Ventilation-sound insulation integrated ultrathin metasurface grating and use method

Abstract

The invention discloses a ventilation-sound insulation integrated ultrathin metasurface grating and a using method thereof. The grating is composed of a perforated cover plate, a bottom plate, a plurality of slender cavities with different lengths formed by separating the perforated cover plate and the bottom plate through wall plates, and a peripheral grid-shaped ventilation area. According to the grille, the excellent broadband sound insulation performance can be achieved on the premise that the high ventilation quantity is guaranteed through a thin layer structure with the thickness as low as about 20 mm. The folded labyrinth resonance sound absorption units with gradient lengths are arranged in the non-ventilation area, broadband continuous sound absorption peaks can be generated, and sound absorption replaces sound insulation, so that broadband sound attenuation performance is obtained. Compared with an existing ventilation and sound insulation grille, the grille structure is thinner, larger in ventilation area and wider in working frequency band, the wide engineering application value of the grille structure is shown, a light-weight and low-frequency broadband noise reduction solution is provided for mechanical equipment such as airplanes, warships, high-speed rails and automobiles, and the mechanical equipment can be widely applied to mechanical equipment such as the airplanes, the warships, the high-speed rails and the automobiles. And the method also has wide application prospects in ventilation and sound insulation systems in green buildings.

Description

Technical Field

[0001] The present invention belongs to the technical field of ventilation and noise reduction, and in particular relates to an ultra-thin ultra-surface grille integrating ventilation and sound insulation and a method for using the grille. Background Art

[0002] Acoustic superstructures have been a hot topic in the field of acoustics since the 21st century, providing a new way to achieve ventilation and noise reduction technology. Specifically, the propagation and behavior of sound waves can be controlled and manipulated by designing the physical parameters of subwavelength structures, showing unique properties that traditional materials do not have. At present, some structures based on acoustic superstructures have been proposed to solve the challenge of sound attenuation while maintaining air channels.

[0003] In summary, there are some common acoustic superstructure design methods for ventilated sound insulation structures, which can take into account both sound insulation and ventilation performance. However, they still have some disadvantages. The tension of the membrane superstructure is not easy to control accurately, which may affect the performance and stability of the structure. The local resonance type and Fano interference type superstructures have a narrow anechoic band and insufficient performance in low frequencies. In addition, some superstructures are thick and have low ventilation rates, which will increase the weight and volume of the structure and limit its effect in actual ventilation applications. Therefore, it is still a challenge to design a thin and light ventilated sound insulation acoustic superstructure that meets the low-frequency broadband, high ventilation and high sound insulation performance, while taking into account the concept of environmental friendliness and green building. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of existing ventilation and noise reduction technologies, and to provide a ventilation-sound insulation integrated ultra-thin ultra-surface grille and a use method for realizing small space applications with integrated ventilation and sound insulation under low-frequency and broadband conditions.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: A ventilation-sound insulation integrated ultra-thin ultra-surface grille, the grille is composed of folded resonant sound-absorbing units of different lengths arranged in a maze-like manner in a plane, and is surrounded by a grid-like ventilation area; The sound absorbing unit includes a perforated cover plate and a bottom plate separated by a wall plate to form a plurality of elongated cavities of different lengths. A through hole is provided at the front end of each elongated cavity on the perforated cover plate. According to the size of the installation space in actual applications, when in use, the sound absorbing unit with the elongated cavity is arranged in a compact space by folding or curling. The ventilation area is located around the sound absorbing unit. A lattice-shaped hollow area with the same area ratio is provided at the same position of the perforated cover plate, the bottom plate and the intermediate frame wall plate.

[0006] A further improvement of the present invention is that the grille uses a plurality of Helmholtz resonance cavity sound absorbing units in a labyrinth arrangement and combination, and is combined with a lattice-shaped ventilation area, thereby achieving high ventilation performance and excellent sound insulation performance.

[0007] A further improvement of the present invention is that the thickness of the labyrinth-type ventilation and sound insulation structure is 10-30 mm.

[0008] A further improvement of the present invention is that the labyrinth-type ventilation sound insulation structure arranges and combines the single Helmholtz resonance cavity sound absorbing units with narrow working frequency bands in a coherent relationship, so that the structure works in a wider frequency band.

[0009] A further improvement of the present invention is that the working frequency band is moved to a higher or lower frequency region by increasing the number of Helmholtz resonance cavities and adjusting the width of their open channels.

[0010] A further improvement of the present invention is that a plurality of sound absorbing units are connected end to end and alternately coiled to form a maze-like structure, and sound waves are reflected and scattered multiple times inside the units, increasing the time and probability of the sound waves contacting the sound absorbing structure and improving the sound absorption effect.

[0011] A further improvement of the present invention is that the sound absorbing unit has a set sound absorbing radius, and the size of the sound absorbing radius is sufficient to cover the ventilation area.

[0012] A further improvement of the present invention is that the perforated cover plate, the bottom plate and the wall plate are all made of plastic or resin.

[0013] A further improvement of the present invention is that the diameter of the through hole is 1.5-3.4 mm.

[0014] A method for using a ventilation-sound insulation integrated ultra-thin ultra-surface grille, comprising: 1) According to the noise reduction frequency band and the layout space size conditions, determine the cross-sectional width, channel length, and neck aperture size of the slender cavity. In the low-frequency band, the cross-sectional width is small, the channel is long, and the single-hole aperture is small. In the high-frequency band, the cross-sectional width is large, the channel is short, and the double-hole aperture is large; 2) According to the bandwidth of the required anechoic frequency band and the allowed space size, the frequency band is divided into multiple sub-bands, and different elongated cavity lengths are selected so that the sound absorption peak frequency of each elongated cavity sound absorption unit matches the center frequency of each sub-band; 3) According to the required ventilation needs, the ventilation area ratio is determined, and the ventilation area and the sound absorption area formed by the space folding or curling of each slender cavity sound absorption unit are compactly arranged in a given installation space to achieve broadband ventilation and noise reduction.

[0015] Compared with the prior art, the present invention has at least the following beneficial technical effects: 1. The ventilation and sound insulation grille has an ultra-thin structure with a thickness of only 10-30mm and has the advantage of deep sub-wavelength; 2. Due to the principle of acoustic siphon effect, the sound absorption unit has a set sound absorption radius, and the sound absorption range effectively covers the ventilation area. The ventilation area ratio can be as high as 55%, which effectively absorbs sound while providing high ventilation; 3. Through the parallel synergistic coupling between multiple sound-absorbing units with different gradient coefficient lengths and the coherent mutual coupling between units, the amplitude of some single sound absorption peaks can be increased. The sound absorption peaks at different resonance frequencies generated by multiple sound-absorbing units are coupled to generate sound absorption peaks at additional resonance frequencies. Therefore, a broadband silencing effect with a bandwidth of nearly one octave can be obtained in the low- and medium-frequency bands of 300-800Hz and the high- and medium-frequency bands of 900-2000Hz. 4. By adjusting the aperture d, hole depth h, cavity depth H, and cavity length L of the sound absorbing unit as a whole, the frequency band of the labyrinth-type ventilation and sound insulation structure is shifted to different working frequency ranges, so as to design ventilation and sound insulation integrated grilles for different low, medium, and high frequency bands according to needs; 5. When the ventilation area ratio is 25%, the structure S2 designed for medium and low frequencies shall achieve an average sound insulation of at least 3.12dB in the wide frequency range of 330-800Hz, and the structure S1 designed for medium and high frequencies shall achieve an average sound insulation of at least 10.36dB in the wide frequency range of 900Hz-2000Hz. The thickness of the former is only 1 / 23 of the wavelength, and the thickness of the latter is only 1 / 8 of the wavelength.

[0016] In summary, the present invention provides an ultra-thin ultra-surface grille with integrated ventilation and sound insulation, which achieves excellent broadband sound insulation performance and ensures high ventilation efficiency while maintaining a thickness as low as about 20 mm. A folded labyrinth resonance sound absorption unit with a gradient length is set in the non-ventilated area of ​​the grille to produce a broadband continuous absorption peak. Through the design concept of replacing isolation with absorption, the grille achieves excellent broadband low-frequency noise attenuation. Since the sound absorption unit has a set sound absorption radius, its size can cover the ventilation area around it. The sound absorption unit gathers and concentrates the surrounding sound energy through the neck and dissipates it by overcoming resistance friction. Therefore, the ventilation grille can overcome the sound leakage problem caused by strong sound wave diffraction, and effectively isolate the sound while maintaining ventilation. The grille structure has the characteristics of thinner thickness, larger ventilation area, wider working frequency band, etc., and has a wide range of engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of a labyrinth-type integrated ultra-thin grille for ventilation and sound insulation; Figure 2 Schematic diagram of ventilation sound insulation structure S1 designed for medium and low frequency bands; Figure 3The calculation results of the sound transmission loss of the ventilation sound insulation structure S1 designed for the medium and low frequency bands; Figure 4 The calculation results of sound transmission loss and bandwidth of structure S1 under different ventilation area ratios α; Figure 5 The calculation results of sound transmission loss of structure S1 under different apertures d; Figure 6 The calculation results of sound transmission loss and bandwidth of structure S1 under different perforated cover plate thickness h; Figure 7 Schematic diagram of ventilation sound insulation structure S2 designed for mid-high frequency bands; Figure 8 The calculation results of the sound transmission loss of the ventilation sound insulation structure S2 designed for the mid- and high-frequency bands; Fig. 9 The calculation results of sound transmission loss of structure S2 under different frame thickness H; Fig.10 (a) and (b) are schematic diagrams of samples with different ventilation area ratios α and different apertures d for the medium and low frequency structure S1; Fig.11 Comparison between simulation and experimental calculation results of sound transmission loss of structure S2 with ventilation area ratio α=15%; Fig.12 Comparison between simulation and experimental calculation results of sound transmission loss of structure S1 with perforated cover plate thickness h=1 mm; Fig.13 Experimental device for testing ventilation performance; Fig.14 (a) and (b) are the experimental results of wind speed ratio and air volume ratio with and without samples passing through; Fig.15 (a) and (b) are the experimental results of wind speed and air volume loss ratio with and without samples passing through.

[0018] Description of reference numerals: 1- elongated cavity; 2- through hole; 3- wall plate; 4- perforated cover plate; 5- bottom plate. DETAILED DESCRIPTION

[0019] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0020] 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 orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0024] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0025] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0026] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0027] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0028] Example 1 The present invention provides a ventilation-sound insulation integrated ultra-thin ultra-surface grille, which is composed of folded resonant sound-absorbing units of different lengths arranged in a maze-like manner in a plane, and is surrounded by a grid-like ventilation area; the sound-absorbing unit includes a perforated cover plate 4 and a bottom plate 5 separated by a wall plate 3 to form a plurality of elongated cavities 1 of different lengths, and a through hole 2 is opened on the perforated cover plate 4 at the front end of each elongated cavity 1. According to the size of the installation space in actual applications, when in use, the sound-absorbing units with the elongated cavities 1 are arranged in a compact space by folding or curling, the ventilation area is located around the sound-absorbing unit, and a grid-like hollow area with the same area ratio is formed at the same position of the perforated cover plate 4, the bottom plate 5 and the middle frame wall plate 3.

[0029] In this embodiment, the grille is designed with the innovative concept of absorption instead of isolation, and uses multiple Helmholtz resonance cavity sound absorption units to arrange and combine in a maze-like manner, while combining with a lattice-shaped ventilation area to achieve high ventilation performance while achieving excellent sound insulation performance.

[0030] In this embodiment, the thickness of the labyrinth-type ventilation and sound insulation structure is 10-30 mm, which greatly reduces the thickness required for low-frequency sound absorption and realizes an ultra-thin design, which is suitable for application scenarios in smaller spaces.

[0031] In this embodiment, the labyrinth-type ventilation sound insulation structure introduces a phase coupling method, and the structure works in a wider frequency band by arranging and combining the single Helmholtz resonance cavity sound absorption units with a narrow working frequency band in a coherent relationship.

[0032] In this embodiment, the working frequency band is moved to a higher or lower frequency region by increasing the number of Helmholtz resonance cavities and adjusting the width of their open channels.

[0033] In this embodiment, a plurality of sound absorbing units are connected end to end and alternately coiled to form a maze-like structure. Sound waves are reflected and scattered multiple times inside the units, effectively increasing the time and probability of contact between the sound waves and the sound absorbing structure, thereby improving the sound absorption effect.

[0034] In this embodiment, the sound absorbing unit has a set sound absorbing radius, and the size of the sound absorbing radius is sufficient to cover the ventilation area, thereby overcoming the sound leakage problem caused by strong diffraction of sound waves and realizing the organic combination of ventilation and sound insulation.

[0035] In this embodiment, the perforated cover plate 4, the bottom plate 5 and the wall plate 3 are all made of plastic or resin, and the materials are highly replaceable.

[0036] In this embodiment, the diameter of the through hole 2 is 1.5-3.4 mm.

[0037] Example 2 The present invention provides a method for using a ventilation-sound insulation integrated ultra-thin ultra-surface grille, comprising: 1) According to the noise reduction frequency band and the layout space size conditions, determine the cross-sectional width, channel length, and neck aperture size of the slender cavity. In the low-frequency band, the cross-sectional width is small, the channel is long, and the single-hole aperture is small. In the high-frequency band, the cross-sectional width is large, the channel is short, and the double-hole aperture is large; 2) According to the bandwidth of the required anechoic frequency band and the allowed space size, the frequency band is divided into multiple sub-bands, and different elongated cavity lengths are selected so that the sound absorption peak frequency of each elongated cavity sound absorption unit matches the center frequency of each sub-band; 3) According to the required ventilation needs, the ventilation area ratio is determined, and the ventilation area and the sound absorption area formed by the space folding or curling of each slender cavity sound absorption unit are compactly arranged in a given installation space to achieve broadband ventilation and noise reduction.

[0038] Example 3 like Figure 1 As shown, the present invention provides a ventilation-sound insulation integrated ultra-thin super-surface grille, which consists of three layers: a perforated cover plate 4, a bottom plate 5, and a plurality of elongated cavities 1 of different lengths are separated by a wall plate 3 between the perforated cover plate 4 and the sealed bottom plate 5. A through hole 2 is provided at the front end of each elongated cavity 1 on the perforated cover plate 4. Each layer contains ventilation areas of the same position and area. The structure utilizes the Helmholtz resonance cavity principle to generate loss in sound transmission and achieve high sound insulation performance. At the same time, ventilation is performed between the structures through the lattice-shaped ventilation area.

[0039] 1. Design and parameter influence of the integrated labyrinth-type ultra-thin structure S1 for medium and low frequency ventilation and sound insulation As an implementation example, Figure 1As shown in the figure, a structure is designed, which is a ventilation sound insulation structure S1 for medium and low frequency noise to meet the noise attenuation requirements of the medium and low frequency bands. Specifically, the slender cavity L of S1 is 5 mm, the single hole has a hole diameter d of 2.2 mm, the perforated cover plate thickness h is 1 mm, the wall plate frame thickness H is 28 mm, and the bottom plate thickness is 1 mm. Figure 2 As shown in the figure, the structural area is 100 mm × 100 mm, the ventilation area ratio α is 25%, and it consists of 11 Helmholtz resonance sound absorption cavities. The thickness of the partition wall between the cavities is 1 mm, the thickness of the partition wall of the outer lattice ventilation area is 1.2 mm, and the cavity depth is 28 mm. The lengths of the cavities from small to large are 33 mm, 42 mm, 51 mm, 57 mm, 69 mm, 80 mm, 85 mm, 91 mm, 127 mm, 138 mm, and 163 mm, and the distance from the center of the opening to the end is 3 mm.

[0040] The commercial multi-physics finite element analysis software COMSOL Multiphysics was used to calculate the following Figure 2 The sound transmission loss of the integrated labyrinth type ultra-thin grille for medium and low frequency ventilation and sound insulation is shown in the curve diagram as shown in Figure 3 As shown. In the calculation, the upper and lower air domains are set as pressure acoustic modules, and the part that constitutes the cavity wall is made of photosensitive resin material. The solid structure is set as a solid mechanics module, and the acoustic-structure coupling module is used to assign fixed constraints to the four boundaries of the acoustic superstructure. In order to consider the loss, the air area of ​​the structure is set as a narrow acoustic domain to simulate the sound loss, the through-hole part is set as a circular duct, and the cavity part is set as a wide tube approximation. The sound wave is incident from one side of the grille device in the form of a plane wave, enters the cavity through the through-hole, forms a Helmholtz resonator, produces resonant sound absorption, and thus reduces the transmitted sound energy. As shown Figure 3 As shown, structure S1 obtains 7 sound insulation peaks in the range of 330 Hz-800 Hz, marked as K1-K8. Due to the different cavity lengths, the sound absorption peak frequency of each sound absorption unit is different, so that the combined device produces multiple connected sound absorption peaks, achieving a wide-band sound insulation effect.

[0041] The structural parameters of the superstructure unit have a huge impact on its working frequency band range and sound insulation performance. Starting from the ventilation area ratio α, the size d of the Helmholtz resonance cavity aperture, the thickness h of the opening cover plate and other parameters, the influence of these parameters on the sound insulation characteristics and band gap characteristics of the medium and low frequency labyrinth-type ventilated sound insulation structure S1 is studied.

[0042] In order to illustrate the balance between ventilation performance and sound insulation performance of the ventilation-sound insulation integrated ultra-thin super-surface grille in the present invention, the influence of the structural parameter ventilation area ratio α on its sound insulation performance and band gap characteristics is studied. Five groups are designed for structure S1, and the structural parameters adopted are as follows: α=15%, α=25%, α=35%, α=45%, α=55%. Five groups of maze-type ventilation sound insulation units with different ventilation area ratios are designed for each. The sound insulation STL of the structure is calculated using the commercial finite element software COMSOL Multiphysics, and the superstructure sound insulation curves under different ventilation area ratios α are plotted, as well as the influence on the working bandwidth, such as Figure 4 As shown. According to the simulation results of different ventilation area ratios α, the following can be observed: It can be seen that with the increase of ventilation area, the number of sound insulation peaks decreases, and the average sound insulation in the working frequency range gradually decreases. The ventilation area ratio increases from 15% to 10% every time, the reduction rate decreases from an average of 2.84 dB to an average of 0.84 dB, and the average noise reduction decreases by 47.7%, 36.9%, 0.5%, and 42.4%, respectively. The reduction rate basically shows a trend of first decreasing and then increasing. At the same time, the lower boundary frequency of the working frequency band increases significantly, and the working bandwidth shows a trend of first increasing and then decreasing. The working bandwidth changes by about 3.26-17.17% when the ventilation area ratio increases from 15% to 10%. According to the data, the increase in the ventilation area ratio between 25-55% has little effect on the sound insulation performance, and the working bandwidth shows an overall trend of first increasing and then decreasing. Under the five ventilation area ratios and when the ventilation area ratio is as high as 55%, the working bandwidth can still exceed one octave. The sound insulation peak at low frequency is mainly determined by the outer ring, while the sound insulation peak at high frequency is determined by the inner ring cavity. Considering that the band gap characteristics of the superstructure are expected to be at a lower frequency and with a wider bandwidth, the ventilation area can be set in the inner ring part while meeting the ventilation rate requirements, while retaining the open channel with a larger volume of the outer ring cavity as a sound insulation structure.

[0043] In order to illustrate the influence of the aperture d of the ventilation-sound insulation integrated ultra-thin super-surface grille structure parameter on its sound insulation performance and band gap characteristics in the present invention, five groups of structure S1 were designed, and the structural parameters adopted were as follows: d=1.5 mm, d=2.2 mm, d=2.6 mm, d=3.0 mm, d=3.4 mm, and five groups of labyrinth-type ventilation sound insulation units with different aperture sizes were designed. The sound insulation STL of the structure was calculated using the commercial finite element software COMSOL Multiphysics, and the super-structure sound insulation curves under different apertures d were plotted, as shown in Figure 2. Figure 5As shown. According to the simulation results of different apertures d, the following can be observed: For structure S1, the analysis results show that when the aperture is 1.5mm, there are five sound insulation peaks within the working range. Due to the large damping, even if some sound insulation peaks appear, the amplitude at the resonance frequency is small compared with other frequencies. Therefore, the sound insulation peaks are not obvious at this time, and the number of sound insulation peaks is small. As the aperture d increases, the number of sound insulation peaks increases. When d = 2mm, 7 sound insulation peaks appear, and then the number of sound insulation peaks increases to 9 as d increases. For every 0.4mm increase in aperture d, the peak value of sound insulation peak increases by 0.5dB overall. In addition, as the aperture d increases, the frequency of the working bandwidth also moves to a high frequency of about 100Hz, and the working bandwidth width variation range between adjacent parameters is between 6.7-29.8%. When the diameter d doubles, the working bandwidth increases by 57.9% under the same ventilation capacity.

[0044] In order to illustrate the influence of the perforated cover plate thickness h of the ventilation-sound insulation integrated ultra-thin super-surface grille structure parameter on its sound insulation performance and band gap characteristics in the present invention, five groups were designed for structure S1, and the structural parameters adopted were as follows: h=0.5mm, h=1.0 mm, h=2.0 mm, h=3.0 mm, h=5.0 mm. Five groups of labyrinth-type ventilation and sound insulation units with different perforated cover plate thickness h were designed, as shown in the figure. The sound insulation STL of the structure was calculated using the commercial finite element software COMSOL Multiphysics, and the superstructure sound insulation curves under different perforated cover plate thickness h were drawn, as well as the influence on the working bandwidth, as shown in the figure. Figure 6 As shown. According to the simulation results of different perforated cover plate thicknesses h, the following can be observed: when the perforated cover plate thickness h is 5 mm, there are about 5 sound insulation peaks, and the difference in sound insulation at the peak and non-resonance frequency is not large. As the thickness h of the perforated cover plate decreases to 3 mm, the amplitude of the sound insulation peak decreases by about 0.3 dB on average, with basically no change, and the number of sound insulation peaks increases to 6, which is more obvious than when the thickness h=5mm, and moves to high frequency by about 30Hz. As the thickness h further decreases, the number of sound insulation peaks increases by one for each decrease in gradient, and 9 obvious sound insulation peaks appear when h=0.5nn. However, the amplitude of the sound insulation peak does not change much, but the frequency of the sound insulation peak moves to high frequency. For the working bandwidth, the results show that as the thickness h of the perforated cover plate decreases, the lower boundary of the working frequency band moves to high frequency by about 150Hz, and the upper boundary moves to low frequency by about 500 Hz. At the same time, the working bandwidth increases with the decrease in thickness h, and the variation range is between 11-24.4%. Therefore, theoretically, choosing a larger perforated cover plate thickness can satisfy a relatively lower working frequency band. The working bandwidth decreases with increasing thickness, but it still exceeds one octave under all five thicknesses.

[0045] (II) Design and parameter influence of the labyrinth-type ultra-thin structure S2 for medium and high frequency ventilation and sound insulation integration While ensuring that the structure of the original silencer remains unchanged, the width of the cavity is changed and the size of the aperture is changed on the labyrinth structure for medium and high frequency ventilation and sound insulation. A labyrinth ultra-thin structure S2 for medium and high frequency ventilation and sound insulation is obtained. The width L of the slender cavity is 8.8 mm, the double holes have a hole diameter d of 4 mm, and the thickness of the opening cover h, the frame thickness H, and the thickness of the cover remain unchanged. Figure 7 As shown in the figure, the structural area is 100 mm × 100 mm, the ventilation area ratio α is 25%, and it is composed of 20 Helmholtz resonance cavities. The thickness of the partition wall between the cavities is 1.2 mm, the thickness of the partition wall of the outer lattice ventilation area is 1.2 mm, and the cavity depth is 28 mm. The lengths of the cavities from small to large are 17.0 mm, 18.0 mm, 20.5 mm, 21.6 mm, 23.0 mm, 23.1 mm, 23.5 mm, 26.0 mm, 26.1 mm, 27.2 mm, 28.2 mm, 28.6 mm, 31.1 mm, 32.2 mm, 33.3 mm, 33.6 mm, 37.8 mm, 41.6 mm, 43.9 mm and 46.4 mm, respectively. The sound insulation simulation results of structure S2 are shown in the figure below. Figure 8 As shown in the figure, 11 clear sound insulation peaks and 10 sound insulation valleys are obtained in the range of 1000 Hz-2000 Hz. Compared with S1, the length of its resonance cavity is reduced, the length gradient is reduced, and the number of resonance cavities is increased. For the convenience of analysis, these sound insulation peaks are numbered and marked as P1 to P11. The inclination amplitude between P3 and P4, P8 and P9, and P10 and P11 is relatively small, so three clear sound insulation peaks are formed. The sound insulation peaks show an overall downward trend with the increase of frequency. It can be observed that the fluctuation degree of the sound insulation of the medium and low frequency superstructure S1 is greater than that of S2, and the peak-to-peak value of the sound insulation increases with the increase of frequency, and the average increase between each peak is 1dB.

[0046] In order to illustrate the influence of the frame thickness H of the ventilation-sound insulation integrated ultra-thin super-surface grid structure parameter on its sound insulation performance and band gap characteristics in the present invention, five groups of structure S2 were designed with the following structural parameters: H=8 mm, H=13 mm, H=18 mm, H=23 mm, H=28 mm, and five groups of labyrinth ventilation sound insulation units with different frame thicknesses H were designed. The sound insulation STL of the structure was calculated using the commercial finite element software COMSOL Multiphysics, as shown in Fig. 9As shown. According to the simulation results of different frame thicknesses H, the following can be observed: As the frame thickness H increases, the sound insulation peak amplitude does not change significantly, but the peak moves toward low frequency. The structure with a thickness of H=28 mm is reduced to a thickness of H=18 mm and H=13 mm, and the average noise reduction under the same ventilation capacity is increased by 17.9% and 23.7% respectively. The sound insulation capacity is not proportional to the thickness. On the contrary, structures with small thickness have higher average sound insulation. However, the working frequency is inversely proportional to the thickness. The thicker the structure, the lower the working frequency. As the frame thickness H increases, the upper and lower boundary frequencies of the working frequency band decrease, and the working frequency band moves toward low frequency by an average of about 150Hz. At the same time, the working bandwidth first increases and then decreases. For each gradient change, the working bandwidth varies by 7-18%.

[0047] In practical applications, the selection of structural parameters of the superstructure needs to be comprehensively considered according to actual conditions and needs. This includes considering factors such as the size of the structure, the acoustic environment, the target frequency band and the ventilation rate to design a structure with a suitable ventilation area ratio α, the diameter d of the hole and the frame thickness H, so as to obtain a superstructure with a suitable working bandwidth and excellent sound insulation performance. These simulation results and trends help to understand the changes in the sound insulation characteristics of the mid- and high-frequency labyrinth-type ventilated sound insulation superstructure unit under different ventilation area ratio conditions. Appropriate values ​​can be selected according to specific needs to achieve the best sound insulation effect in the required frequency band.

[0048] (III) Verification of ultra-thin broadband ventilation sound insulation effect In order to verify the actual sound insulation performance of the ventilation-sound insulation integrated ultra-thin super-surface grille, the following Fig.10 The sample shown is made of photosensitive resin. In order to match the impedance tube, the overall size of the structure is adjusted to 120 x 120 mm. According to GB_T32523-2016, the sound transmission loss of the sample is measured by the impedance tube test system. It can be seen that Fig.11 The experimental and simulation results of the sample with α = 15% are compared. It is obvious that the experimental and simulation results show a high degree of consistency in the entire frequency range, although the experimental results are slightly lower than the simulation results in terms of sound insulation by about 3db. The number and frequency of sound insulation peaks are basically the same. Fig.12 The experimental and simulation results of the h=1 mm sample were compared. The experimental and simulation results also showed a high degree of consistency in the entire frequency band. The number and frequency of the sound insulation peaks basically coincided, showing excellent broadband sound insulation performance.

[0049] For ventilation performance, a ventilation test was conducted on the medium and low frequency ventilation sound insulation structure S1 with a ventilation area of ​​45%. The wind speed ratio and wind volume ratio were used to measure the wind speed and wind volume passing through and not passing through the sample to indicate the ventilation performance of the sample. Fig.13As shown in the figure, the experimental device and the digital anemometer used for ventilation measurement. A 120 x 120 mm square tube was used as the air duct, and the sample was placed in the center of the tube. In the experiment, the blower placed on one side of the tube was used as the air inlet to generate airflow, and the anemometer placed on the other side measured the wind speed, which can be considered as the outlet of the airflow. At 9 different wind speeds, the average of 5 sets of data measured at each wind speed was taken as the final result. Fig.14 A comparison of the air volume and air velocity ratio with and without the sample is shown. Fig.15 The loss ratio of air volume and air speed with and without the sample is shown. The results show that the air speed and air volume with and without the sample are linearly correlated, and the air speed-air volume loss ratio is within 20%. It can be seen that with an open ventilation area of ​​45%, broadband low-frequency sound absorption can be achieved while maintaining efficient ventilation.

[0050] In summary, according to the above characteristics of a ventilation-sound insulation integrated ultra-thin super-surface grille provided by the present invention, the ventilation and sound insulation integrated ultra-thin structure provided by the present invention can not only cover the ventilation area, but also achieve effective isolation of sound waves. And the large size in the thickness direction required for low-frequency sound insulation is transferred to the ultra-thin space layer. The absorption super surface has a labyrinth-shaped curled channel, thereby greatly reducing the thickness of the structure. By arranging folded labyrinth resonant sound absorption units with gradient lengths, a broadband continuous sound absorption peak is generated, thereby obtaining broadband sound attenuation performance. The present invention aims to take into account both ventilation and sound insulation performance and meet the requirements of lightweight structure, which is of great significance for improving the environmental performance and living comfort of buildings. Compared with the existing ventilation and sound insulation grilles, the grille is thinner, has a larger ventilation area, a wider working frequency band, and has important engineering application value.

[0051] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0052] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A ventilation-sound insulation integrated ultra-thin ultra-surface grille, characterized in that: The grille is composed of folded resonant sound-absorbing units of different lengths arranged in a maze-like pattern in a plane, and is surrounded by a grid-like ventilation area; The sound absorbing unit comprises a plurality of elongated cavities (1) of different lengths separated by a wall plate (3) between a perforated cover plate (4) and a bottom plate (5), wherein a through hole (2) is provided on the perforated cover plate (4) at the front end of each elongated cavity (1). According to the size of the installation space in actual application, when in use, the sound absorbing unit having the elongated cavities (1) is arranged in a compact space by folding or curling, and the ventilation area is located around the sound absorbing unit. A lattice-shaped hollow area with the same area ratio is formed at the same position of the perforated cover plate (4), the bottom plate (5) and the intermediate frame wall plate (3).

2. The ventilation-sound insulation integrated ultra-thin ultra-surface grille according to claim 1, characterized in that: The grille uses multiple Helmholtz resonance cavity sound absorption units in a maze-like arrangement and combination, and is combined with a lattice-shaped ventilation area to achieve high ventilation performance while achieving excellent sound insulation performance.

3. The ventilation-sound insulation integrated ultra-thin ultra-surface grille according to claim 1, characterized in that: The thickness of the labyrinth type ventilation and sound insulation structure is 10-30 mm.

4. The ventilation-sound insulation integrated ultra-thin ultra-surface grille according to claim 1, characterized in that: The labyrinth-type ventilation sound insulation structure arranges and combines Helmholtz resonance cavity sound absorption units with a single narrow working frequency band in a coherent relationship, so that the structure works in a wider frequency band.

5. The ventilation-sound insulation integrated ultra-thin ultra-surface grille according to claim 1, characterized in that: By increasing the number of Helmholtz resonant cavities and adjusting the width of their open channels, the operating frequency band can be moved to a higher or lower frequency region.

6. The ventilation-sound insulation integrated ultra-thin ultra-surface grille according to claim 1, characterized in that: Multiple sound-absorbing units are connected end to end and coiled alternately to form a maze-like structure. Sound waves will be reflected and scattered multiple times inside the unit, increasing the time and probability of contact between the sound waves and the sound-absorbing structure, thereby improving the sound absorption effect.

7. The ventilation-sound insulation integrated ultra-thin ultra-surface grille according to claim 1, characterized in that: The sound absorbing unit has a set sound absorbing radius, and the size of the sound absorbing radius is sufficient to cover the ventilation area.

8. The ventilation-sound insulation integrated ultra-thin ultra-surface grille according to claim 1, characterized in that: The perforated cover plate (4), the bottom plate (5) and the wall plate (3) are all made of plastic or resin.

9. The ventilation-sound insulation integrated ultra-thin ultra-surface grille according to claim 1, characterized in that: The diameter of the through hole (2) is 1.5-3.4 mm.

10. The method for using the ventilation-sound insulation integrated ultra-thin ultra-surface grille according to claim 1, characterized in that: include: 1) According to the noise reduction frequency band and the layout space size conditions, determine the cross-sectional width, channel length, and neck aperture size of the slender cavity. In the low-frequency band, the cross-sectional width is small, the channel is long, and the single-hole aperture is small. In the high-frequency band, the cross-sectional width is large, the channel is short, and the double-hole aperture is large; 2) According to the bandwidth of the required anechoic frequency band and the allowed space size, the frequency band is divided into multiple sub-bands, and different elongated cavity lengths are selected so that the sound absorption peak frequency of each elongated cavity sound absorption unit matches the center frequency of each sub-band; 3) According to the required ventilation needs, the ventilation area ratio is determined, and the ventilation area and the sound absorption area formed by the space folding or curling of each slender cavity sound absorption unit are compactly arranged in a given installation space to achieve broadband ventilation and noise reduction.

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