A broadband ventilation and sound insulation window unit structure and its application

Abstract

The present invention relates to a broadband ventilation and sound insulation window unit structure and its application. The broadband ventilation and sound insulation window unit structure includes an internal resonance cavity (1), a hollow tube (2), and a thin-walled outer shell (3). The outer wall of the hollow tube (2) is fixedly connected to the internal resonance cavity (1), and the outer edge of the internal resonance cavity (1) is sleeved with the thin-walled outer shell (3). The internal resonance cavity (1) includes a plurality of hollow cylinders with the same structure and size that are stacked up and down on the outer wall of the hollow tube (2). The outer edges of the bottoms of each layer of hollow cylinders are respectively provided with circumferentially structured horizontal partition plates (11). The circumferential partition partitions (4) and radial partition partitions (5) for dividing each layer of resonance cavities into multiple resonance spaces are provided on each layer of horizontal partition plates (11). Compared with the prior art, the present invention has the advantages of improving the sound insulation effect, having a wide working frequency band, being able to improve the effective sound absorption while achieving high-efficiency sound insulation, and having a wide application range, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of noise control equipment, and more particularly to a broadband ventilation sound insulation window unit structure and its application. Background Art

[0002] In acoustic engineering, simultaneously achieving sound insulation and free gas flow remains a major challenge. Sound barriers impede the transmission of airflows, while traditional ventilation barriers are generally designed with tortuous paths, which, while ensuring sufficient noise reduction, also bring about a large pressure difference, further reducing the ventilation effect. Acoustic metasurfaces, an increasingly well - studied field, have demonstrated their unparalleled ability to modulate acoustic wave interactions and have provided unprecedented opportunities for researchers in acoustic field manipulation at deep sub - wavelength levels, such as sub - wavelength focusing / imaging, unidirectional sound transmission, anomalous refraction and reflection, and compact absorbers. Due to their superiority in sub - wavelength acoustic field manipulation, acoustic metasurfaces offer an effective way to design breathable sound barriers, resulting in a perforated design composed of periodically arranged hollow units to ensure sufficient air circulation. By utilizing locally resonant units (Helmholtz resonators, membranes, quarter - wavelength tubes, etc.) or Fano - like resonances, the limitations of modulating large - scale waves in the sub - wavelength range have been overcome, and sound obstruction has been achieved. Nevertheless, the underlying working mechanisms enable them to provide a narrow operating bandwidth only near the resonant or destructive interference frequencies. Recent studies have shown that broadband absorption at low frequencies can be achieved by coupling multiple lossy resonators in ventilation barriers. In addition, barriers made of hollow spiral units can provide Fano - like interference in specific frequency bands, thus achieving broadband sound insulation in the mid - to high - frequency range. Although these designs have made significant progress in dealing with broadband problems, the bandwidth is still limited. If evaluated by the range that blocks more than 90% of the incident energy, the sound insulation bandwidth is usually less than one octave. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above - mentioned defects existing in the prior art and provide a broadband ventilation sound insulation window unit structure and its application.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A broadband ventilation sound insulation window unit structure includes an internal resonance cavity, a hollow tube, and a thin - walled outer shell. The outer wall of the hollow tube is fixedly connected to the internal resonance cavity, and the outer edge of the internal resonance cavity is sleeved with a thin - walled outer shell. The internal resonance cavity includes multiple layers of hollow cylinders with the same structure and size that are stacked up and down on the outer wall of the hollow tube. The outer edges of the bottoms of each layer of hollow cylinders are respectively provided with circumferentially structured horizontal partition plates. The circumferential partition plates and radial partition plates for dividing each layer of the resonance cavity into multiple resonance spaces are provided on each layer of the horizontal partition plates.

[0006] The internal resonant cavity includes eight hollow cylinders stacked up and down on the outer wall of the hollow tube. Horizontal partition plates with a circumferential structure are respectively provided at the outer edges of the bottoms of each layer of hollow cylinders, and the sizes and structures of the horizontal partition plates of each layer are the same.

[0007] On each layer of the horizontal partition plates, four circumferential partition partitions with different lengths and non-closed circumferential structures are respectively provided, and the circumferential partition partitions are equally spaced around the center of the hollow tube. The opening areas and opening positions at the non-closed openings of the circumferential partition partitions provided on each layer of the horizontal partition plates are the same. Radial partition partitions are respectively provided between adjacent circumferential partition partitions on each layer of the horizontal partition plates, and radial partition partitions are provided on the outer walls of the outermost circumferential partition partitions. All the radial partition partitions are on the same horizontal line.

[0008] On each layer of the horizontal partition plates, a radial partition partition is provided at the non-closed opening of the circumferential partition partition, and the non-closed opening of the circumferential partition partition is evenly divided into two cavity openings with the same opening area by the radial partition partition.

[0009] Further, the hollow tube is a rigid cylindrical hollow tube, and the thin-walled outer shell is an annular outer shell.

[0010] The second object of the present invention is to propose a broadband sound barrier, which includes a plurality of the broadband ventilation and sound insulation window unit structures evenly spliced in a basic manner.

[0011] Further, the broadband sound barrier includes a plurality of square frames evenly spliced in a basic manner. The broadband ventilation and sound insulation window unit structure is embedded in each square frame, and the broadband ventilation and sound insulation window unit structure is in transitional fit with the square frame.

[0012] Further, the broadband sound barrier includes a plurality of solid cubes with the same size of 1 / 4 cylinders cut off at the four corners and evenly spliced in a basic manner. The broadband ventilation and sound insulation window unit structure is embedded in each solid cube, and the broadband ventilation and sound insulation window unit structure is in transitional fit with the solid cube.

[0013] The broadband ventilation and sound insulation window unit structure and its application provided by the present invention have at least the following beneficial effects compared with the prior art:

[0014] 1) The broadband ventilation and sound insulation window unit structure based on the synergistic effect of loss and interference is provided with a hollow ventilation aperture. The purpose of the hollow tube design is to leave a direct air circulation path. Traditional ventilation and sound insulation windows usually consist of sound-absorbing materials or sound-absorbing structures laid in tortuous ventilation ducts, which increases the flow resistance and has a much worse ventilation effect than a direct ventilation path. The design of the present invention can prove that it can break through the limitation of the narrow working frequency range through the analysis of structural energy loss and interference, and is also applicable to obliquely incident sound waves at different angles, greatly improving the application range of the broadband ventilation and sound insulation window unit structure based on the synergistic effect of loss and interference;

[0015] 2) By using the circumferential partition plates of each layer and the radially partition plates with gradually changing angles of each layer, the overall structure is divided into 64 carefully designed resonant cavities. Through the coherent coupling of the cavities, high-efficiency sound insulation can be achieved based on the synergistic effect of the loss and interference of the structure, and at the same time, effective sound absorption is realized;

[0016] 3) The structure of the present invention is simple. By adjusting the angle of the radially partitioned plates, the structure can achieve high-efficiency energy loss and interference in the corresponding frequency band to achieve the broadband sound insulation effect in a specific frequency band. It can be confirmed that a sample with a thickness of 5.3 cm (~λ / 10) can effectively isolate 90% of the incident sound wave energy from all directions in the frequency band range of 650 Hz - 2000 Hz;

[0017] 4) In the present invention, a radially partitioned plate is provided at the non-closed opening of the circumferential partition plate on each layer of the horizontal partition plate. The radially partitioned plate divides the non-closed opening of the circumferential partition plate into two cavity openings with the same opening area. Setting the cavity openings can connect the ventilation channel with the internal cavity, enabling sound waves to enter the cavity to generate resonance, and the adjacent openings of each layer can enable the cavities corresponding to each cavity opening to interact with each other. Description of the Drawings

[0018] Figure 1 Schematic diagram of the external structure of the broadband ventilation and sound insulation window unit structure in the embodiment;

[0019] Figure 2 Schematic diagram of the internal structure of the broadband ventilation and sound insulation window unit structure in the embodiment;

[0020] Figure 3 Schematic diagram of the loss and interference principle curve of the broadband ventilation and sound insulation window unit structure in the embodiment;

[0021] Figure 4 Schematic diagram of the energy transmission curve of the broadband ventilation and sound insulation window unit structure in the embodiment;

[0022] Figure 5 Experimental test energy transmission curve diagram of the broadband ventilation and sound insulation window unit structure in the embodiment;

[0023] Figure 6 The energy transmission coefficient curves of the broadband ventilation and sound insulation window unit structures with the incident angles of sound waves being 0°, 30°, and 60° in the embodiments;

[0024] Figure 7 The structural schematic diagram of the combined sound barrier designed with the broadband ventilation and sound insulation window unit structure as the basic unit in the embodiments;

[0025] Figure 8 The structural schematic diagram of another combined sound barrier composed of the broadband ventilation and sound insulation window unit structure of the present invention in the embodiments;

[0026] As indicated by the reference numerals in the figure:

[0027] 1. Internal resonance cavity, 2. Hollow tube, 3. Thin-walled outer shell, 4. Circumferential partition partition, 5. Radial partition partition, 6. Cavity opening, 7. Broadband ventilation and sound insulation window unit structure, 8. Square frame, 9. Ventilation area, 10. Solid wall, 11. Horizontal partition board. Specific embodiments

[0028] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0029] Embodiment

[0030] The present invention provides a broadband ventilation and sound insulation window unit structure, which is realized based on the synergistic effect of loss and interference, as Figure 1 、 Figure 2 shown. This structure includes an internal resonance cavity 1, a hollow tube 2, and a thin-walled outer shell 3. The hollow tube 2 is a rigid cylindrical hollow tube. The outer wall of the hollow tube 2 is fixedly connected to the internal resonance cavity 1, and the outer edge of the internal resonance cavity 1 is sleeved with the thin-walled outer shell 3, and the thin-walled outer shell 3 is an annular outer shell.

[0031] The internal resonance cavity 1 includes eight hollow cylinders stacked up and down on the outer wall of the hollow tube 2. The sizes and shapes of the hollow cylinders are the same, Figure 2 where d in Figure 1 is the inner diameter of the hollow cylinder. The bottom outer edges of the hollow cylinders in each layer are respectively provided with horizontal partition boards 11 with a circumferential structure, and the sizes and structures of the horizontal partition boards 11 in each layer are the same. The horizontal partition board 11 first divides the internal resonance cavity 1 into 8 layers of resonance cavities.

[0032] On each layer of the horizontal partition plate 11, 4 circumferential partition partitions 4 with circumferentially non-closed structures are equally spaced. The lengths of adjacent circumferential partition partitions 4 are different, but they are centered on the hollow tube 2, and the intervals between adjacent circumferential partition partitions 4 are equal, that is, the 4 circumferential partition partitions 4 divide each layer of the resonant cavity at equal intervals. The non-closed part is an opening, and the opening positions, angles, and sizes of each circumferential partition partition 4 are the same, that is, each layer of the resonant cavity has the same opening area. In order to use coherent coupling to solve the broadband problem, the openings of the resonant cavities are adjacent to each other (the opening area of each layer of the resonant cavity is S n ).

[0033] Between adjacent circumferential partition partitions 4 of each layer, radial partition partitions 5 are respectively provided. The outer wall of the outermost circumferential partition partition 4 is also provided with a radial partition partition 5. Each radial partition partition 5 of each layer is located on the same horizontal line. That is, each layer divides the space formed by the circumferential partition partitions 4 into 8 spaces by setting 4 radial partition partitions 5; then a total of 64 resonant cavities are formed by 8 layers of resonant cavities. The included angles of the radial partition partitions 5 of the internal resonant cavities of each layer gradually change in a gradient manner.

[0034] Furthermore, an additional radial partition partition 5 is provided at the opening of the circumferential partition partition 4 on each layer of the horizontal partition plate 11. This radial partition partition 5 divides the opening of the circumferential partition partition 4 into two equal parts, so that the overall structure has a total of 16 cavity openings 6, and the opening areas of each cavity opening 6 are the same. The purpose of setting the cavity opening 6 in the present invention is to connect the ventilation channel and the internal cavity, so that sound waves enter the cavity to generate resonance. The openings are adjacent to each other so that the cavities corresponding to each opening interact with each other.

[0035] In summary, the geometric shapes of the eight-layer resonant cavities are the same. Except for the gradually offset angles (the thickness t of the radial partition partition 5) of the radial partition partitions 5 (the first-layer separation angle ψ, and the angle offset θ of each layer), the entire structure is actually composed of 64 resonant cavities. These resonant cavities are clearly conceived, so each resonant cavity has its own function (high-efficiency loss or interference), and they jointly provide excellent sound insulation effect in a large frequency range.

[0036] Based on the above structural design, for the broadband ventilation and sound insulation window unit structure based on the synergistic effect of loss and interference, its acoustic performance can be characterized by its transfer matrix T0, which associates the state vectors of the sound fields at the input and output parts of the cross-element unit, and the following can be obtained represents the sound pressure and velocity at the input end, T0 is the transfer matrix, is the sound pressure and velocity at the output end.

[0037] Note that the overall performance of the unit is determined by the cross-sectional mutations at the input and output interfaces and the 64 side-branch resonators. Since the unit has a sub-wavelength thickness, the spacing between these cavities is in the deep sub-wavelength range, and it can be further assumed that all these resonators share the same position in the middle of the unit. Therefore, the transfer matrix T0 can be written as T0 = T f T a T r . Theoretically, the structure is equivalent to a stepped cross-section tube with all resonators installed at the bisecting plane. The matrix T f / describes the contribution of the cross-sectional mutation of the first half or the second half of the stepped cross-section tube, where T f represents the contribution of the cross-sectional mutation of the first half of the stepped cross-section tube, and T r represents the contribution of the cross-sectional mutation of the second half of the stepped cross-section tube:

[0038]

[0039] In the formula: k0 is the wave number of the sound wave in the air, φ0 represents the opening area of the unit, and L c =(0.5×H + ΔH) is the effective length of the first half or the second half of the stepped cross-section tube considering the end correction. Here, the end correction can be set to The matrix Ta represents the contribution from the 64 side-branch resonators. Such closely arranged resonators have a strong coherent coupling effect, resulting in that all the resonator cavities can be regarded as an overall coupled system, and its acoustic impedance can be calculated as follows.

[0040] First, by replacing all other resonators with hard walls, the acoustic impedance of each resonator can be defined with reference to the entire coupled system. In this way, the impedance of the acoustic impedance of the resonator in the overall coupled system can be expressed as Z n =-jρ c c c cotk c L n / (ξρc). Where k c , ρ c and c c are the wave number, air density and sound speed in the resonator respectively. Considering the inherent losses caused by the viscous and thermal boundary layers in these narrow cavities, these parameters (k c , ρ c , c c ) now become complex numbers. L n is the effective length of the nth resonator, and ξ is the ratio of the cross-sectional area of the resonator to its opening area. ρc is the air impedance, -j is the negative imaginary operator, and cot is the cotangent trigonometric function symbol. Then, the total acoustic impedance of these 64 resonators can be obtained:

[0041]

[0042] Equation (2) gives the impedance of 64 resonators with coherent coupling. By further considering the cross-sectional area of the abrupt cross-section tube S and the total opening area S of all resonator assemblies a , it can be obtained that:

[0043]

[0044] Based on equations (1) and (3), the transfer matrix T0 of the designed meta-unit is finally obtained. Then, the sound transmission coefficient T of the meta-unit can be directly predicted by the following formula:

[0045] T = (2 / |t 11 + t 12 + t 21 + t 22 |) (4)

[0046] where t ij (i, j = 1, 2) are the elements of the transfer matrix T0.

[0047] The present invention realizes high-efficiency sound insulation based on the synergistic effect of loss and interference. By using the circumferential partition plates of each layer and the normal partition plates with gradually changing angles of each layer, the overall structure is divided into 64 carefully designed resonant cavities. Through the coherent coupling of the cavities, high-efficiency sound isolation is achieved based on the synergistic effect of the loss and interference of the structure, and at the same time, effective sound absorption is realized. The absorption coefficient of the unit is greater than 0.5 at 450 - 580 Hz, and interference plays a major role after 600 Hz. Under the synergistic effect of loss and interference, the unit finally forms an acoustic performance of blocking more than 90% of the incident sound energy in the range of 650 - 2000 Hz, that is, 10 dB in the transmission loss TL.

[0048] To verify the effectiveness of the structure of the present invention in isolating sound energy, simulations were carried out in this embodiment. Table 1 shows the structural parameters in the calculation and simulation.

[0049] Table 1 Structural parameters in the calculation and simulation

[0050] D d h b H ψ θ <![CDATA[S n > t 100 mm 44 mm 5.5 mm 1 mm 53 mm 120° 8° <![CDATA[42.3mm 2 > 1 mm

[0051] In addition to theoretical calculations and simulations, experiments were also carried out in this embodiment to verify the effectiveness of the structure of the present invention. In this embodiment, the Sinus-type impedance tube was used to measure by the double-load method. The test sample was 3D printed using a photosensitive resin material. The test principle was to measure the sound pressure transmission coefficient by the transfer matrix method, and on this basis, the energy transmission coefficient was calculated. This experiment was carried out under the conditions that the incident angles of the sound wave were 0°, 30°, and 60° respectively, as Figure 6As shown. It can be seen from the experimental data that more than 90% of the acoustic energy can be isolated in the frequency range of 650 - 2000 Hz. Compared with the traditional local resonance unit, this broadband structure design expands its applicable range.

[0052] In addition, in practical applications, the sound barrier is not limited to vertical incidence. In fact, the acoustic metasurface composed of sub - wavelength units means that the acoustic particles in the metamaterial unit are restricted in one - dimensional motion along the center, and the incident angle can be ignored. In Figure 7 , the present invention also uses the simulation calculation method to study the transmission coefficient of the sound barrier at different oblique incident angles. In the case of oblique incidence at a certain angle, this structure still has broadband sound insulation characteristics, and even the sound insulation effect of oblique incidence is better in terms of the overall sound insulation effect.

[0053] The broadband ventilation and sound insulation window unit structure of the present invention can construct a relatively large - volume ventilation and sound insulation barrier by combining and processing basic units, and can be applied to green buildings. When applied to a broadband ventilation sound barrier, the arrangement method is that multiple ventilation and sound insulation window units are in a basic splicing manner. Figure 7 、 8 Two splicing examples are shown as follows. Figure 7 is to embed the broadband ventilation and sound insulation window unit structure 7 into the square frame 8 and then arrange them. The broadband ventilation and sound insulation window unit structure 7 is in transitional fit with the square frame 8. After splicing, the ventilation area is the hollow in the center of each broadband ventilation and sound insulation window unit structure 7 plus the extra area at the four corners. Figure 8 is to embed the broadband ventilation and sound insulation window unit structure 7 into a solid wall 10. The solid wall 10 is a cube structure, and then 1 / 4 of a cylinder with the same size is cut off from each corner of the solid wall 10 and then spliced. The ventilation area of this structure is the hollow in the center of each broadband ventilation and sound insulation window unit structure 7 plus the hollow of the cylinder formed after combination. When the broadband ventilation and sound insulation window unit structure of the present invention is applied to a broadband ventilation sound barrier through basic splicing, there can be various arrangement forms. Figure 7 、 Figure 8 The two splicing methods shown are the preferred implementation schemes of the present invention and do not represent the only implementation method.

[0054] The above - mentioned are only the specific implementation manners of the present invention, but the protection scope of the present invention is not limited thereto. Any staff familiar with the technical field of the present invention can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A broadband ventilation and sound insulation window unit structure, characterized in that It includes an internal resonator (1), a hollow tube (2) and a thin-walled outer shell (3). The outer wall of the hollow tube (2) is fixedly connected to the internal resonator (1), and the outer edge of the internal resonator (1) is sleeved with the thin-walled outer shell (3). Circumferential partition partitions (4) and radial partition partitions (5) for dividing each layer of the resonator into a plurality of resonant spaces are provided on each layer of horizontal partition plates (11). The internal resonator (1) includes eight hollow cylinders stacked up and down on the outer wall of the hollow tube (2). The sizes and shapes of the hollow cylinders are the same. Horizontal partition plates (11) with circumferential structures are respectively provided at the outer edges of the bottoms of each layer of hollow cylinders, and the sizes and structures of each layer of horizontal partition plates (11) are the same. The opening areas and opening positions at the non-closed openings of the circumferential partition partitions (4) provided on each layer of horizontal partition plates (11) are the same. The hollow tube (2) is a rigid cylindrical hollow tube, and the thin-walled outer shell (3) is an annular outer shell. Four circumferential partition partitions (4) with different lengths and circumferential non-closed structures are respectively provided on each layer of horizontal partition plates (11), and the circumferential partition partitions (4) are equally spaced around the center of the hollow tube (2).

2. The broadband ventilation and sound insulation window unit structure according to claim 1, wherein, Radial partition partitions (5) are respectively provided between adjacent circumferential partition partitions (4) on each layer of horizontal partition plates (11). Radial partition partitions (5) are provided on the outer walls of the outermost circumferential partition partitions (4). All the radial partition partitions (5) are on the same horizontal line.

3. The broadband ventilation and sound insulation window unit structure according to claim 2, characterized in that, One radial partition partition (5) is provided at the non-closed opening of the circumferential partition partition (4) on each layer of horizontal partition plates (11), and the radial partition partition (5) divides the non-closed opening of the circumferential partition partition (4) into two cavity openings (6) with the same opening area.

4. A broadband sound barrier applying the broadband ventilation and sound insulation window unit structure as described in claim 3, characterized in that, It includes a plurality of the broadband ventilation and sound insulation window unit structures spliced evenly in a basic manner.

5. The broadband sound barrier according to claim 4, characterized in that, The broadband sound barrier includes a plurality of square frames spliced evenly in a basic manner. The broadband ventilation and sound insulation window unit structure is embedded in each square frame, and the broadband ventilation and sound insulation window unit structure is in transitional fit with the square frame.

6. The broadband sound barrier according to claim 4, wherein, The broadband sound barrier includes a plurality of solid cubes with the same size of 1 / 4 cylinders cut off at the four corners spliced evenly in a basic manner. The broadband ventilation and sound insulation window unit structure is embedded in each solid cube, and the broadband ventilation and sound insulation window unit structure is in transitional fit with the solid cube.

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