Helmholtz resonator with neck embedded ring

Abstract

The invention discloses a neck embedded ring type Helmholtz resonator, which relates to the technical field of low-frequency sound absorption structures and comprises a resonator main body, an embedded neck and a porous material lining. The resonator main body comprises an outer wall surface and a closed cavity; the embedded neck part penetrates through the top wall surface of the main body and comprises a neck part wall surface and an internal periodic convex ring structure; the porous material lining is attached to the inner wall of the closed cavity, and a first gap is formed between the porous material lining and the wall face of the neck. According to the resonator, the sound energy dissipation capacity and parameter harmonility are improved through the neck circular ring, the low-frequency sound absorption capacity is enhanced through the porous material in the cavity, the sound absorption peak value and frequency can be regulated and controlled by adjusting the parameters of the neck and the circular ring and selecting the type of the porous material, and the resonator is simple in structure, wide in application and beneficial to production.

Description

Technical Field

[0001] This invention relates to the field of low-frequency sound-absorbing structure technology, specifically to a neck-mounted ring-type Helmholtz resonator. Background Technology

[0002] The Helmholtz resonator is a resonant sound-absorbing structure that can be considered an acoustic mass-spring system. The air in the neck acts as the mass, and the air inside the cavity acts as the spring. When the frequency of the incident sound wave is close to the natural frequency of the structure, the sound wave induces Helmholtz resonance, resulting in sound energy dissipation and sound absorption. Due to its excellent low-frequency sound absorption performance, tunable absorption peak frequency, and small structural thickness, it has become a popular research subject in low-frequency noise control in recent years. However, the limited structural parameters of the classic Helmholtz resonator unit restrict the adjustment range of the absorption peak frequency, and its sound energy dissipation is mainly concentrated in the neck, resulting in a very low sound energy dissipation ratio in the cavity, which occupies a larger volume of the unit. Therefore, an improved Helmholtz resonator with a periodically embedded ring in the neck and a porous material filled inside the cavity is designed to address these issues. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a neck-entangled ring Helmholtz resonator.

[0004] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: A neck-mounted ring-type Helmholtz resonator, comprising: The resonator body includes the resonator outer wall and the enclosed cavity enclosed by the resonator outer wall; An embedded neck is provided through the top wall of the resonator body, including the neck wall and a periodic convex ring structure provided inside the neck wall; A porous material liner is tightly fitted to the inner wall of the enclosed cavity and has a first gap between it and the neck wall.

[0005] Preferably, the periodic convex ring structure consists of a plurality of rings spaced apart along the axial direction of the embedded neck.

[0006] Preferably, the rings are tightly fitted to the inner wall of the neck wall, the upper surface of the uppermost ring is in the same plane as the upper surface of the neck wall, and the lower surface of the lowermost ring is in the same plane as the lower surface of the neck wall.

[0007] More preferably, the periodic convex ring structure has at least two rings, and the width, thickness and spacing between adjacent rings are the same for each ring.

[0008] More preferably, the neck wall is a thin-walled cylinder with a central perforation.

[0009] Preferably, there is a second gap between the bottom surface of the embedded neck and the inner bottom surface of the resonator body, and the first gap communicates with the second gap.

[0010] Preferably, the outer wall of the resonator is a cuboid shell with a circular perforation at the center of its top wall, through which the embedded neck is disposed.

[0011] Preferably, the porous material liner is a block whose outer contour matches the internal shape of the resonator body, and has a cylindrical perforation at the center that is coaxial with the embedded neck, wherein the diameter of the circular perforation is smaller than the diameter of the cylindrical perforation.

[0012] Preferably, the outer wall surface, neck wall surface, and periodic convex ring structure of the resonator are all made of 3D printed photosensitive resin material.

[0013] Preferably, the porous material liner is made of polyurethane porous material.

[0014] Compared to existing technologies, the improved Helmholtz resonator of the present invention, characterized by a periodically embedded ring in the neck and a porous material filling the cavity, offers the following advantages: 1. In application, the top surface of the unit with circular perforations is aligned with the noise source, and sound waves enter the resonator through the perforations on the top wall. The incident sound waves at a specific frequency first cause resonance in the air at the neck of the resonator, resulting in significant sound energy dissipation. Subsequently, some of the sound waves entering the cavity are further absorbed by the porous material within the cavity. The periodically embedded neck ring improves the sound energy dissipation capability of the resonator neck to a certain extent and significantly enhances the parameter tunability of the unit. The porous material lining within the cavity further improves the low-frequency sound absorption capability of the resonator, achieving near-perfect subwavelength low-frequency sound absorption in an ultra-thin structure.

[0015] 2. The present invention allows for flexible control of the sound absorption peak value and frequency by adjusting the inner diameter of the neck, the width of the ring, the thickness of the ring, the spacing between the rings, the number of rings, and the type of porous material selected.

[0016] 3. All structures in this invention are centrally symmetrical, simple in structure, widely applicable, and easy to manufacture and process. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the neck-mounted ring-type Helmholtz resonator of the present invention.

[0018] Figure 2 This is a schematic diagram of the internal structure of the neck-mounted Helmholtz resonator of the present invention.

[0019] Figure 3This is a schematic diagram showing the internal structural dimensions of the neck-mounted Helmholtz resonator of the present invention.

[0020] Figure 4 This is a graph showing the test results of the sound absorption capability of the neck-mounted Helmholtz resonator of the present invention.

[0021] Reference numerals in the attached figures: 1-Resonator body; 101-Resonator outer wall; 102-Circular perforation; 2-Embedded neck; 201-Neck wall; 202-Ring; 3-Porous material liner; 301-Cylindrical perforation; 4-First gap; 5-Second gap. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples. However, it should be understood that the accompanying drawings are for illustrative purposes only and should not be construed as limiting the present patent. For better illustration of this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable that some well-known structures and their descriptions may be omitted in the drawings for those skilled in the art. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting the present patent.

[0023] like Figures 1-3 As shown, this embodiment provides a neck-embedded ring Helmholtz resonator, including: a resonator body 1, an embedded neck 2, and a porous material liner 3.

[0024] In some embodiments, the resonator body 1 includes a resonator outer wall surface 101 and a closed cavity enclosed by the resonator outer wall surface 101. Specifically, the resonator outer wall surface 101 is a cuboid shell with a circular perforation 102 at the center of its top wall surface, through which the embedded neck 2 is disposed.

[0025] In some embodiments, the embedded neck 2 is disposed through the top wall of the resonator body 1, including a neck wall 201 and a periodic convex ring structure disposed inside the neck wall 201.

[0026] Specifically, the neck wall 201 is a thin-walled cylinder with a central perforation, and the periodic convex ring structure consists of multiple rings 202 spaced apart along the axial direction of the embedded neck 2. The rings 202 are tightly fitted to the inner wall of the neck wall 201. The upper surface of the uppermost ring 202 is on the same plane as the upper surface of the neck wall 201, and the lower surface of the lowermost ring 202 is on the same plane as the lower surface of the neck wall 201. This design ensures the integrity and stability of the convex ring structure and the neck wall, and the position of the rings ensures uniform stress on the neck structure, facilitating regular resonance of sound waves in the neck and improving sound energy dissipation efficiency.

[0027] Furthermore, the periodic convex ring structure comprises at least two rings 202, and the width, thickness, and spacing of each ring 202 are identical. By using uniform dimensional parameters to ensure the periodicity of the convex ring structure, it is easy to adjust the sound absorption performance by changing parameters such as the number and spacing, thereby enhancing the adjustability of the sound absorption peak frequency.

[0028] Furthermore, the resonator's outer wall 101, neck wall 201, and periodic convex ring structure are all made of 3D-printed photosensitive resin material. 3D printing technology is suitable for processing complex structures such as periodic convex rings, and the photosensitive resin material is compatible with the printing process, reducing production difficulty and facilitating mass production. The embedded neck 2 is integrally formed with the top wall of the resonator using 3D printing technology. The four side walls and bottom wall of the resonator are also integrally formed using 3D printing technology and filled with porous material lining. The top wall with the embedded neck 2 is then placed on top, and finally, glue or other fillers are used to seal the gaps between the top and side walls to ensure no sound leakage.

[0029] In the above structure, the periodic convex ring structure of the embedded neck (composed of multiple axially spaced rings) can significantly improve the sound energy dissipation capability of the resonator neck, while also increasing the adjustable structural parameters (such as the number, width, thickness, and spacing of the rings). This significantly expands the adjustment range of the sound absorption peak frequency, overcoming the shortcomings of traditional Helmholtz resonators with few parameters and limited adjustment range, and realizing flexible control of sound absorption performance.

[0030] In some embodiments, the porous material liner 3 is tightly fitted to the inner wall of the enclosed cavity and has a first gap 4 between it and the neck wall 201. A second gap 5 is formed between the bottom surface of the embedded neck 2 and the inner bottom surface of the resonator body 1, and the first gap 4 and the second gap 5 communicate with each other. The design of the first and second gaps provides a channel for sound waves to travel from the neck to the cavity, ensuring that sound waves can efficiently enter the cavity and be absorbed by the porous material, thus improving the overall sound absorption efficiency.

[0031] Specifically, the porous material liner 3 is a block whose outer contour matches the internal shape of the resonator body 1, and it has a cylindrical perforation 301 coaxial with the embedded neck 2 at its center. The diameter of the circular perforation 102 is smaller than the diameter of the cylindrical perforation 301. The porous material liner 3 is made of polyurethane porous material, which is easy to manufacture. Polyurethane material is easy to produce, and the shape and size design of the liner ensures its adaptability to the neck and body. The coaxial perforation and diameter relationship ensure that sound waves can smoothly enter the cavity, enhancing the sound absorption effect.

[0032] In the aforementioned structure, the porous material lining (such as porous polyurethane material) attached to the inner wall of the sealed cavity can perform secondary absorption of sound waves entering the cavity, forming a synergistic effect with the resonance dissipation of the neck, further enhancing the low-frequency sound absorption performance of the resonator. Combined with the neck structure design, subwavelength low-frequency quasi-perfect sound absorption of the ultra-thin structure was finally achieved. In simulation tests, the sound absorption coefficient reached 0.947 at 124Hz, verifying the excellent low-frequency sound absorption effect.

[0033] The sound absorption capability of this sound-absorbing structure will be explained below with the help of simulation.

[0034] In the provided demonstration structure, the number of periodically embedded rings is 8.

[0035] The outer diameter, inner diameter, thickness, spacing, and number of the periodically embedded rings in the above structure can be appropriately changed; the configuration shown in this demonstration is merely a special case.

[0036] This invention will provide a set of structural and material parameters to verify the beneficial effects of the invention, including the following: (1) The side length L of the upper surface of the resonator is 40 mm and the height H is 50 mm.

[0037] (2) The thickness of the top wall of the resonator t1, the thickness of the side wall t2, the thickness of the bottom wall t3, and the thickness of the neck wall t n All are 1 mm.

[0038] (3) The diameter d of the cylindrical perforation on the porous material liner p It is 13.3 mm.

[0039] (4) Inner diameter d of the embedded neck w The diameter is 6.2 mm, and the width of the ring is r. h and the thickness of the ring l r All are 1mm, and the distance between the rings is l. w It is 4mm.

[0040] (5) The sound absorption model was constructed using the multiphysics coupling analysis software COMSOL Multiphysics. This invention only considers plane waves incident perpendicularly. An incident sound field is set above the sound absorption structure, and correspondingly, the outer wall of the resonator, the porous material lining inside the cavity, the neck wall, and the periodically embedded rings in the neck are constructed one by one in the sound absorption structure region. Among them, the incident sound field and the porous material domain are defined as the pressure acoustic domain, the air in the neck and the air in the perforations of the porous material are defined as the thermoviscous acoustic domain, and the outer wall of the resonator, the neck wall, and the periodically embedded rings in the neck are defined as the solid mechanics domain.

[0041] (6) The top of the incident sound field is set as a plane wave radiation, and the plane wave is incident perpendicularly to the sound-absorbing structure. The sound wave transmission of the sound-absorbing structure is ignored, and the bottom and side surfaces of the outer wall of the resonator are set as fixed constraints.

[0042] (7) The top and bottom covers are made of photosensitive resin, and its elastic modulus is [missing information]. ,density Poisson's ratio Incident sound field and air density in resonator speed of sound Dynamic viscosity thermal conductivity Constant pressure heat capacity Specific heat rate .

[0043] (8) The sound absorption coefficient can be obtained by solving the finite element model using COMSOL Multiphysics software. The calculated sound wave frequency range is 100 Hz-150 Hz, with a step size of 1 Hz.

[0044] like Figure 4 As shown, the sound-absorbing structure designed in this invention achieves a sound absorption coefficient of 0.947 at 124 Hz, demonstrating excellent low-frequency sound absorption capability.

[0045] In summary, improving the tunability of the near-perfect absorption peak of a sound-absorbing structure has always been a challenge in sound-absorbing structure design. This invention periodically embeds a circular ring in the neck of a classic Helmholtz resonator, significantly increasing the structural parameters available for design. At the same time, filling the cavity with porous material ensures its low-frequency sound absorption performance, causing the absorption peak to shift significantly to low frequencies and possessing excellent tunability. This overcomes the defect that the near-perfect absorption peak of a classic Helmholtz resonator is difficult to adjust over a wide frequency band, and the structure is simple and easy to manufacture.

[0046] Based on the description and accompanying drawings of this invention, those skilled in the art can readily manufacture or use a neck-ring Helmholtz resonator of this invention and achieve the positive effects described herein.

[0047] Unless otherwise specified, in this invention, terms such as "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe orientation or positional relationships in this invention are for illustrative purposes only and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood in conjunction with the accompanying drawings and according to the specific circumstances.

[0048] Unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A neck-mounted ring-type Helmholtz resonator, characterized in that, include: The resonator body (1) includes the resonator outer wall (101) and the closed cavity enclosed by the resonator outer wall (101); An embedded neck (2) is provided through the top wall of the resonator body (1), including a neck wall (201) and a periodic convex ring structure provided inside the neck wall (201); A porous material liner (3) is tightly fitted to the inner wall of the closed cavity and has a first gap (4) between it and the neck wall (201).

2. The neck-ring type Helmholtz resonator according to claim 1, characterized in that: The periodic convex ring structure consists of multiple rings (202) spaced apart along the axial direction of the embedded neck (2).

3. The neck-mounted ring-type Helmholtz resonator according to claim 2, characterized in that: The ring (202) is in close contact with the inner wall of the neck wall (201). The upper surface of the uppermost ring (202) is in the same plane as the upper surface of the neck wall (201), and the lower surface of the lowermost ring (202) is in the same plane as the lower surface of the neck wall (201).

4. The neck-ring type Helmholtz resonator according to claim 2 or 3, characterized in that: The periodic convex ring structure has at least two rings (202), and the width, thickness and spacing of each ring (202) are the same.

5. The neck-ring type Helmholtz resonator according to claim 1, 2 or 3, characterized in that: The neck wall (201) is a thin-walled cylinder with a central perforation.

6. The neck-mounted ring-type Helmholtz resonator according to claim 1, characterized in that: There is a second gap (5) between the bottom surface of the embedded neck (2) and the inner bottom surface of the resonator body (1), and the first gap (4) communicates with the second gap (5).

7. The neck-ring type Helmholtz resonator according to claim 1, characterized in that: The outer wall (101) of the resonator is a cuboid shell with a circular perforation (102) at the center of its top wall. The embedded neck (2) is arranged through the circular perforation (102).

8. The neck-ring type Helmholtz resonator according to claim 7, characterized in that: The porous material liner (3) is a block whose outer contour matches the internal shape of the resonator body (1), and has a cylindrical perforation (301) coaxial with the embedded neck (2) at the center. The diameter of the circular perforation (102) is smaller than the diameter of the cylindrical perforation (301).

9. The neck-ring type Helmholtz resonator according to claim 1, characterized in that: The outer wall (101), neck wall (201), and periodic convex ring structure of the resonator are all made of 3D printed photosensitive resin material.

10. The neck-ring type Helmholtz resonator according to claim 1, characterized in that: The porous material liner (3) is made of polyurethane porous material.

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