Fan type ventilation and sound insulation device based on Helmholtz resonant cavity and acoustic barrier

Abstract

The invention discloses a fan type ventilation and sound insulation device based on a Helmholtz resonant cavity and an acoustic barrier. The fan type ventilation and sound insulation device comprises a main body and a plurality of micro-cavity structure units, the microcavity structure units are distributed on the outer side of the main body in an axial symmetry mode in the circumferential direction of the main body, and the distances between the adjacent microcavity structure units are the same; each microcavity structure unit comprises a resonant cavity unit, a thin neck unit and a small arc-shaped unit; empty grooves are formed between the adjacent thin neck units, between the adjacent resonant cavity units and between the thin neck units and the resonant cavity units in the microcavity structure units. The acoustic barrier is formed by periodically arranging a plurality of fan type ventilation and sound insulation devices; the fan type ventilation sound insulation device and the acoustic barrier have a better sound insulation effect in a low-frequency band, can realize sound insulation of low-frequency resonance frequency under the condition of guaranteeing ventilation, have good ventilation performance, are compact in structure and easy to process, and have wide application prospects.

Description

Technical Field

[0001] The present invention relates to the field of a new generation of acoustic devices, and specifically relates to a fan-shaped ventilation and sound insulation device based on a Helmholtz resonance cavity, and also relates to an acoustic barrier. Background Art

[0002] Low-frequency noise (frequency range of 200 Hz to 2000 Hz) has the characteristics of long propagation distance, slow energy attenuation, and strong diffraction ability, which affects people's quality of life and working environment. Most conventional sound insulation means adopt a closed structure, such as a solid wall or sound-absorbing board. Although it can isolate noise to a certain extent, it also hinders air circulation and is not conducive to heat exchange and air ventilation. Therefore, in scenarios such as subway ventilation openings and equipment room entrances where both sound insulation and ventilation efficiency need to be ensured, traditional structures are difficult to meet the actual use requirements.

[0003] For this reason, in recent years, some integrated ventilation and sound insulation structure design schemes have emerged. Among them, the ventilation and sound insulation structure based on the Helmholtz resonance cavity principle has received wide attention because it can absorb sound waves in a specific frequency band. This type of structure mainly includes the following typical forms: (1) The planar array type Helmholtz resonance structure weakens sound waves of a specific frequency by setting a periodic resonance cavity array, but its structure volume is large, the air flow channel is narrow, and the ventilation efficiency is limited; (2) The spiral or maze type acoustic structure realizes sound insulation by using the phase delay effect brought by the extended sound wave propagation path, but its processing is complex, the structure is huge, and the low-frequency performance is still limited; (3) The folded structure design obtains a lower resonance frequency by increasing the structure length through spatial folding, but usually brings problems such as increased air flow resistance and poor structure regulation accuracy.

[0004] Generally speaking, the existing ventilation and sound insulation structures still have the following problems: First, the sound insulation effect in the low-frequency band (200 Hz to 500 Hz) is not ideal, and it is difficult to meet the noise reduction requirements in actual applications; second, the ventilation efficiency is low, and the dual performance of sound insulation and ventilation cannot be taken into account; third, the structure is complex and the manufacturing difficulty is large, which is not conducive to batch engineering applications. Therefore, there is an urgent need for a new type of ventilation and sound insulation device with better sound insulation effect in the low-frequency band, good ventilation performance at the same time, and a compact and easy-to-process structure. Summary of the Invention

[0005] The object of the present invention is to provide a fan-shaped ventilation and sound insulation device and an acoustic barrier based on a Helmholtz resonance cavity. By optimizing the shape and structural layout of the resonance cavity, while achieving effective sound insulation in the low-frequency band, good air circulation performance is maintained, and it has broad application prospects.

[0006] To achieve the above functions, the present invention designs a fan-shaped ventilation and sound insulation device based on a Helmholtz resonance cavity. The fan-shaped ventilation and sound insulation device is fixed on a substrate, and the spaces within a preset range from the upper and lower surfaces of the substrate are cavities. The fan-shaped ventilation and sound insulation device includes a main body 1 and a plurality of micro-cavity structure units. The cross-sectional shapes of the micro-cavity structure units are the same. The micro-cavity structure units are circumferentially arranged around the outside of the main body 1 in an axisymmetric manner, and the distances between adjacent micro-cavity structure units are the same. The micro-cavity structure unit includes a resonance cavity unit 2, a neck unit 3, and a small arc unit 4. Among them, the neck unit 3 is located on one side of the resonance cavity unit 2. One end of the neck unit 3 is fixedly connected to the resonance cavity unit 2 through the small arc unit 4, and the other end is fixedly connected to the main body 1. The thickness of the neck unit 3 is less than that of the resonance cavity unit 2. There are empty slots 5 between adjacent neck units 3, between adjacent resonance cavity units 2, and between the neck unit 3 and the resonance cavity unit 2 in the micro-cavity structure unit. The small arc unit 4 is fixedly connected to the main body 1. Each resonance cavity unit 2 and each empty slot 5 have a certain opening angle, and the width gradually increases in the direction away from the main body 1, and the opening angles of each resonance cavity unit 2 are the same. The opening angles of the empty slots 5 between adjacent resonance cavity units 2, the opening angles of the empty slots 5 between adjacent neck units 3, and the opening angles of the empty slots 5 between the neck unit 3 and the resonance cavity unit 2 are the same.

[0007] As a preferred technical solution of the present invention: the main body 1 is cylindrical.

[0008] As a preferred technical solution of the present invention: the thickness of the main body 1 is greater than the thickness of each micro-cavity structure unit.

[0009] As a preferred technical solution of the present invention: along the counterclockwise direction of the main body 1, the thickness of the resonance cavity unit 2 in each micro-cavity structure unit increases in turn.

[0010] As a preferred technical solution of the present invention: the thickness range of the resonance cavity unit 2 in the micro-cavity structure unit is 0.24 cm to 1.9 cm.

[0011] As a preferred technical solution of the present invention: the number range of the micro-cavity structure units is 4 to 8.

[0012] As a preferred technical solution of the present invention: the opening angles of the empty slots 5 between adjacent resonance cavity units 2, the opening angles of the empty slots 5 between adjacent neck units 3, and the opening angles of the empty slots 5 between the neck unit 3 and the resonance cavity unit 2 are 2 degrees.

[0013] As a preferred technical solution of the present invention: the neck unit 3 has a certain opening angle, and the width gradually increases in the direction away from the main body 1, and the opening angles of each neck unit 3 are the same.

[0014] As a preferred technical solution of the present invention: the angular range of the included angle of the necking unit 3 is 4 degrees to 8 degrees.

[0015] The present invention also designs an acoustic barrier, which uses the fan-shaped ventilation and sound insulation device based on the Helmholtz resonance cavity as a basic unit, splices the substrates of multiple fan-shaped ventilation and sound insulation devices with each other, and arranges and distributes each fan-shaped ventilation and sound insulation device periodically in the horizontal and vertical directions.

[0016] Beneficial effects: Compared with the prior art, the advantages of the present invention include: The present invention designs a fan-shaped ventilation and sound insulation device and an acoustic barrier based on the Helmholtz resonance cavity. By utilizing the resonance effect of the thickness-gradual microcavity structure, the sound insulation effect in the low-frequency band can be achieved at the sub-wavelength scale. This acoustic barrier has a good sound insulation effect and can well maintain air circulation, which is of great significance for the design and application of a new generation of acoustic devices. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of a fan-shaped ventilation and sound insulation device based on the Helmholtz resonance cavity provided by an embodiment of the present invention; Figure 1 In it: 1, main body; 2, resonance cavity unit; 3, necking unit; 4, small arc unit; 5, empty groove; Figure 2 is a schematic structural diagram of a microcavity structure unit provided by an embodiment of the present invention; Figure 3 is a three-dimensional view of a fan-shaped ventilation and sound insulation device based on the Helmholtz resonance cavity provided by an embodiment of the present invention; Figure 4 is a three-dimensional view of a microcavity structure unit provided by an embodiment of the present invention; Figure 5 is a distribution diagram of resonance modes in a microcavity structure at a resonance frequency of 309 Hz provided by an embodiment of the present invention; Figure 6 is a distribution diagram of resonance modes in a microcavity structure at a resonance frequency of 376 Hz provided by an embodiment of the present invention; Figure 7 is a distribution diagram of resonance modes in a microcavity structure at a resonance frequency of 436 Hz provided by an embodiment of the present invention; Figure 8 is a distribution diagram of resonance modes in a microcavity structure at a resonance frequency of 507 Hz provided by an embodiment of the present invention; Figure 9 is a schematic diagram of an actual application scenario of an acoustic barrier provided by an embodiment of the present invention; Figure 10It is the transmission coefficient spectrogram of the acoustic barrier provided by the embodiment of the present invention. Detailed implementation manners

[0018] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and cannot be used to limit the protection scope of the present invention.

[0019] The fan-shaped ventilation and sound insulation device based on the Helmholtz resonance cavity provided by the embodiment of the present invention, the fan-shaped ventilation and sound insulation device is fixed on the substrate, and the space within a preset range from the upper surface and the lower surface of the substrate is a cavity; the fan-shaped ventilation and sound insulation device includes a main body 1 and a plurality of micro-cavity structure units; the main body and the micro-cavity structure units are resin structures, and sample preparation can be realized by using 3D printing technology; the main body 1 is cylindrical, and the thickness of the main body 1 is greater than the thickness of each micro-cavity structure unit; the radius range of the main body 1 is 0.5 cm to 2 cm. In one embodiment, the radius of the main body 1 is 1 cm.

[0020] The cross-sectional shapes of each micro-cavity structure unit are the same. The micro-cavity structure units are circumferentially arranged around the outside of the main body 1 in an axisymmetric manner, and the distances between adjacent micro-cavity structure units are the same; the micro-cavity structure unit includes a resonance cavity unit 2, a neck unit 3, and a small arc unit 4. Among them, the neck unit 3 is located on one side of the resonance cavity unit 2. One end of the neck unit 3 is fixedly connected to the resonance cavity unit 2 through the small arc unit 4, and the other end is fixedly connected to the main body 1; the thickness of the neck unit 3 is less than that of the resonance cavity unit 2. Along the counterclockwise direction of the main body 1, the thickness of the resonance cavity unit 2 in each micro-cavity structure unit increases in turn; there are empty slots 5 between adjacent neck units 3, between adjacent resonance cavity units 2, and between the neck unit 3 and the resonance cavity unit 2 in the micro-cavity structure unit to form an air channel. The small arc unit 4 is fixedly connected to the main body 1; each resonance cavity unit 2 and each empty slot 5 have a certain opening angle, and the width gradually increases along the direction away from the main body 1, and the opening angles of each resonance cavity unit 2 are the same; the opening angles of the empty slots 5 between adjacent resonance cavity units 2, the opening angles of the empty slots 5 between adjacent neck units 3, and the opening angles of the empty slots 5 between the neck unit 3 and the resonance cavity unit 2 are the same.

[0021] The number range of the micro-cavity structure units is 4 to 8; the thickness range of the resonance cavity unit 2 in the micro-cavity structure unit is 0.24 cm to 1.9 cm.

[0022] The opening angles of the empty slots 5 between adjacent resonance cavity units 2, the opening angles of the empty slots 5 between adjacent neck units 3, and the opening angles of the empty slots 5 between the neck unit 3 and the resonance cavity unit 2 are 2 degrees.

[0023] The necked unit 3 has a certain opening angle, and its width gradually increases in the direction away from the main body 1. Moreover, the opening angles of all the necked units 3 are the same, and the range of the opening angle of the necked unit 3 is 4 degrees to 8 degrees.

[0024] Referring to Figure 1 , in one embodiment, the number of microcavity structure units is 8. Among them, the opening angle of the necked unit 3 is 4 degrees, the opening angle of each resonant cavity unit 2 is 37 degrees, and the opening angles of the slots 5 between adjacent resonant cavity units 2, the slots 5 between adjacent necked units 3, and the slots 5 between the necked unit 3 and the resonant cavity unit 2 are 2 degrees; the resonant cavity unit 2 is a trapezoid with non-parallel upper and lower bases. Figure 1 In , w represents the side length of the substrate, and h3 represents the distance between the edge of the substrate and the microcavity structure unit. l l represents the length of the necked unit 3. In one embodiment, l l = 2.5 cm; r is the radius of the main body 1.

[0025] Referring to Figure 2 , one end of the necked unit 3 is connected to the hypotenuse of the resonant cavity unit 2 through a small arc unit 4. The length of the small arc unit 4 is h4. In one embodiment, h4 = 0.5 mm; the thickness of the small arc unit 4 is the same as that of the main body 1. The three-dimensional view of the fan-shaped ventilation and sound insulation device based on the Helmholtz resonance cavity refers to Figure 3 , and the three-dimensional view of the microcavity structure unit refers to Figure 4 , Figure 3 In , the thickness of the main body 1 is 2h1. The distance between the top surface of the main body 1 and the top surface of the cavity, and the distance between the bottom surface of the main body 1 and the bottom surface of the cavity are both 2h1. The thickness of the overall cavity is 6h1. Figure 4 In , the thickness of the necked unit 3 is 2h2. In one embodiment, h2 = 0.3 cm. The thicknesses of each resonant cavity unit 2 in the counterclockwise direction along the circumference of the main body 1 are 2d0, 2d1, 2d2, 2d3, 2d4, 2d5, 2d6, and 2d7 respectively. In one embodiment, d0 to d7 are respectively: , , , , , , , .

[0026] The design scheme of the microcavity structure unit is the key to realizing sub-wavelength multi-frequency resonance in the present invention. Moreover, a single microcavity structure unit simultaneously supports multiple low-order resonance modes, which is of fundamental importance for realizing the design of an omnidirectional ventilation acoustic barrier structure in the low-frequency band.

[0027] The working principle of the fan-shaped ventilation and sound insulation device designed by the present invention is as follows: when sound waves enter the microcavity structure unit with a gradually changing thickness, the resonance cavity units 2 with different thicknesses excite low-order resonance modes at their respective corresponding frequency points, thereby absorbing and dissipating the sound wave energy and achieving the sound wave suppression effect in multiple frequency bands. Since these units have sub-wavelength characteristics, they can achieve sound insulation at multiple frequency points within a small structural scale. Among them, the resonance cavity unit 2 is responsible for the main sound energy storage and resonance, the neck unit 3 restricts air exchange and enhances the resonance coupling effect, and the small arc unit 4 is used for transitional connection and maintaining a continuous air channel.

[0028] Figures 5 to 8 They are respectively the resonance mode distribution diagrams in the microcavity structure at resonance frequencies of 309 Hz, 376 Hz, 436 Hz, and 507 Hz.

[0029] The embodiment of the present invention also provides an acoustic barrier, which uses the above-mentioned fan-shaped ventilation and sound insulation device based on the Helmholtz resonance cavity as the basic unit. The substrates of multiple fan-shaped ventilation and sound insulation devices are spliced with each other, and each fan-shaped ventilation and sound insulation device is arranged periodically in the horizontal and vertical directions. For the schematic diagram of the actual application scenario of the acoustic barrier, refer to Figure 9 , and for the transmission coefficient spectrum of the acoustic barrier, refer to Figure 10 .

[0030] In summary, the present invention proposes a fan-shaped ventilation and sound insulation device and an acoustic barrier based on the Helmholtz resonance cavity, and its core lies in a microcavity structure unit with a gradually changing thickness feature. This structure is composed of multiple resonance cavity units distributed in the circumferential direction of the main body. Each resonance cavity unit gradually changes its cavity thickness in the circumferential direction on the premise of maintaining the overall structural symmetry, so that different units have different effective resonance lengths and cavity volumes. This angular gradient design of the thickness enables a single sub-wavelength structure unit to simultaneously excite low-order resonance modes at multiple frequency points, thereby achieving the ability to suppress sound waves in multiple frequency bands or even wide frequency bands. By finely controlling the cavity length, width, and cavity thickness, high-efficiency sound energy capture performance can be obtained at a small structural scale, and it has a significant sound insulation effect. In addition, this structure adopts a hollow ventilation design, which can keep the air flowing naturally while effectively suppressing low-frequency noise, and is suitable for actual scenarios with high requirements for both ventilation and sound insulation performance, such as urban traffic air ducts, subway entrances and exits, and ventilation equipment rooms. Numerical simulation and simulation results show that this structure can achieve stable sound energy suppression in multiple low-frequency bands, and its sound insulation peak can be flexibly adjusted by adjusting geometric parameters. The present invention also has good scalability and tailoring properties. Users can customize the required sound insulation performance and ventilation capacity by adjusting parameters such as the number of resonance cavity units, angular distribution, and thickness change gradient according to the target frequency range, providing a new and efficient solution for the design of multi-frequency broadband sound insulation devices.

[0031] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. A fan-type ventilation and sound insulation device based on a Helmut Holtz resonance cavity, characterized in that: The fan-type ventilation sound insulation device is fixed on a substrate, and the space within a preset range from the upper surface and the lower surface of the substrate is a cavity; the fan-type ventilation sound insulation device comprises a main body (1), and a plurality of microcavity structure units; the cross-sectional shapes of the microcavity structure units are the same, the microcavity structure units are axially symmetrically arranged around the outside of the main body (1) along the circumference of the main body (1), and the distances between adjacent microcavity structure units are the same; the microcavity structure units comprise a resonant cavity unit (2), a thin neck unit (3), and a small arc unit (4); The thin neck unit (3) is located on one side of the resonant cavity unit (2); one end of the thin neck unit (3) is fixedly connected to the resonant cavity unit (2) via the small arc-shaped unit (4); the other end of the thin neck unit (3) is fixedly connected to the main body (1); and the thickness of the thin neck unit (3) is smaller than that of the resonant cavity unit (2); There are slots (5) between adjacent thin-neck units (3), between adjacent resonant cavity units (2), and between thin-neck units (3) and resonant cavity units (2) in the microcavity structure unit; each resonant cavity unit (2) and each slot (5) has a certain opening angle, and the width gradually increases along the direction away from the main body (1), and the opening angle of each resonant cavity unit (2) is the same; the opening angle of the slots (5) between adjacent resonant cavity units (2), the opening angle of the slots (5) between adjacent thin-neck units (3), and the opening angle of the slots (5) between the thin-neck unit (3) and the resonant cavity unit (2) are the same.

2. The fan-type ventilation and sound insulation device based on the Helmut Holtz resonance cavity according to claim 1 is characterized in that: The main body (1) is cylindrical.

3. The fan-type ventilation and sound insulation device based on the Helmut Holtz resonance cavity according to claim 1 is characterized in that: The thickness of the main body (1) is greater than the thickness of each microcavity structural unit.

4. The fan-type ventilation and sound insulation device based on the Helmut Holtz resonance cavity according to claim 1 is characterized in that: Along the counterclockwise direction of the main body (1), the thickness of the resonance cavity unit (2) in each microcavity structure unit increases successively.

5. The fan-type ventilation and sound insulation device based on the Helmut Holtz resonance cavity according to claim 4 is characterized in that: The thickness of the resonant cavity unit (2) in the microcavity structure unit ranges from 0.24 cm to 1.9 cm.

6. The fan-type ventilation and sound insulation device based on the Helmut Holtz resonance cavity according to claim 1, characterized in that: The number of the microcavity structural units ranges from 4 to 8.

7. The fan-type ventilation and sound insulation device based on the Helmut Holtz resonance cavity according to claim 1 is characterized in that: The angles of the slots (5) between adjacent resonant cavity units (2), the angles of the slots (5) between adjacent narrow neck units (3), and the angles of the slots (5) between the narrow neck unit (3) and the resonant cavity unit (2) are all 2 degrees.

8. The fan-type ventilation and sound insulation device based on the Helmut Holtz resonance cavity according to claim 1, characterized in that: The narrow neck unit (3) has a certain opening angle, and its width gradually increases in a direction away from the main body (1), and the opening angle of each narrow neck unit (3) is the same.

9. The fan-type ventilation and sound insulation device based on the Helmut Holtz resonance cavity according to claim 8, characterized in that: The opening angle of the narrow neck unit (3) ranges from 4 degrees to 8 degrees.

10. An acoustic barrier, comprising: a fan-type ventilation and sound insulation device based on a Helmut Holtz resonance cavity as claimed in any one of claims 1 to 9 as a basic unit, substrates of a plurality of fan-type ventilation and sound insulation devices are spliced ​​together, and the fan-type ventilation and sound insulation devices are periodically arranged and distributed in the horizontal and vertical directions.

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