequency band of the traditional sound absorption structure.

[0069] In this embodiment, the sound wave incident areas corresponding to the six sound absorbing units are the same, but the spiral channels of the spiral channels of each sound absorbing unit are different, such as Figure 8 As shown, the six sound absorbing units have excellent sound absorbing effect in the frequency band of 200 to 500 Hz.

[0070] In this embodiment, by changing the positions of the outer circle channel baffles and the inner circle channel baffles, the frequency modulation of the sound absorbing device can be achieved, such as Fig. 9 As shown, after frequency modulation, the six sound absorbing units have excellent sound absorbing effect in the frequency band of 400 to 900 Hz.

[0071] Furthermore, in another specific embodiment, the parameters of the perforated portion of each sound absorbing unit may be different, that is, the parameters of the outer ring perforated portions and the inner ring perforated portions on the micro-perforated plate may be different, thereby obtaining a larger variation space of the sound absorption coefficient.

[0072] It can be seen from this that the working principle of the spiral channel micro-perforated sound absorption device of the embodiment of the present invention is as follows:

[0073] The sound absorbing device is provided with six sound absorbing units with spiral channels, so that the propagation path of the sound wave in the sound absorbing unit becomes longer, the resonance frequency of the sound absorbing unit is reduced, and when the frequency of the incident sound wave is low, the acoustic capacitance is larger than that of the traditional micro-perforated sound absorbing structure, and can resonate with it to absorb sound. At the same time, since the structural parameters of each sound absorbing unit are adjustable, sub-wavelength thickness sound absorption in the direction of the incident sound wave can be achieved, making full use of the limited space and overcoming the problem that the traditional sound absorbing structure occupies a large space and has poor low-frequency sound absorption effect.

[0074] The sound wave is vertically incident on the sound absorbing unit. When the sound wave frequency is consistent with the working frequency band of the sound absorbing unit, impedance matching is formed, and the cavity of the spiral channel of the sound absorbing unit resonates with the air in the micropores on the micro-perforated plate. During resonance, the instantaneous sound velocity in the micropores reaches the maximum, and the intense friction with the wall of the pores dissipates the sound energy, thereby efficiently absorbing the noise at the resonance frequency.

[0075] like Figure 8 As shown, when the six resonance frequencies formed by the six sound absorbing units increase successively, the peak value of the sound absorption coefficient of each sound absorbing unit is designed to be maintained above 0.95, ensuring that the sound absorption coefficient of the combination of the six sound absorbing units is maintained at a high level.

[0076] like Fig. 9 As shown, by adjusting the positions of the outer ring channel baffles and the inner ring channel baffles, the sound absorption frequency band of the sound absorption device can be adjusted. After the adjustment, the high-efficiency sound absorption coefficient of the sound absorption structure is transferred from the 200-500 Hz frequency band to the 400-900 Hz frequency band.

[0077] In summary, the spiral channel micro-perforated sound absorption device of the embodiment of the present invention can enable sound waves to obtain a longer propagation path at the same structural thickness, and the acoustic capacitance is larger than that of the traditional micro-perforated sound absorption structure at a lower frequency, and can complete resonance at a lower frequency to obtain a perfect sound absorption effect. At the same time, by combining multiple sound absorption units with spiral channels of different lengths, the sound absorption device can obtain multiple resonant frequencies, thereby having multiple sound absorption peaks. Therefore, the spiral channel micro-perforated sound absorption device of the embodiment of the present invention combines the advantages of the spiral channel and the micro-perforated sound absorption structure in thickness and broadband efficient sound absorption, respectively, and achieves a low-frequency and efficient sound absorption effect at a sub-wavelength structural thickness, which can effectively solve the problem that 200-500Hz noise is difficult to absorb at a sub-wavelength thickness, and can achieve absorption of different sound absorption frequency bands by adjusting the structural parameters of each sound absorption unit, thereby enabling the sound absorption device to have good application prospects in the field of equipment such as high-speed trains, aerospace, etc. that require low-frequency noise suppression and lightweight.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spiral channel micro-perforated sound absorption device, characterized in that: include: The outer shell is a cylindrical outer shell which is arranged vertically and has openings at both ends; An outer spiral structure is arranged inside the outer shell, and the outer spiral structure includes an outer ring side wall and four spiral outer ring channels, the outer ring side wall is a cylindrical tube with openings at both ends, and each of the spiral outer ring channels is respectively arranged in a spiral shape between the outer shell and the outer ring side wall; an outer ring channel baffle is arranged at the lower end of each of the spiral outer ring channels, and the setting height of each of the outer ring channel baffles is different; An inner spiral structure is arranged inside the outer ring side wall, the inner spiral structure comprises an inner ring cylinder and two spiral inner ring channels, each of the spiral inner ring channels is arranged in a spiral shape between the inner ring cylinder and the outer ring side wall; an inner ring channel baffle is arranged at a lower end of each of the spiral inner ring channels, and each of the inner ring channel baffles is arranged at a different height; A micro-perforated plate is arranged at the upper end of the shell, and is provided with four outer ring perforated portions and two inner ring perforated portions, each of the outer ring perforated portions corresponds to the upper end opening of each of the spiral outer ring channels, and each of the inner ring perforated portions corresponds to the upper end opening of each of the spiral inner ring channels; The inner cylinder, the outer side wall and the outer shell are coaxially arranged, and the inner cylinder, the outer side wall and the outer shell have the same height; An outer ring chamber is formed between the outer shell and the outer ring side wall, and the upper end openings of the spiral outer ring channels are evenly arranged at the upper ends of the outer ring chamber; The setting position of each outer ring channel baffle is successively increased in the clockwise direction; the setting position of each inner ring channel baffle is successively increased in the clockwise direction, and the setting position of the inner ring channel baffle is higher than the setting position of the outer ring channel baffle; The four spiral outer ring channels are respectively the first spiral outer ring channel, the second spiral outer ring channel, the third spiral outer ring channel and the fourth spiral outer ring channel; the first outer ring spiral blade, the second outer ring spiral blade, the third outer ring spiral blade and the fourth outer ring spiral blade are respectively arranged between the outer shell and the outer ring side wall, the first spiral outer ring channel is formed between the first outer ring spiral blade and the second outer ring spiral blade, the second spiral outer ring channel is formed between the second outer ring spiral blade and the third outer ring spiral blade, the third spiral outer ring channel is formed between the third outer ring spiral blade and the fourth outer ring spiral blade, and the fourth spiral outer ring channel is formed between the fourth outer ring spiral blade and the first outer ring spiral blade.

2. The spiral channel micro-perforated sound absorbing device according to claim 1 is characterized in that: An inner circle chamber is formed between the inner circle cylinder and the outer circle side wall, and the upper end openings of the spiral inner circle channels are evenly arranged at the upper ends of the inner circle chamber.

3. The spiral channel micro-perforated sound absorbing device according to claim 2 is characterized in that: The upper end opening of each spiral outer ring channel is fan-shaped, and the outer ring perforated portion is a fan-shaped portion that matches the upper end opening of the spiral outer ring channel; the upper end opening of each spiral inner ring channel is fan-shaped, and the inner ring perforated portion is a fan-shaped portion that matches the upper end opening of the spiral inner ring channel.

4. The spiral channel micro-perforated sound absorbing device according to claim 1, characterized in that: Two outer ring vertical baffles are respectively provided at the upper end of each of the spiral outer ring channels, and each of the outer ring vertical baffles is installed between the outer shell and the outer ring side wall to form an upper end opening of the spiral outer ring channel between the two outer ring vertical baffles.

5. The spiral channel micro-perforated sound absorbing device according to claim 2, characterized in that: The two spiral inner ring channels are respectively the first spiral inner ring channel and the second spiral inner ring channel; two inner ring spiral blades are arranged between the inner ring cylinder and the outer ring side wall, and the two inner ring spiral blades divide the inner ring chamber into the first spiral inner ring channel and the second spiral inner ring channel.

6. The spiral channel micro-perforated sound absorbing device according to claim 5, characterized in that: Two inner ring vertical baffles are respectively provided at the upper end of each of the spiral inner ring channels, and each of the inner ring vertical baffles is installed between the inner ring cylinder and the outer ring side wall to form an upper end opening of the spiral inner ring channel between the two inner ring vertical baffles.

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