Broadband sound absorption Helmholtz resonator

Abstract

The invention discloses a broadband sound-absorbing Helmholtz resonator. The broadband sound-absorbing Helmholtz resonator comprises a cavity, a sound-absorbing layer, a sound-absorbing layer and a sound-absorbing layer, the one or more partition plates are arranged in the cavity and divide the space in the cavity into a plurality of cavities, every two adjacent cavities are separated through one partition plate, and the partition plates are provided with communicating structures for communicating the two adjacent cavities; and the multiple neck pipe bodies communicate with the multiple cavities in a one-to-one correspondence mode, the multiple neck pipe bodies communicate with a pipeline system to be subjected to noise reduction in parallel, and the sectional areas of the multiple neck pipe bodies are different and / or the volumes of the multiple cavities are different. According to the broadband sound absorption Helmholtz resonator provided by the embodiment of the invention, good sound absorption capability can be kept in a continuously changing frequency range, and the broadband sound absorption Helmholtz resonator has the advantages of wide sound absorption frequency band, wide applicability and the like.

Description

Technical Field

[0001] The invention relates to the technical field of noise suppression, and in particular to a broadband sound-absorbing Helmholtz resonator. Background Art

[0002] The Helmholtz resonator is a passive sound absorption device that is widely used in industrial applications such as automobile exhaust sound absorption and combustion oscillation suppression.

[0003] The Helmholtz resonator in the related art consists of a thinner neck tube and a cavity connected thereto. The neck tube is connected to a system with noise suppression requirements. The noise sound wave propagates to the entrance of the neck tube and enters the resonator, causing phase change and energy loss.

[0004] The resonant frequency of the Helmholtz resonator is its main operating frequency. Based on its working principle, the Helmholtz resonator has a single resonant frequency determined by the structural dimensions. It has a good noise suppression effect near this frequency, but its noise suppression effect is very limited after deviating from this frequency. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a broadband sound-absorbing Helmholtz resonator, which can maintain good sound absorption capacity within a continuously changing frequency range and has the advantages of wide sound absorption frequency band and wide applicability.

[0006] To achieve the above-mentioned purpose, a broadband sound-absorbing Helmholtz resonator is proposed according to an embodiment of the first aspect of the present invention, and the broadband sound-absorbing Helmholtz resonator comprises: a cavity; one or more partitions, one or more of which are arranged in the cavity and divide the space in the cavity into a plurality of chambers, each two adjacent chambers are separated by a partition, and a connecting structure connecting the two adjacent chambers is provided on the partition; a plurality of neck tube bodies, the plurality of neck tube bodies are connected to the plurality of chambers one by one, the plurality of neck tube bodies are connected in parallel with the pipeline system to be noise reduced, the cross-sectional areas of the plurality of neck tube bodies are different and / or the volumes of the plurality of chambers are different.

[0007] The broadband sound-absorbing Helmholtz resonator according to the embodiment of the present invention can maintain good sound absorption capability within a continuously changing frequency range, and has the advantages of a wide sound absorption frequency band and wide applicability.

[0008] In addition, the broadband sound-absorbing Helmholtz resonator according to the above embodiment of the present invention may also have the following additional technical features:

[0009] According to one embodiment of the present invention, the cross-sectional area of ​​the connecting structure is S pThe effective dimension of the thickness of the partition is l ′ p , the cross-sectional area of ​​the neck tube connected to the i-th chamber is S ni , the effective length of the neck tube body connected to the i-th chamber is l ′ ni , the number of the chambers is N, then:

[0010] According to an embodiment of the present invention, the communication structure is a through hole provided on the partition.

[0011] According to an embodiment of the present invention, the diameter of the through hole is 0.5-50 mm.

[0012] According to an embodiment of the present invention, the communication structure is a gap provided on the partition.

[0013] According to an embodiment of the present invention, the length of the gap is 0.5-50 mm and the width is 0.1-40 mm.

[0014] According to an embodiment of the present invention, the slit is located at an end of the partition plate adjacent to the neck tube body, or at an end away from the neck tube body.

[0015] According to one embodiment of the present invention, the thickness of the partition is 1-40 mm.

[0016] According to an embodiment of the present invention, the cavity is a cylindrical cavity, and the partition is arranged along the radial direction of the cavity.

[0017] According to an embodiment of the present invention, the cross-section of the neck tube body is circular, and a plurality of the neck tube bodies are connected to the same end surface of the cavity.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0020] Figure 1 Schematic diagram of the structure of a broadband sound-absorbing Helmholtz resonator according to an embodiment of the present invention.

[0021] Figure 2 Schematic diagram of the structure of a broadband sound-absorbing Helmholtz resonator according to a specific embodiment of the present invention.

[0022] Figure 3Schematic diagram of the structure of a broadband sound-absorbing Helmholtz resonator according to a specific embodiment of the present invention.

[0023] Figure 4 Schematic diagram of the structure of a broadband sound-absorbing Helmholtz resonator according to a specific embodiment of the present invention.

[0024] Figure 5 Schematic diagram of sound absorption performance analysis of a broadband sound absorbing Helmholtz resonator according to a specific embodiment of the present invention.

[0025] Figure 6 Schematic diagram of sound absorption performance analysis of a broadband sound absorbing Helmholtz resonator according to a specific embodiment of the present invention.

[0026] Figure 7 1 is an experimental measurement curve of the sound absorption coefficient of a broadband sound absorbing Helmholtz resonator according to a specific embodiment of the present invention.

[0027] Figure numerals: broadband sound-absorbing Helmholtz resonator 1 , cavity 10 , chamber 11 , partition 20 , gap 21 , neck tube body 30 , pipeline system to be noise-reduced 2 , noise signal 3 . DETAILED DESCRIPTION

[0028] This application is made based on the discovery of the following facts and problems by the inventor of this application:

[0029] The resonant frequency of the Helmholtz resonator is its main operating frequency. Based on its working principle, the Helmholtz resonator has a single resonant frequency determined by the structural dimensions. It has a good noise suppression effect near this frequency, but its noise suppression effect is very limited after deviating from this frequency.

[0030] To this end, some Helmholtz resonators in the related art have been designed with structural optimization to have more resonant frequencies, such as setting more parallel cavity units, which to a certain extent broadens the effective operating frequency range of the Helmholtz resonator, but it is difficult to maintain good sound absorption performance within a continuously changing frequency range.

[0031] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0032] 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", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, 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 communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] The broadband sound absorbing Helmholtz resonator 1 according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0035] like Figure 1-Figure 7 As shown, the broadband sound-absorbing Helmholtz resonator 1 according to an embodiment of the present invention comprises a cavity 10 , one or more partitions 20 and a plurality of neck tubes 30 .

[0036] One or more partitions 20 are disposed in the cavity 10 and divide the space in the cavity 10 into a plurality of chambers 11. It should be understood that when there are two chambers 11, there can be one partition 20, and when there are three or more chambers 11, there can be multiple partitions 20.

[0037] Every two adjacent chambers 11 are separated by a partition 20 , and a connecting structure for connecting the two adjacent chambers 11 is provided on the partition 20 .

[0038] The multiple neck tube bodies 30 are connected to the multiple chambers 11 in one-to-one correspondence, and the multiple neck tube bodies 30 are connected in parallel with the pipeline system 2 to be noise reduced. The cross-sectional areas of the multiple neck tube bodies 30 are different and / or the volumes of the multiple chambers 11 are different.

[0039] Specifically, the partition 20 divides the cavity 10 into N chambers 11, and there are also N neck tube bodies 30. The N chambers 11 and the N neck tube bodies 30 together constitute N resonator structure units. All neck tube bodies 30 are connected to the same pipeline system 2 to be noise reduced. The noise signal 3 in the pipeline system 2 to be noise reduced is transmitted to the entrance of the neck tube body 30 and enters each resonator structure unit. There is a parallel combination relationship between the N resonator structure units.

[0040] By providing the connecting structure on the partition 20, two adjacent chambers 11 are coupled. The partition 20 between adjacent chambers 11 has a specific impedance characteristic (Z p ), which determines the coupling relationship between adjacent chambers 11.

[0041] The resonant frequency of the i-th resonator structure unit among the N resonator structure units is:

[0042] Where c is the speed of sound, S ni is the cross-sectional area of ​​the neck tube 30, l i ′ is the effective length of the neck tube considering the acoustic radiation effect of the neck port (l′ i = l i +λd i ,l i is the actual length of the neck tube 30, d i is the diameter of the neck tube 30 section, λ is the end correction factor, which is 8 / 3π), V i is the volume of the chamber 11. The resonator structure unit has a good noise suppression effect near the resonance frequency.

[0043] The impedance characteristics (Z p ) is defined as (taking the partition 20 between the i-th chamber 11 and the i+1-th chamber 11 as an example):

[0044] Among them, Z pi is the impedance characteristic of the i-th and i+1-th partitions 20, p i ′ and p i ′ +1 represent the pressure pulsation in the i-th and i+1-th chambers 11, respectively, u i ′ ,i+1 The impedance characteristic (Z) of the partition 20 is the velocity pulsation caused by the pressure difference on both sides. p ) determines the acoustic wave transmission coupling relationship between adjacent chambers 11.

[0045] By providing a connecting structure, the partition 20 has a specific impedance characteristic, which can make the adjacent chambers 11 have a coupling relationship, thereby achieving the dimensionless acoustic impedance of the resonator to satisfy a certain synergistic relationship, so as to obtain a Helmholtz resonator that can maintain good sound absorption effect within a continuously changing frequency range.

[0046] The synergistic relationship of the dimensionless acoustic impedance of the resonator is the condition for making the sound absorption coefficient close to the optimal value 1. The calculation relationship between the sound absorption coefficient of the Helmholtz resonator installed at the end of the pipeline system and its dimensionless acoustic impedance is:

[0047] Among them, Re(Z d ) is the dimensionless sound of the Helmholtz resonator, Im(Z d ) is the dimensionless acoustic reactance of the Helmholtz resonator. The condition for the maximum value of the sound absorption coefficient α is:

[0048] If this prerequisite is met, the value of the sound absorption coefficient of the Helmholtz resonator is only related to the dimensionless acoustic reactance:

[0049] At this time, the dimensionless acoustic impedance Im(Z d ) is closer to 0, the closer its sound absorption coefficient α is to the optimal value 1. The above two impedances are the synergistic relationship of acoustic impedance.

[0050] In this way, the broadband sound-absorbing Helmholtz resonator 1 can have the impedance synergy relationship within a continuously changing frequency range, and the sound absorption frequency band of the broadband sound-absorbing Helmholtz resonator 1 can be significantly widened.

[0051] According to the broadband sound-absorbing Helmholtz resonator 1 of the embodiment of the present invention, the cavity 10 is divided into a plurality of chambers 11 by setting a partition 20, and a plurality of neck tubes 30 with different cross-sectional areas and / or a plurality of chambers 11 with different volumes are set, and a plurality of resonator structural units are formed by using the plurality of neck tubes 30 and the plurality of chambers 11, and each resonator structural unit has a different resonant frequency, which can have a good noise suppression effect near a plurality of different resonant frequencies.

[0052] Furthermore, by providing the connecting structure on the partition 20 and connecting two adjacent chambers 11 by using the connecting structure, compared with the Helmholtz resonator in the related art, the two adjacent chambers 11 can be coupled, so that the wide-band sound-absorbing Helmholtz resonator 1 has an impedance synergistic relationship, and the wide-band sound-absorbing Helmholtz resonator 1 can have a good noise reduction and sound absorption effect within a continuously changing frequency range, thereby improving the applicability of the wide-band sound-absorbing Helmholtz resonator 1.

[0053] Therefore, the broadband sound-absorbing Helmholtz resonator 1 according to the embodiment of the present invention can maintain good sound absorption capability within a continuously changing frequency range, and has the advantages of a wide sound absorption frequency band and wide applicability.

[0054] The broadband sound absorbing Helmholtz resonator 1 according to a specific embodiment of the present invention will be described below with reference to the accompanying drawings.

[0055] In some specific embodiments of the present invention, Figure 1-Figure 7 As shown, the broadband sound-absorbing Helmholtz resonator 1 according to an embodiment of the present invention comprises a cavity 10 , one or more partitions 20 and a plurality of neck tubes 30 .

[0056] Advantageously, the cross-sectional area of ​​the connecting structure is S p The effective thickness of the partition 20 is l' p , the cross-sectional area of ​​the neck tube 30 connected to the i-th chamber 11 is S ni , the effective length of the neck tube 30 connected to the i-th chamber 11 is l′ ni , the number of chambers 11 is N, then:

[0057] It should be understood that the "effective size" and "effective length" are the effective size and effective length corrected by taking into account the effect of port sound radiation. Those skilled in the art can calculate based on the actual size. For example, the effective length of the neck tube 30 is l' ni , l′ ni = l i +λd i ,l i is the actual length of the neck tube 30, d i is the cross-sectional diameter of the neck tube body 30, λ is the end correction factor, which is 8 / 3π.

[0058] Specifically, the dimensionless acoustic impedance Im(Z d ) is closer to 0, the closer its sound absorption coefficient α is to the optimal value 1. By setting a connecting structure on the partition 20, the Helmholtz resonator satisfies the impedance coordination relationship, and by adjusting the size parameters of the connecting structure, that is, the ratio of the length to the cross-sectional area of ​​the neck of the connecting structure and the parallel combination resonator structure unit has a considerable order of magnitude:

[0059] Thus, the partition 20 can be made to have a specific impedance characteristic Z by adjusting the size parameters of the connecting structure. p , so that there is an extremely weak coupling relationship between adjacent chambers 11, so that the broadband sound-absorbing Helmholtz resonator 1 can achieve good sound absorption and noise reduction effects at continuously changing frequencies, thereby obtaining a Helmholtz resonator with broadband sound absorption capability.

[0060] In some embodiments, the connecting structure is a through hole (not shown) provided on the partition plate, which can facilitate the processing of the connecting structure, facilitate the connection of two adjacent chambers 11, and facilitate the formation of a coupling structure.

[0061] Optionally, the diameter of the through hole is 0.5-50 mm. This can facilitate the formation of an extremely weak coupling structure, facilitate the formation of an impedance coordination relationship, and facilitate the broadband sound-absorbing Helmholtz resonator 1 to have a continuously changing sound-absorbing and noise-reducing frequency band.

[0062] In other embodiments, Figure 4 As shown, the communication structure is a gap 21 provided on the partition plate. This also facilitates the communication of two adjacent chambers 11 and forms a coupling structure.

[0063] Optionally, the length of the gap 21 is 0.5-50 mm and the width is 0.1-40 mm. This can facilitate the formation of an extremely weak coupling structure, facilitate the formation of an impedance coordination relationship, and facilitate the broadband sound-absorbing Helmholtz resonator 1 to have a continuously changing sound-absorbing and noise-reducing frequency band.

[0064] Specifically, Figure 4 As shown, the gap 21 is located at one end of the partition adjacent to the neck tube body 30, or at one end away from the neck tube body 30. This can further facilitate the formation of an extremely weak coupling structure and further facilitate the formation of an impedance coordination relationship.

[0065] Optionally, the thickness of the partition 20 is 1-40 mm. This can further facilitate the formation of an extremely weak coupling structure and further facilitate the formation of an impedance coordination relationship.

[0066] Specifically, Figure 1-Figure 4 As shown, the cavity 10 is a cylindrical cavity, and the partition 20 is arranged along the radial direction of the cavity. This can facilitate the processing of the cavity 10 and the arrangement of the partition 20.

[0067] More specifically, Figure 1-Figure 4 As shown, the cross section of the neck tube body 30 is circular, and a plurality of neck tube bodies 30 are connected to the same end surface of the cavity 10. This makes it easier to arrange the neck tube body 30.

[0068] In some embodiments, the broadband sound-absorbing Helmholtz resonator 1 is installed at the end of the pipe system 2 to be noise-reduced with an inner diameter of 50 mm, the cavity 10 has a diameter of 60 mm and a height of 100 mm, and the cavity 10 is divided into four equal parts by a partition with a thickness of 1 mm. The length of the neck tube body 30 matched with the four chambers 11 is 30 mm, and the diameters of the four neck tube bodies 30 are 6 mm, 8 mm, 10 mm, and 12 mm respectively. The connecting structure is a circular through hole with a hole diameter of 0.6 mm. Figure 5As shown, the broadband sound-absorbing Helmholtz resonator 1 can have a stable and good sound-absorbing effect in the frequency range of 210-330 Hz.

[0069] In other embodiments, the broadband sound-absorbing Helmholtz resonator 1 is installed at the end of the pipe system 2 to be noise-reduced with an inner diameter of 50 mm, the cavity 10 has a diameter of 60 mm and a height of 100 mm, and the cavity 10 is divided into 5 equal parts by a partition with a thickness of 1 mm, and the length of the neck tube body 30 matched with the five chambers 11 is 30 mm, and the diameters of the five neck tube bodies 30 are 4 mm, 5 mm, 6 mm, 8 mm, and 10 mm respectively. The connecting structure is a circular through hole with a hole diameter of 0.6 mm. Figure 6 As shown, the broadband sound-absorbing Helmholtz resonator 1 can have a stable and good sound-absorbing effect within the frequency range of 180-360 Hz.

[0070] In other embodiments, the cavity 10 has a diameter of 60 mm and a height of 100 mm, and the cavity 10 is divided into two equal parts by a partition with a thickness of 1 mm, and the length of the neck tubes 30 respectively matched with the two chambers 11 is 30 mm, and the diameters of the two neck tubes 30 are 6 mm and 12 mm respectively, and the connecting structure is a circular through hole with a hole diameter of 1 mm. Figure 7 As shown, the experimental measurement results show that the broadband sound-absorbing Helmholtz resonator 1 can maintain a sound absorption coefficient above 0.9 in the frequency range of 150-230 Hz, and has a stable and reliable broadband sound absorption capability.

[0071] Other structures and operations of the broadband sound-absorbing Helmholtz resonator 1 according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0072] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0073] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A broadband sound-absorbing Helmholtz resonator, characterized in that: include: Cavity; One or more partitions, one or more partitions are arranged in the cavity and divide the space in the cavity into a plurality of chambers, each two adjacent chambers are separated by one partition, and a connecting structure for connecting two adjacent chambers is provided on the partition; Multiple neck tube bodies, the multiple neck tube bodies are connected to the multiple chambers one by one, the multiple neck tube bodies are connected in parallel with the pipeline system to be noise reduced, the cross-sectional areas of the multiple neck tube bodies are different and / or the volumes of the multiple chambers are different.

2. The broadband sound-absorbing Helmholtz resonator according to claim 1, characterized in that: The cross-sectional area of ​​the connecting structure is S p The effective dimension of the thickness of the partition is l ′ p The cross-sectional area of ​​the neck tube connected to the i-th chamber is S ni , the effective length of the neck tube body connected to the i-th chamber is l ′ ni , the number of the chambers is N, then:

3. The broadband sound-absorbing Helmholtz resonator according to claim 1, characterized in that: The communication structure is a through hole arranged on the partition.

4. The broadband sound-absorbing Helmholtz resonator according to claim 3, characterized in that: The diameter of the through hole is 0.5-50 mm.

5. The broadband sound-absorbing Helmholtz resonator according to claim 1, characterized in that: The communication structure is a gap arranged on the partition.

6. The broadband sound-absorbing Helmholtz resonator according to claim 5, characterized in that: The length of the slit is 0.5-50 mm and the width is 0.1-40 mm.

7. The broadband sound-absorbing Helmholtz resonator according to claim 5, characterized in that: The slit is located at an end of the partition plate adjacent to the neck tube body, or at an end away from the neck tube body.

8. The broadband sound-absorbing Helmholtz resonator according to claim 1, characterized in that: The thickness of the separator is 1-40 mm.

9. The broadband sound-absorbing Helmholtz resonator according to claim 1, characterized in that: The cavity is a cylindrical cavity, and the partition is arranged along the radial direction of the cavity.

10. The broadband sound-absorbing Helmholtz resonator according to claim 9, characterized in that: The cross section of the neck tube body is circular, and a plurality of the neck tube bodies are connected to the same end surface of the cavity.

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