An acoustic metamaterial silencer for high flow rate ducts

Abstract

The application provides an acoustic metamaterial muffler for a high-flow-rate pipeline, and relates to the technical field of acoustic metamaterial muffling devices. The acoustic metamaterial muffler for the high-flow-rate pipeline comprises a resonance unit, a reverse resonance channel, a first connecting unit, a second connecting unit, a first central channel, a first through pipe and an acoustic flow separation unit. In the process of sound transmission from the first connecting unit to the second connecting unit, the acoustic flow separation unit realizes acoustic-flow separation in the first through pipe in the first central channel, controls the flow of fluid in the resonance unit, avoids vortex flow caused by the impact of fluid on the entrances of the reverse resonance channels, and thereby suppresses secondary noise radiation. Meanwhile, in the resonance unit, wide-band noise reduction is realized in the reverse resonance channels, and additional mufflers are not needed to be connected in series in the axial direction, so that the actual space requirements in practical applications can be met, and different frequency noises can be attenuated.

Description

Technical Field

[0001] This invention relates to the field of acoustic metamaterial silencing equipment technology, and in particular to an acoustic metamaterial silencing device for high flow rate pipelines. Background Technology

[0002] In recent years, noise pollution has received increasing attention, but it remains a widespread problem, particularly in automotive pipelines, aircraft engines, and industrial parks. In some scenarios requiring duct ventilation, duct noise is especially prominent. Duct mufflers have important applications in the automotive, shipbuilding, aerospace, and industrial production sectors. Traditional mufflers can be categorized into resistive, reactive, and composite mufflers. However, they all suffer from the following main problems: First, mufflers have inherent operating frequency bands. When the noise frequency in the duct is low, traditional mufflers are limited by noise wavelength and mass laws, often performing better on high-frequency noise or requiring larger dimensions, thus limiting their practical application. Acoustic metamaterials, as a specific application of metamaterials in the acoustic field, are also known as acoustic metastructures or acoustic metamaterials. By adjusting the structural parameters of acoustic metamaterial units and arranging multiple units topologically, negative mass density, negative bulk modulus, negative Poisson's ratio, and near-zero refractive index, which are not found in natural materials, can be obtained, thereby achieving macroscopic control of noise at different frequencies. Currently, there is limited research on the application of acoustic metamaterials in pipes. However, based on existing research, replacing traditional acoustic materials with acoustic metamaterials can significantly improve the effective bandwidth, noise reduction, and low-frequency noise reduction effect of silencers.

[0003] However, existing acoustic metamaterial silencers have two drawbacks: First, when a flow field exists within the pipe, eddies are generated on the side branches of the silencer, and the shedding of these eddies generates secondary noise radiation, thus introducing new noise sources into the pipe. Second, the silencing effect and application range are limited to small-diameter pipes. To achieve broadband noise reduction, multiple silencers need to be connected in series axially, which makes it impossible to guarantee that their dimensions meet the actual space requirements in practical applications, thus failing to attenuate noise at different frequencies.

[0004] Therefore, the aforementioned technical issues still need to be addressed. Summary of the Invention

[0005] The purpose of this invention is to provide an acoustic metamaterial silencer for high-flow-rate pipelines, which controls the flow of fluid within the resonant unit, avoids eddies generated by the impact of fluid on the inlets of each reverse resonant channel, and thus suppresses secondary noise radiation. Simultaneously, it achieves broadband noise reduction, avoiding the need for multiple silencers connected in series axially, which would compromise the actual space requirements of the silencer's dimensions in practical applications, thereby achieving attenuation of noise at different frequencies.

[0006] To address the aforementioned technical problems, the embodiments of the present invention provide the following technical solutions:

[0007] The first aspect of this invention provides an acoustic metamaterial silencer for high-flow-rate pipelines, comprising:

[0008] Resonant unit;

[0009] Reverse resonant channels are respectively arranged in the resonant unit, and the channel paths between adjacent reverse resonant channels are opposite;

[0010] A first connecting unit is disposed on the upper part of the resonant unit and connected to the resonant unit;

[0011] The second connecting unit is disposed at the lower part of the resonant unit and is connected to the resonant unit;

[0012] The first central channel is formed by the resonant unit, the first connecting unit, and the second connecting unit;

[0013] The first conduit is disposed within the first central channel and connected to the first central channel;

[0014] The acoustic-to-fluid separation unit is connected to the first conduit and is located at the entrance of each of the reverse resonant channels.

[0015] Furthermore, the resonant unit includes:

[0016] The first resonant partition is connected to both the first connecting unit and the second connecting unit.

[0017] The second resonant partition is located inside the first resonant partition. The second resonant partition is connected to the first through pipe and is also connected to the first resonant partition in the opposite direction.

[0018] The third resonant partition is located inside the second resonant partition. The second resonant partition is connected to the first through pipe and simultaneously connected to the second resonant partition in the opposite direction.

[0019] The fourth resonant partition is located inside the third resonant partition. The second resonant partition is connected to the first through pipe and simultaneously connected to the third resonant partition in the opposite direction.

[0020] The fifth resonant partition is located inside the fourth resonant partition. The second resonant partition is connected to the first through pipe and simultaneously connected to the fourth resonant partition in the opposite direction.

[0021] Furthermore, the first resonant partition includes a first partition and a second partition connected to the first partition, and the end of the second partition near the first partition is connected to the end of the first partition near the second partition.

[0022] The second resonant partition includes a third partition and a fourth partition connected to both the third partition and the second partition, the third partition also being connected to the first through pipe;

[0023] The third resonant partition includes a fifth partition and a sixth partition connected to both the fifth partition and the third partition. The fifth partition is also connected to the first through pipe.

[0024] The fourth resonant partition includes a seventh partition and an eighth partition connected to both the seventh partition and the fifth partition. The seventh partition is also connected to the first through pipe.

[0025] The fifth resonant partition includes a ninth partition and a tenth partition that is connected to both the ninth and seventh partitions. The end of the ninth partition near the tenth partition is connected to the end of the tenth partition near the ninth partition. Both the ninth and tenth partitions are also connected to the first through pipe.

[0026] Furthermore, the reverse resonant channel includes:

[0027] The first channel is formed by the first connecting unit, the first partition, the second partition, the fourth partition, and the third partition.

[0028] The second passage is formed by the second partition, the fourth partition, the third partition, the sixth partition, and the fifth partition.

[0029] The third channel is formed by the third partition, the sixth partition, the fifth partition, the eighth partition, and the seventh partition.

[0030] The fourth channel is formed by the fifth partition, the eighth partition, the seventh partition, the tenth partition, and the ninth partition.

[0031] Furthermore, the entrance to the first channel is located near the first connecting unit.

[0032] The entrance to the second channel is located near the second connection unit.

[0033] The entrance to the third channel is close to the entrance side of the first channel and is adjacent to the entrance of the first channel;

[0034] The entrance to the fourth channel is close to the entrance side of the second channel and is adjacent to the entrance of the second channel.

[0035] Furthermore, the first connecting unit includes a first cover connected to the first through pipe and a second cover connected to the first cover, wherein the first cover is provided with a first thread;

[0036] The second connecting unit includes a third cover that is connected to both the first through pipe and the second partition, and the third cover is provided with a second thread.

[0037] Furthermore, the acoustic flow separation unit includes:

[0038] A first separation net is connected to the first through pipe and is installed at the entrance of the first channel;

[0039] The second separation net is connected to the first through pipe and is set at the entrance of the second channel;

[0040] The third separation mesh is connected to the first through pipe and is located at the entrance of the third channel;

[0041] The fourth separation mesh is connected to the first conduit and is located at the entrance of the fourth channel.

[0042] Furthermore, in the fourth channel:

[0043] The distance between the end of the ninth partition near the eighth partition and the eighth partition is the first gap, and the acoustic impedance model of the first gap is:

[0044]

[0045] Where i is the imaginary unit, ρ is the equivalent density of the medium, c is the equivalent speed of sound, and S A S is the cross-sectional area of ​​the first spacing. V The reference volume is given, k is the wavenumber, and h is the volume. A The distance between the first gap and the seventh partition is given by n, where n is the order, J0 is the 0th-order Bessel function of the first kind, Y0 is the 0th-order Bessel function of the second kind, and γ is the distance between the first and seventh partitions. rn For nth order radial wavenumber, For the nth order radially normalized wavenumber;

[0046] The distance between the end of the ninth partition near the eighth partition and the fifth partition is the second spacing, and the acoustic impedance model of the second spacing is:

[0047]

[0048] Where S is the area of ​​the second spacing, V is the reference volume, and h is the equivalent height. Let ξ be the wave function. rn Reference radial wavenumber;

[0049] The acoustic impedance model at the entrance of the fourth channel is as follows:

[0050]

[0051] Where J1 is a first-order Bessel function of the first kind, Y1 is a first-order Bessel function of the second kind, and R is the reference radius.

[0052] Furthermore, the acoustic resistance of the fourth separation mesh located at the entrance of the fourth channel, together with the acoustic resistance at the entrance of the fourth channel, constitutes the total acoustic resistance generated inside the fourth channel.

[0053] Furthermore, the model for the projection coefficient during the sound transmission process from the first cover to the third cover is as follows:

[0054]

[0055] In the formula, N is the number of resonant regions, and α n,m Approximately equal to 1, v equals e -ikz δ nm G is the Dirac selection function, and G is the Green's function;

[0056] The model for sound transmission loss during the transmission of sound from the first cover to the third cover is as follows:

[0057] STL = -20 × log 10 (|T|).

[0058] Compared to existing technologies, the acoustic metamaterial silencer for high-flow-rate pipelines provided by the first aspect of this invention achieves sound-flow separation in the first conduit within the first central channel during sound transmission from the first connecting unit to the second connecting unit. It also controls the fluid flow within the resonant unit, preventing eddies caused by the fluid impacting the inlets of each reverse resonant channel, thereby suppressing secondary noise radiation. Simultaneously, the sound-flow separation unit is integrated into each reverse resonant channel within the resonant unit. Because the channel paths of adjacent reverse resonant channels are opposite, broadband noise reduction is achieved. This avoids the need for multiple silencers connected in series axially, which would compromise the dimensional requirements for practical applications, thus enabling attenuation of noise at different frequencies. Attached Figure Description

[0059] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, with the same or corresponding reference numerals denoteing the same or corresponding parts, wherein:

[0060] Figure 1 A cross-sectional view of an acoustic metamaterial silencer for high-flow-rate pipes is schematically shown.

[0061] Figure 2 A schematic diagram of an acoustic metamaterial silencer for high-flow-rate pipes is shown.

[0062] Figure 3 An exploded view schematically illustrates an acoustic metamaterial silencer for high-flow-rate pipes;

[0063] Figure 4 A schematic cross-sectional view of the fourth channel is shown.

[0064] Figure 5 A schematic diagram illustrating the sound transmission loss of the present invention compared to a conventional expansion silencer of the same volume is shown.

[0065] Explanation of icon numbers:

[0066] 1. Resonant unit; 11. First resonant partition; 111. First partition; 112. Second partition; 12. Second resonant partition; 121. Third partition; 122. Fourth partition; 13. Third resonant partition; 131. Fifth partition; 132. Sixth partition; 14. Fourth resonant partition; 141. Seventh partition; 142. Eighth partition; 15. Fifth resonant partition; 151. Ninth partition; 152. Tenth partition;

[0067] 2. First connecting unit; 21. First cover; 22. Second cover; 23. First thread;

[0068] 3. First connecting pipe;

[0069] 4. Acoustic flow separation unit; 41. First separation mesh; 42. Second separation mesh; 43. Third separation mesh; 44. Fourth separation mesh;

[0070] 5. Second connecting unit; 51. Third cover; 52. Second thread;

[0071] 6. First passage;

[0072] 7. Second channel;

[0073] 8. Third Channel;

[0074] 9. Fourth channel; 91. First spacing; 92. Second spacing; 93. Entrance to the fourth channel. Detailed Implementation

[0075] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Unless otherwise specified, the techniques used in the embodiments are conventional means well known to those skilled in the art.

[0076] It should be noted that, unless otherwise stated, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. In this document, relational terms such as “first” and “second” are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms “connected,” “linked,” etc., should be interpreted broadly, for example, referring to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection via an intermediate medium. The terms “comprising,” “including,” or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase “comprising…” does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0077] This invention provides an acoustic metamaterial silencer for high-flow-rate pipelines, combined with... Figure 1 and Figure 2 as well as Figure 3An acoustic metamaterial silencer for high-flow-rate pipelines includes a resonant unit 1, reverse resonant channels, a first connecting unit 2, a second connecting unit 5, a first central channel, a first through-pipe 3, and an acoustic-flow separation unit 4. The reverse resonant channels are each located within the resonant unit 1, and the path of adjacent reverse resonant channels is opposite. The first connecting unit 2 is located at the upper part of the resonant unit 1 and connected to it. The second connecting unit 5 is located at the lower part of the resonant unit 1 and connected to it. The first central channel is formed by the resonant unit 1, the first connecting unit 2, and the second connecting unit 5. The first through-pipe 3 is located within the first central channel and connected to it. The acoustic-flow separation unit 4 is connected to the first through-pipe 3 and is located at the entrance of each reverse resonant channel.

[0078] In this embodiment, during the transmission of sound from the first connecting unit 2 to the second connecting unit 5, the sound-flow separation unit 4 achieves sound-flow separation in the first conduit 3 within the first central channel and controls the flow of fluid within the resonant unit 1, preventing eddies generated by the impact of fluid on the inlets of each reverse resonant channel, thereby suppressing secondary noise radiation. Simultaneously, the sound-flow separation unit 4 is integrated into each reverse resonant channel within the resonant unit 1. Since the channel paths between adjacent reverse resonant channels are opposite, broadband noise reduction is achieved, avoiding the need for additional axially connected silencers that would compromise the actual space requirements of the external dimensions in practical applications. This allows for the attenuation of noise at different frequencies.

[0079] In a specific embodiment, combined with Figure 1 and Figure 3 The resonant unit 1 includes a first resonant partition 11, a second resonant partition 12, a third resonant partition 13, a fourth resonant partition 14, and a fifth resonant partition 15. The first resonant partition 11 is connected to both the first connecting unit 2 and the second connecting unit 5. The second resonant partition 12 is located inside the first resonant partition 11, and is connected to the first through-tube 3 and simultaneously connected in the opposite direction to the first resonant partition 11. The third resonant partition 13 is located inside the second resonant partition 12, and is connected to both the first through-tube 3 and simultaneously connected in the opposite direction to the second resonant partition 12. The fourth resonant partition 14 is located inside the third resonant partition 13, and is connected to both the second resonant partition 12 and the first through-tube 3 and simultaneously connected in the opposite direction to the third resonant partition 13. The fifth resonant partition 15 is located inside the fourth resonant partition 14, and is connected to both the second resonant partition 12 and the first through-tube 3 and simultaneously connected in the opposite direction to the fourth resonant partition 14.

[0080] In this embodiment, the first resonant partition 11, the second resonant partition 12, the third resonant partition 13, the fourth resonant partition 14, and the fifth resonant partition 15 together increase the volume of the first conduit 3. More specifically, the second resonant partition 12 is located inside the first resonant partition 11 and is connected in the opposite direction to it; the third resonant partition 13 is located inside the second resonant partition 12 and is connected in the opposite direction to it; the fourth resonant partition 14 is located inside the third resonant partition 13 and is connected in the opposite direction to it; and the fifth resonant partition 15 is located inside the fourth resonant partition 14 and is connected in the opposite direction to it. Thus, in conjunction with the acoustic flow separation unit 4, wideband noise reduction is achieved, avoiding the need for multiple silencers connected in series axially, which would compromise the actual space requirements of the external dimensions in practical applications, thereby achieving attenuation of noise at different frequencies.

[0081] The longitudinal sections of the first resonant partition 11 and the fifth resonant partition 15 are both L-shaped, while the longitudinal sections of the second resonant partition 12, the third resonant partition 13, and the fourth resonant partition 14 are all T-shaped.

[0082] The connection methods between the resonant unit 1, the first connecting unit 2, the second connecting unit 5, the first through pipe 3 and the acoustic flow separation unit 4 include, but are not limited to, adhesive connection, snap-fit ​​connection and threaded connection, to ensure the overall airtightness of the acoustic metamaterial silencer used in high flow rate pipelines.

[0083] To achieve reverse connection between adjacent resonant partitions, thereby attenuating noise at different frequencies, in a specific embodiment, such as... Figure 1As shown, the first resonant partition 11 includes a first partition 111 and a second partition 112 connected to the first partition 111, and the end of the second partition 112 near the first partition 111 is connected to the end of the first partition 111 near the second partition 112. The second resonant partition 12 includes a third partition 121 and a fourth partition 122 connected to both the third partition 121 and the second partition 112, and the third partition 121 is also connected to the first conduit 3. The third resonant partition 13 includes a fifth partition 131 and a sixth partition 132 connected to both the fifth partition 131 and the third partition 121, and the fifth partition 131 is also connected to the first conduit 3. The fourth resonant partition 14 includes a seventh partition 141 and an eighth partition 142 connected to both the seventh partition 141 and the fifth partition 131, and the seventh partition 141 is also connected to the first conduit 3. The fifth resonant partition 15 includes a ninth partition 151 and a tenth partition 152 that is connected to both the ninth partition 151 and the seventh partition 141. The end of the ninth partition 151 near the tenth partition 152 is connected to the end of the tenth partition 152 near the ninth partition 151. Both the ninth partition 151 and the tenth partition 152 are also connected to the first conduit 3.

[0084] In a specific embodiment, such as Figure 1 As shown, the reverse resonant channel includes a first channel 6, a second channel 7, a third channel 8, and a fourth channel 9. The first channel 6 is formed by the first connecting unit 2, a first partition 111, a second partition 112, a fourth partition 122, and a third partition 121. The second channel 7 is formed by the second partition 112, the fourth partition 122, the third partition 121, the sixth partition 132, and the fifth partition 131. The third channel 8 is formed by the third partition 121, the sixth partition 132, the fifth partition 131, the eighth partition 142, and the seventh partition 141. The fourth channel 9 is formed by the fifth partition 131, the eighth partition 142, the seventh partition 141, the tenth partition 152, and the ninth partition 151.

[0085] The first channel 6, the second channel 7, the third channel 8, and the fourth channel 9 each form a separate resonant region.

[0086] In this embodiment, the terminal of the second channel 7 is located on the channel wall of the first channel 6, the terminal of the third channel 8 is located on the channel wall of the second channel 7, and the terminal of the fourth channel 9 is located on the channel wall of the third channel 8. Thus, in conjunction with the acoustic flow separation unit 4, wideband noise reduction is achieved, avoiding the need for additional axially connected silencers which would compromise the actual space requirements of the external dimensions in practical applications, thereby achieving attenuation of noise at different frequencies.

[0087] To further illustrate the entrances of each of the first channel 6, the second channel 7, the third channel 8, and the fourth channel 9, in a specific embodiment, as shown... Figure 1 As shown, the entrance to the first channel 6 is close to the side of the first connecting unit 2. The entrance to the second channel 7 is close to the side of the second connecting unit 5. The entrance to the third channel 8 is close to the entrance of the first channel 6 and is adjacent to the entrance of the first channel 6. The entrance to the fourth channel 9 is close to the entrance of the second channel 7 and is adjacent to the entrance of the second channel 7.

[0088] In a specific embodiment, combined with Figure 1 and Figure 2 as well as Figure 3 The first connecting unit 2 includes a first cover 21 connected to the first through pipe 3 and a second cover 22 connected to the first cover 21. The first cover 21 is provided with a first thread 23. The second connecting unit 5 includes a third cover 51 connected to both the first through pipe 3 and the second partition 112. The third cover 51 is provided with a second thread 52.

[0089] In this embodiment, after sound enters the first conduit 3 from the side of the first cover 21, it passes through the sound flow separation unit 4 and the reverse resonance channel, and finally exits from the first conduit 3 on the side of the third cover 51. The sound exiting from the first conduit 3 on the side of the third cover 51 has achieved broadband noise reduction, and avoids the need to connect multiple silencers in series axially, which would prevent the external dimensions from meeting the actual space requirements in practical applications. This achieves attenuation of noise at different frequencies.

[0090] The first thread 23 and the second thread 52 are respectively connected to the target pipe.

[0091] In a specific embodiment, combined with Figure 1 and Figure 3 The acoustic flow separation unit 4 includes a first separation mesh 41, a second separation mesh 42, a third separation mesh 43, and a fourth separation mesh 44. The first separation mesh 41 is connected to the first conduit 3 and is located at the entrance of the first channel 6. The second separation mesh 42 is connected to the first conduit 3 and is located at the entrance of the second channel 7. The third separation mesh 43 is connected to the first conduit 3 and is located at the entrance of the third channel 8. The fourth separation mesh 44 is connected to the first conduit 3 and is located at the entrance of the fourth channel 9.

[0092] In this embodiment, during the transmission of sound from the first cover 21 to the third cover 51, the first separating mesh 41 achieves sound-flow separation in the first pipe 3 within the first central channel and controls the flow of fluid within the first channel 6, preventing the fluid from impacting the inlet of the first channel 6 and generating eddies, thus suppressing secondary noise radiation at the inlet of the first channel 6. After passing through the first separating mesh 41, the sound then passes through the third separating mesh 43. The third separating mesh 43 achieves sound-flow separation in the first pipe 3 within the first central channel and controls the flow of fluid within the third channel 8, preventing the fluid from impacting the inlet of the third channel 8 and generating eddies, thus suppressing secondary noise at the inlet of the third channel 8. The sound is radiated through a series of separations. After passing through the third separation mesh 43, the sound then passes through the fourth separation mesh 44. The fourth separation mesh 44 achieves sound-flow separation within the first conduit 3 in the first central channel and controls the fluid flow within the fourth channel 9, preventing eddies caused by the fluid impacting the inlet of the fourth channel 9 and suppressing secondary noise radiation at the inlet of the fourth channel 9. The sound then passes through the fourth separation mesh 44 and then through the second separation mesh 42. The second separation mesh 42 achieves sound-flow separation within the first conduit 3 in the first central channel and controls the fluid flow within the second channel 7, preventing eddies caused by the fluid impacting the inlet of the second channel 7 and suppressing secondary noise radiation at the inlet of the second channel 7. Thus, secondary noise radiation is suppressed throughout the entire first conduit 3.

[0093] The first separation mesh 41, the second separation mesh 42, the third separation mesh 43, and the fourth separation mesh 44 are all wire mesh structures. In the radial direction of the first conduit 3, due to the strong diffraction of sound waves, the wire mesh structure generates low resistance to sound waves but high resistance to the fluid, thus achieving sound-flow separation. Simultaneously, because the wire mesh structure provides significant resistance to the fluid in the radial direction of the first conduit 3, it controls the fluid flow within the first channel 6, the second channel 7, the third channel 8, and the fourth channel 9. This reduces the impedance mismatch of the flow on the acoustic metamaterial silencer used in high-flow-rate pipes, avoids fluid impact at the inlets of the first channel 6, the second channel 7, the third channel 8, and the fourth channel 9, reduces eddy current generation, and thus suppresses secondary noise radiation. Furthermore, it controls the radial diffusion of the fluid in the first conduit 3, controlling pressure loss along the flow path.

[0094] In a specific embodiment, such as Figure 4 As shown, in channel 9:

[0095] The distance between the end of the ninth partition 151, which is closer to the eighth partition 142, and the eighth partition 142 is the first spacing 91. The acoustic impedance model of the first spacing 91 is:

[0096]

[0097] Where i is the imaginary unit, ρ is the equivalent density of the medium, c is the equivalent speed of sound, and S A S is the cross-sectional area of ​​the first spacing 91. V The reference volume is given, k is the wavenumber, and h is the volume. A The distance between the first spacing 91 and the seventh partition 141, n is the order, J0 is the 0th order Bessel function of the first kind, Y0 is the 0th order Bessel function of the second kind, and γ is the distance between the first spacing 91 and the seventh partition 141. rn For nth order radial wavenumber, For the nth order radially normalized wavenumber;

[0098] The distance between the end of the ninth partition 151, which is closer to the eighth partition 142, and the fifth partition 131 is the second spacing 92. The acoustic impedance model of the second spacing 92 is as follows:

[0099]

[0100] Where S is the area of ​​the second spacing 92, V is the reference volume, and h is the equivalent height. Let ξ be the wave function. rn Reference radial wavenumber;

[0101] The acoustic impedance model at the fourth channel entrance at point 93 is as follows:

[0102]

[0103] Where J1 is a first-order Bessel function of the first kind, Y1 is a first-order Bessel function of the second kind, and R is the reference radius.

[0104] In this embodiment, the acoustic impedance models for the first distance, the second distance, and the entrance of the fourth channel 9 are all the same as the acoustic impedance models for the corresponding positions in other channels. In other words, substituting the parameters from the corresponding positions in other channels into the acoustic impedance models yields the acoustic impedance at the corresponding positions in those other channels.

[0105] To further calculate the complete noise attenuation formed at the entrance of the fourth channel 9, in a specific embodiment, such as Figure 4 As shown, the acoustic resistance of the fourth separation mesh 44 located at the entrance of the fourth channel 9 and the acoustic resistance at the entrance of the fourth channel 9 together constitute the total acoustic resistance generated inside the fourth channel 9.

[0106] In this embodiment, the acoustic impedance of the fourth separation mesh 44 located at the entrance of the fourth channel 9 can be measured by simulation.

[0107] In a specific embodiment, such as Figure 4 As shown, the model for the projection coefficient during the sound transmission process from the first cover 21 to the third cover 51 is as follows:

[0108]

[0109] In the formula, N is the number of resonant regions, and α n,m Approximately equal to 1, v equals e -ikz δ nm G is the Dirac selection function, and G is the Green's function;

[0110] The model for sound transmission loss during the transmission of sound from the first cover 21 to the third cover 51 is as follows:

[0111] STL = -20log 10 (|T|).

[0112] In this embodiment, the first channel 6, the second channel 7, the third channel 8 and the fourth channel 9 radiate noise into the first conduit 3, and thus will interact with the noise radiated from the first conduit 3 into the first channel 6, the second channel 7, the third channel 8 and the fourth channel 9. Therefore, based on the projection coefficient model in the process of transmission from the first cover 21 to the third cover 51, the specific interaction values ​​can be obtained.

[0113] A model of sound transmission loss during the sound transfer process from the first cover 21 to the third cover 51 can derive a direct indicator for evaluating the performance of acoustic metamaterial silencers used in high-flow-rate pipelines. The sound transmission loss during the sound transfer process from the first cover 21 to the third cover 51 is significantly lower than that of a conventional expansion silencer of the same volume. Figure 5 As shown, the performance of the acoustic metamaterial silencer for high-flow-rate pipelines of the present invention is significantly improved.

[0114] In this invention, the acoustic metamaterial silencer for high-flow-rate pipes can control the radial diffusion of fluid and control the pressure loss of sound waves along the pipe within the first conduit 3.

[0115] Compared to traditional materials that are flammable and difficult to degrade, the substrates of acoustic metamaterials include, but are not limited to, biodegradable polylactic acid materials, metal materials, and wood materials.

[0116] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An acoustic metamaterial silencer for high-flow-rate pipelines, characterized in that, include: Resonant unit; Reverse resonant channels are respectively arranged in the resonant unit, and the channel paths between adjacent reverse resonant channels are opposite; A first connecting unit is disposed on the upper part of the resonant unit and connected to the resonant unit; The second connecting unit is disposed at the lower part of the resonant unit and is connected to the resonant unit; The first central channel is formed by the resonant unit, the first connecting unit, and the second connecting unit; The first conduit is disposed within the first central channel and connected to the first central channel; The acoustic-to-fluid separation unit is connected to the first conduit and is located at the entrance of each of the reverse resonant channels; The resonant unit includes: The first resonant partition is connected to both the first connecting unit and the second connecting unit. The second resonant partition is located inside the first resonant partition. The second resonant partition is connected to the first through pipe and is also connected to the first resonant partition in the opposite direction. The third resonant partition is located inside the second resonant partition. The second resonant partition is connected to the first through pipe and simultaneously connected to the second resonant partition in the opposite direction. The fourth resonant partition is located inside the third resonant partition. The second resonant partition is connected to the first through pipe and simultaneously connected to the third resonant partition in the opposite direction. The fifth resonant partition is located inside the fourth resonant partition. The second resonant partition is connected to the first through pipe and simultaneously connected to the fourth resonant partition in the opposite direction. The reverse resonant channel includes: The first channel is formed by the first connecting unit, the first partition, the second partition, the fourth partition, and the third partition. The second passage is formed by the second partition, the fourth partition, the third partition, the sixth partition, and the fifth partition. The third channel is formed by the third partition, the sixth partition, the fifth partition, the eighth partition, and the seventh partition. The fourth channel is formed by the fifth partition, the eighth partition, the seventh partition, the tenth partition, and the ninth partition. The first resonant partition includes a first partition and a second partition connected to the first partition, and the end of the second partition near the first partition is connected to the end of the first partition near the second partition. The second resonant partition includes the third partition and the fourth partition connected to both the third partition and the second partition, and the third partition is also connected to the first through pipe; The third resonant partition includes the fifth partition and the sixth partition connected to both the fifth partition and the third partition, and the fifth partition is also connected to the first through pipe; The fourth resonant partition includes the seventh partition and the eighth partition, which is connected to both the seventh partition and the fifth partition. The seventh partition is also connected to the first through pipe. The fifth resonant partition includes the ninth partition and the tenth partition, which is connected to both the ninth partition and the seventh partition. The end of the ninth partition near the tenth partition is connected to the end of the tenth partition near the ninth partition. Both the ninth partition and the tenth partition are also connected to the first through pipe. The entrance to the first channel is located near the first connecting unit. The entrance to the second channel is located near the second connection unit. The entrance to the third channel is close to the entrance side of the first channel and is adjacent to the entrance of the first channel; The entrance to the fourth channel is close to the entrance side of the second channel and is adjacent to the entrance of the second channel.

2. The acoustic metamaterial silencer for high-flow-rate pipelines according to claim 1, characterized in that, The first connecting unit includes a first cover connected to the first through pipe and a second cover connected to the first cover, wherein the first cover is provided with a first thread; The second connecting unit includes a third cover that is connected to both the first through pipe and the second partition, and the third cover is provided with a second thread.

3. The acoustic metamaterial silencer for high-flow-rate pipelines according to claim 1, characterized in that, The acoustic flow separation unit includes: A first separation net is connected to the first through pipe and is installed at the entrance of the first channel; The second separation net is connected to the first through pipe and is set at the entrance of the second channel; The third separation mesh is connected to the first through pipe and is located at the entrance of the third channel; The fourth separation mesh is connected to the first conduit and is located at the entrance of the fourth channel.

4. The acoustic metamaterial silencer for high-flow-rate pipelines according to claim 3, characterized in that, In the fourth channel: The distance between the end of the ninth partition near the eighth partition and the eighth partition is the first gap, and the acoustic impedance model of the first gap is: Where i is the imaginary unit, ρ is the equivalent density of the medium, c is the equivalent speed of sound, and S A S is the cross-sectional area of ​​the first spacing. V The reference volume is given, k is the wavenumber, and h is the volume. A The distance between the first gap and the seventh partition is given by n, where n is the order, J0 is the 0th-order Bessel function of the first kind, Y0 is the 0th-order Bessel function of the second kind, and γ is the distance between the first and seventh partitions. rn For nth order radial wavenumber, For the nth order radially normalized wavenumber; The distance between the end of the ninth partition near the eighth partition and the fifth partition is the second spacing, and the acoustic impedance model of the second spacing is: Where S is the area of ​​the second spacing, V is the reference volume, and h is the equivalent height. Let ξ be the wave function. rn Reference radial wavenumber; The acoustic impedance model at the entrance of the fourth channel is as follows: Where J1 is a first-order Bessel function of the first kind, Y1 is a first-order Bessel function of the second kind, and R is the reference radius.

5. The acoustic metamaterial silencer for high-flow-rate pipelines according to claim 4, characterized in that, The acoustic resistance of the fourth separation mesh located at the entrance of the fourth channel, together with the acoustic resistance at the entrance of the fourth channel, constitutes the total acoustic resistance generated inside the fourth channel.

6. The acoustic metamaterial silencer for high-flow-rate pipelines according to claim 2, characterized in that, The model for the projection coefficient during sound transmission from the first cover to the third cover is as follows: In the formula, N is the number of resonant regions, and α n, m =1, v equals e -ikz δ nm G is the Dirac selection function, and G is the Green's function; The model for sound transmission loss during the transmission of sound from the first cover to the third cover is as follows: 。

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