A combined noise reduction and sound absorption device

Abstract

The utility model relates to noise control technical field discloses a combined formula noise reduction sound absorber, through to the sound absorber unit structure periodic arrangement combination forms the sound absorption board with larger area, installs the sound absorption board on the indoor wall or the ceiling of gas power plant workshop, realizes the indoor low frequency broadband sound absorption noise reduction, the utility model discloses a first sound absorption subassembly, including first casing and the first microperforated panel of being located at first casing, first microperforated panel is located at first casing, second sound absorption subassembly, including second casing, the second microperforated panel of being located at second casing top and the second helmholtz resonance cavity of being located at first casing below, third sound absorption subassembly, including third casing, the third microperforated panel of being located at second casing top and multiple third helmholtz resonance cavities of being located at first casing below, first sound absorption subassembly, second sound absorption subassembly, third sound absorption subassembly combination forms the sound absorption unit, and periodically arranges distribution.

Description

Technical Field

[0001] This utility model relates to the field of noise control technology, and in particular to a combined noise reduction and sound absorption device. Background Technology

[0002] With the rapid development of industry and the economy, enterprises have increasingly stringent requirements for the production environment, making noise control a crucial aspect. Inside gas-fired power plants, the operation of large equipment such as steam turbines, generators, and air compressors releases low-frequency noise. This noise has a high sound pressure level and lasts for a long time. Prolonged exposure to such an environment can damage the hearing of power plant workers, leading to occupational diseases such as tinnitus and hearing loss. It can also cause fatigue, difficulty concentrating, and other problems, increasing the risk of operational errors and seriously threatening the safe operation of the power plant.

[0003] Sound absorption treatment for factory buildings is a common and effective method for noise reduction. Sound-absorbing materials, such as porous sound-absorbing materials and micro-perforated panels, are typically installed on surfaces like walls and ceilings. These materials primarily absorb and attenuate reflected sound through their internal porous structure, reducing the reverberation field and thus lowering indoor noise. However, traditional porous sound-absorbing materials and micro-perforated panel structures have significant limitations in practical applications. For example, to achieve low-frequency broadband sound absorption, the sound-absorbing material often needs to be large in volume, occupying valuable factory space and potentially placing a significant load on the building itself, thus limiting its widespread application in engineering projects.

[0004] Micro-perforated panels are boards with tiny pores, while Helmholtz resonators consist of a sealed cavity and a circular neck that connects to the outside. Both utilize the principle of resonance to achieve sound absorption within a specific frequency range. Micro-perforated panels excel in mid-to-high frequency sound absorption, while Helmholtz resonators show significant advantages in the low-frequency range. Currently, by introducing cavity structures with different resonant frequencies in series or parallel, the sound absorption frequency range can be broadened, but the issue of a relatively large overall thickness remains. Reducing the thickness, on the other hand, leads to a narrower frequency range and poor low-frequency sound absorption.

[0005] To address the above problems, this invention proposes a combined low-frequency broadband sound absorber for noise reduction in gas-fired power plant buildings. It combines micro-perforated plates with Helmholtz resonant cavities to form a series-connected structural assembly. Furthermore, different types of micro-perforated plate units and series-connected structural assemblies are combined to form a unit structure. This allows for frequency complementarity among the components while maintaining a relatively small thickness, thereby achieving low-frequency broadband sound absorption. By periodically arranging the unit structures to form sound-absorbing panels, which are then installed on the inner walls of the power plant, noise reduction within the plant is achieved. Utility Model Content

[0006] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a combined noise-reducing sound absorber, which forms a large-area sound-absorbing panel by periodically arranging and combining sound-absorbing unit structures. The sound-absorbing panel is installed on the interior walls or ceilings of a gas-fired power plant to achieve indoor low-frequency broadband sound absorption and noise reduction.

[0007] The combined noise-reducing sound absorber according to an embodiment of the present invention includes:

[0008] The first sound-absorbing component includes a first housing and a first micro-perforated plate disposed on the first housing;

[0009] The second sound-absorbing component includes a second housing, a second micro-perforated plate disposed above the second housing, and a second Helmholtz resonant cavity disposed below the first housing;

[0010] The third sound-absorbing component includes a third housing, a third micro-perforated plate disposed above the second housing, and a plurality of third Helmholtz resonant cavities disposed below the first housing;

[0011] According to some embodiments of the present invention, the third sound-absorbing component is provided in two parts, and the first sound-absorbing component, the third sound-absorbing component, the second sound-absorbing component, and the third sound-absorbing component are combined to form a sound-absorbing unit, and multiple noise-reducing sound-absorbing units are periodically distributed.

[0012] According to some embodiments of the present invention, the first shell, the second shell, and the third shell are integrally formed or spliced ​​together.

[0013] According to some embodiments of the present invention, the inner cavity cross-section of the first sound-absorbing component, the second sound-absorbing component, and the third sound-absorbing component is circular or rectangular.

[0014] According to some embodiments of the present invention, the porosity and pore size of the first micro-perforated plate, the second micro-perforated plate, and the third micro-perforated plate are different.

[0015] According to some embodiments of the present invention, the aperture and inner cavity size of the second Helmholtz resonant cavity and the third Helmholtz resonant cavity are different.

[0016] According to some embodiments of the present invention, the cavity dimensions of the multiple third Helmholtz resonant cavities in the third sound-absorbing component are the same, but the apertures are different.

[0017] According to some embodiments of the present invention, the dimensions in the L direction of the first housing, the second housing, and the third housing are the same; the dimensions in the W direction of the first housing, the second housing, and the third housing are the same; and the dimensions in the H direction of the first housing, the second housing, and the third housing are the same.

[0018] The embodiments of this utility model have at least the following beneficial effects:

[0019] Multiple sound-absorbing structures: micro-perforated plates, a component structure formed by connecting a micro-perforated plate and a Helmholtz resonator in series, and two component structures formed by connecting a micro-perforated plate and multiple Helmholtz resonators in series. Each component structure is as follows: Figure 2 As shown;

[0020] The combined low-frequency broadband sound absorber has the advantages of smaller thickness and subwavelength scale.

[0021] By combining different types of components in parallel rather than in a single series or parallel configuration, the shortcomings in broadband sound absorption can be further compensated, resulting in a more continuous and efficient sound absorption coefficient.

[0022] The combination of the excellent high-frequency sound absorption performance of the micro-perforated plate and the good low-frequency performance of the Helmholtz resonator gives it the advantage of broadband low-frequency sound absorption.

[0023] The sound absorption performance of a single structure is determined by parameters. When a sound wave is incident perpendicularly, the sound wave of a specific frequency band causes the air in the unit structure to resonate, thereby converting the energy of that frequency band from sound energy into heat energy and dissipating it, thus completing the absorption of the sound wave of that frequency band, without absorbing the sound waves of other frequency bands.

[0024] The purpose of employing multiple sound-absorbing components is to fully utilize the coupling resonance effect between them. That is, when components with different frequency responses are combined, their respective frequency bands with resonance peaks can be effectively connected through precise design, forming a continuously covering broadband sound absorption characteristic. This synergistic effect not only improves the sound absorption coefficient but also broadens the sound absorption frequency band, enabling it to exert a good sound absorption effect over a wider frequency range. Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a combined low-frequency broadband sound absorber provided in an embodiment of the present invention;

[0026] Figure 2 This is a structural perspective view of a combined low-frequency broadband sound absorber provided in an embodiment of the present invention;

[0027] Figure 3 This is a structural cross-sectional view of a combined low-frequency broadband sound absorber provided in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the four-component structure of a combined low-frequency broadband sound absorber provided in an embodiment of the present invention;

[0029] Figure 5 This is a cross-sectional view of the component structure of a combined low-frequency broadband sound absorber, which consists of a micro-perforated plate and a Helmholtz resonant cavity, provided in an embodiment of the invention.

[0030] Figure 6 This is a cross-sectional view of the component structure of a combined low-frequency broadband sound absorber provided in an embodiment of the invention, which consists of a micro-perforated plate and two Helmholtz resonant cavities.

[0031] Figure 7 This is a simulation diagram of the sound absorption coefficient curve structure of a combined low-frequency broadband sound absorber provided in an embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of a periodically arranged sound-absorbing panel structure provided in an embodiment of the present invention;

[0033] Figure 9 This is a simulation diagram comparing the sound absorption coefficient curve structure of the present invention with that of a single element and multiple elements;

[0034] Icons: 1. Combined noise reduction and sound absorption unit; 11. First sound absorption component: micro-perforated plate structure; 12. Second sound absorption component: component structure consisting of a micro-perforated plate and a Helmholtz resonant cavity; 13, 14. Third sound absorption component: component structure consisting of a micro-perforated plate and multiple Helmholtz resonant cavities; 21. Micro-perforated plate structure; 22. Helmholtz cavity structure; 31. Micro-perforated plate structure; 32, 33. Helmholtz cavity structure; 4. Sound absorption plate. Detailed Implementation

[0035] The following will describe several embodiments of the present invention, including embodiments corresponding to the accompanying drawings. It should be understood that the drawings are used to assist in understanding the technical features and technical solutions of the present invention, and should not be construed as limiting the scope of protection of the present invention.

[0036] The following will provide a clear and complete description of the concept, specific structure, and technical effects of this utility model in conjunction with the embodiments and accompanying drawings, so as to fully understand the purpose, solution, and effects of this utility model. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0037] It should be noted that, unless otherwise explicitly defined, when a feature is referred to as "fixed," "connected," or "installed" on another feature, it can be directly fixed or connected to the other feature, or it can be indirectly fixed or connected to the other feature. The terms "fixed," "connected," and "installed" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0038] It should be noted that the descriptions of orientations or positional relationships indicated by terms such as up, down, left, right, top, bottom, front, back, inside, and outside used in this utility model are based on the orientations or positional relationships indicated by the accompanying drawings or embodiments. They are only for the purpose of facilitating the description of this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0039] It should be noted that the term "and / or" used in this utility model includes any combination of one or more of the related listed items, "several" means one or more, "multiple" means two or more, "greater than", "less than", "exceeding" are understood to exclude the number itself, and "above", "below", "within" are understood to include the number itself.

[0040] It should be noted that the use of "first" and "second" in this utility model is only for the purpose of distinguishing technical features, and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.

[0041] It should be noted that, unless otherwise expressly defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and not for limiting the scope of the invention.

[0042] Reference Figures 1-9 The basic embodiment of the first aspect of this utility model provides a combined noise-reducing sound absorber, comprising:

[0043] The first sound-absorbing component 11 includes a first housing and a first micro-perforated plate disposed on the first housing;

[0044] The second sound-absorbing component 12 includes a second housing, a second micro-perforated plate disposed above the second housing, and a second Helmholtz resonant cavity disposed below the first housing;

[0045] The third sound-absorbing component 13 includes a third housing, a third micro-perforated plate disposed above the second housing, and a plurality of third Helmholtz resonant cavities disposed below the first housing.

[0046] The first sound-absorbing component 11, the second sound-absorbing component 12, and the third sound-absorbing component 13 are arranged side by side.

[0047] The basic embodiment of the second aspect of this utility model provides a sound-absorbing panel, including multiple combined noise reduction units 1, which are periodically arranged and distributed.

[0048] According to embodiments of this utility model, by such a configuration, at least the following effects can be achieved: multiple sound-absorbing unit structures: micro-perforated plate assembly, assembly structure consisting of one micro-perforated plate and one Helmholtz resonator, and two assembly structures consisting of one micro-perforated plate and multiple Helmholtz resonator groups, each unit structure as follows... Figure 2 As shown;

[0049] The combined low-frequency broadband sound absorber has the advantages of smaller thickness and subwavelength scale.

[0050] By combining different types of units rather than simply connecting them in series or parallel, it is possible to further compensate for the shortcomings in broadband sound absorption, making it more continuous and efficient in sound absorption coefficient.

[0051] The combination of the excellent high-frequency sound absorption performance of the micro-perforated plate and the good low-frequency performance of the Helmholtz resonator gives it the advantage of low-frequency broadband sound absorption.

[0052] The sound absorption performance of a single structure is determined by parameters. When a sound wave is incident perpendicularly, the sound wave of a specific frequency band causes the air in the unit structure to resonate, thereby converting the energy of that frequency band from sound energy into heat energy and dissipating it, thus completing the absorption of the sound wave of that frequency band, without absorbing the sound waves of other frequency bands.

[0053] The purpose of using multiple sound-absorbing components is to fully utilize the coupling resonance effect between them. That is, when components with different frequency responses are combined, their respective frequency bands with resonance peaks can be effectively connected through precise design to form a continuous, wide-band sound absorption characteristic. This synergistic effect not only improves the sound absorption coefficient but also broadens the sound absorption frequency band, enabling it to exert a good sound absorption effect over a wider frequency range.

[0054] It should be noted that each component has different sound absorption performance. The sound absorption coefficient curve of each component can be calculated using finite element analysis or formulas. For the sound absorption coefficient curves derived from theoretical formulas in the specific embodiments given later in the document, such as... Figure 9 As shown, the thin solid line represents the sound absorption performance of a single sound-absorbing cavity, from which the sound absorption peak and its corresponding frequency can be seen; the thick solid line represents the sound absorption performance of the combined structure.

[0055] The designed component, which consists only of a micro-perforated plate and lacks a Helmholtz cavity, exhibits a sound absorption peak, as shown by the thin solid line with a circle.

[0056] A series assembly of a micro-perforated plate and a Helmholtz cavity has two sound absorption peaks generated by the micro-perforated plate and the Helmholtz cavity respectively, as shown by the thin solid line with a rectangle.

[0057] The assembly of a micro-perforated plate connected in series with two Helmholtz cavities exhibits three sound absorption peaks, as shown by the thin solid lines with triangles and hexagons.

[0058] Similarly, components consisting of micro-perforated plates connected in series with multiple Helmholtz cavities have multiple sound absorption peaks;

[0059] The sound absorption performance of the combined structure is shown by the thick solid line. It can be seen that the combined structure can improve the overall sound absorption coefficient and achieve wideband sound absorption.

[0060] Table 1: Peak frequencies corresponding to unit structures (Micro-perforated panel, MPP; Helmholtz resonator, HR)

[0061]

[0062] It should be noted that periodic distribution refers to a pattern in which a phenomenon, data, or event repeats itself in time, space, or other dimensions according to a certain cycle. This distribution has obvious regularity; the repetition interval (cycle) can be fixed or fluctuate within a certain range. Here, it refers to the placement of the first sound-absorbing component 11, the second sound-absorbing component 12, and the third sound-absorbing component 13 according to the sound absorption requirements. For example, the first sound-absorbing component 11, the second sound-absorbing component 12, the third sound-absorbing component 13, and the second sound-absorbing component 12 form a cyclic distribution. The type of cycle is diverse and can be adjusted according to specific needs.

[0063] In some embodiments, two third sound-absorbing components 13 are provided, with the first sound-absorbing component 11, the third sound-absorbing component 13, the second sound-absorbing component 12, and the third sound-absorbing component 13 arranged in an array. The sound absorption performance of a single structure is determined by parameters. When a sound wave is incident perpendicularly, the sound wave in a specific frequency band causes air resonance in the unit structure, thereby converting the energy of that frequency band from sound energy into heat energy and dissipating it, thus completing the absorption of sound waves in that frequency band without absorbing sound waves in other frequency bands. The purpose of using multiple sound-absorbing components is to fully utilize the coupling resonance effect between each sound-absorbing component. That is, when components with different frequency responses are combined, their respective frequency bands with resonance peaks can be effectively connected through precise design to form a continuously covering broadband sound absorption characteristic. This synergistic effect not only improves the sound absorption coefficient but also broadens the sound absorption frequency band, enabling it to exert a good sound absorption effect over a wider frequency range. (e.g.) Figure 9 As shown, the thin solid line represents the sound absorption coefficient curve of a single sound-absorbing cavity, while the thick solid line represents the sound absorption coefficient curve of the combined structure. When multiple components are connected in parallel, a high sound absorption coefficient is achieved across a wider frequency range.

[0064] Based on the parallel embodiments of the above embodiments, the first sound-absorbing component, the second sound-absorbing component, the third sound-absorbing component, and the fourth sound-absorbing component are arranged in an array in sequence. The first sound-absorbing component is provided with a micro-perforated plate, the second sound-absorbing component is provided with a micro-perforated plate and a Helmholtz resonant cavity, the third sound-absorbing component is provided with a micro-perforated plate and two Helmholtz resonant cavities, and the fourth sound-absorbing component is provided with a micro-perforated plate and three Helmholtz resonant cavities.

[0065] In some embodiments, the first housing, second housing, and third housing are integrally formed or spliced ​​together. Each noise reduction component, or even each noise reduction unit, can be an independent structure, integrally formed using processes such as injection molding, which facilitates installation; alternatively, it can be divided into multiple separate structures, such as the upper micro-perforated plate and the lower Helmholtz resonant cavity being spliced ​​together. Each structure is an extremely simple individual component, easy to manufacture, conducive to modular production, and beneficial to production efficiency. During assembly, different numbers of noise reduction units can be selected and spliced ​​according to the specific area, resulting in high applicability.

[0066] In some embodiments, the inner cavity cross-sections of the first sound-absorbing component 11, the second sound-absorbing component 12, and the third sound-absorbing component 13 are circular or rectangular. (1) Advantages of circular cavities: Acoustic performance: The axisymmetric structure reduces standing wave interference and is suitable for scenarios requiring a single resonance peak (such as high-precision sound absorption). Low sensitivity to opening position: Symmetry makes the opening position have less impact on acoustic impedance. (2) Advantages of rectangular cavities: Spatial adaptability: Easy to integrate with building or equipment structures (such as wall sound-absorbing panels 4, electronic device cavities). Processing convenience: Straight edges are easier to cut and splice, resulting in lower costs. Flexible parameter adjustment: Volume and modal distribution can be optimized by adjusting the length, width, and height.

[0067] In some embodiments, the porosity and / or pore size of the first, second, and third microperforated plates are different. Different pore sizes and porosities have different sound absorption coefficients, and setting different parameters results in different sound absorption effects.

[0068] In some embodiments, the internal dimensions of the second and third Helmholtz resonators are different. Different dimensions result in different sound absorption effects.

[0069] In some embodiments, adjacent noise reduction units are tightly connected. This prevents noise from passing through the gaps and improves the noise reduction effect. Adjacent units can be connected by means of glue, welding, or other methods.

[0070] In some embodiments, the dimensions in the L direction of the first housing, the second housing, and the third housing are the same; the dimensions in the W direction of the first housing, the second housing, and the third housing are the same; and the dimensions in the H direction of the first housing, the second housing, and the third housing are the same. The fact that the length, width, and height are all the same facilitates the side-by-side arrangement of the noise reduction components, allowing the noise reduction components to be arranged periodically.

[0071] In some embodiments, the theoretical calculation formula is as follows:

[0072] The acoustic impedance of the first noise reduction component 11, i.e., the micro-perforated plate unit, is:

[0073] Z = Z MPP +Z D (1)

[0074] In the formula: Z MPP Z represents the acoustic impedance of the micro-perforated plate surface. D The acoustic impedance of the micro-perforated plate back cavity is expressed by the following formula:

[0075] Z MPP =z0(r MPP +jωm MPP (2)

[0076]

[0077] In the formula: z0=ρ0c0 represents the characteristic impedance of air, ρ0 and c0 represent the air density and sound velocity, ω=2πf represents the frequency, and h1 represents the depth of the micro-perforated plate back cavity. Furthermore, r MPP and m MPP Let the relative acoustic impedance and relative acoustic mass of the micro-perforated plate be represented, respectively, by the following formulas:

[0078]

[0079] In the formula: θ represents the relative kinematic viscosity coefficient of air, D represents the pore size, t1 represents the plate thickness, and σ represents the porosity. It is expressed as the perforated plate constant.

[0080] The total acoustic impedance of the second noise reduction component 12 or the third noise reduction component 13, i.e., the series unit structure, is:

[0081] Z = Z MPP +1 / (1 / Z D +Z HR (6)

[0082] In the formula, Z HR The total acoustic impedance of the parallel Helmholtz cavities is expressed by the following formula:

[0083]

[0084] In the formula: S = RW represents the total area of ​​the Helmholtz cavity, S i =l i w i Z represents the area of ​​the i-th internal cavity. hri Let be the acoustic impedance of the i-th Helmholtz cavity, expressed by the following formula:

[0085] Z hri =Z hi +Z ci (8)

[0086] In the formula: Z hi and Z ci Let represent the acoustic impedance of the i-th Helmholtz cavity neck and the acoustic impedance of the cavity, respectively, as shown in the following formulas:

[0087]

[0088] Z ci =-jZ cei cot(k cei ·h2) (10)

[0089] In the formula: Let B0 and B1 represent the perforation constant, and B0 and B1 represent the zeroth and first-order Bessel functions of the first kind, respectively. Let Z be the porosity of the i-th Helmholtz cavity. cei and k cei Let represent the effective characteristic impedance and effective transfer constant of the air inside the i-th Helmholtz cavity, respectively, as shown in the following formulas:

[0090]

[0091] In the formula: ρ 0ei and C 0ei These represent the effective density and effective volume compressibility of air, respectively, and are expressed by the following formulas:

[0092]

[0093] In the formula: a = l i and h = w i Let α represent the length and width of the i-th Helmholtz cavity, respectively. m = (m+1 / 2)π / a and β n = (n+1 / 2)π / h represents intermediate calculation constants, P0 = 1.01325·10 5 Pa represents standard atmospheric pressure at room temperature, γ = 1.4 represents the specific heat rate of air, κ = 0.0258 W / (m·K), and C v =718J / (kg·K) represents the thermal conductivity and specific heat capacity of air for an equal volume, respectively.

[0094] Furthermore, the total acoustic impedance of the combined noise reduction unit 1 is:

[0095]

[0096] The sound absorption coefficient of the combined noise reduction unit 1 is:

[0097]

[0098] The sound absorber is a single-cell structure. The sound-absorbing panel 4 structure is formed by periodically combining the unit structures in the horizontal and vertical directions, and the unit cell structures are closely connected.

[0099] Inside power plant industrial buildings, numerous pieces of equipment operate continuously, and low-frequency noise severely impacts the working environment. The overall dimensions of the combined low-frequency broadband sound absorber are L×W×H=70mm×70mm×50mm. Based on the principle of structural resonance sound absorption, when sound waves are incident perpendicularly, sound waves of a specific frequency band cause air resonance within the structure, thereby converting the energy of that frequency band from acoustic energy into heat energy and dissipating it. Through the rational design of components of different forms and dimensional parameters, a low-frequency broadband sound absorption effect is successfully achieved. Figure 4 As shown, each component structure consists of a micro-perforated plate or a Helmholtz resonant cavity and their combination. The overall dimensions of a single component structure are L1×W1×H1=35mm×35mm×50mm. The main dimensional parameters of the micro-perforated plate structure include: pore diameter D, porosity α, plate thickness t1, and back cavity depth h1. The main parameters of the Helmholtz resonant cavity include: pore diameter d, plate thickness t2, h, and the length, width, and height of the internal cavity l, w, and h. In each component structure, the micro-perforated plate and the Helmholtz cavity have the same plate thickness, which is 1 mm and 3 mm, respectively. In the component structure containing two Helmholtz cavities, the apertures are d1 and d2, and the internal cavity length and width are l1×w1=14mm×34mm and l2×w2=19.5mm×34mm, respectively. In the unit structure containing one Helmholtz cavity, the aperture is d1, and the internal cavity length and width are l3×w3=34mm×34mm. Other relevant parameters are shown in Table 1.

[0100] Table 1: Parameters of Sound Absorbing Cavity Unit

[0101]

[0102] To fully verify the practical application effect of the present invention, finite element software was used to perform simulation calculations on the above embodiments. The simulation results show that the sound absorption coefficient curve is as follows: Figure 7 As shown in the figure, the theoretical calculation results are consistent with the simulation results, which fully demonstrates the accuracy of the design of this invention.

[0103] Through the synergistic coupling effect of multiple sound-absorbing units, this invention successfully achieves an excellent sound absorption effect with an average sound absorption coefficient of over 0.7 in the frequency range of 355Hz to 1235Hz, while maintaining an overall thickness of only 50 mm. This achievement not only represents a technological breakthrough but also provides a solid foundation for practical applications.

[0104] To effectively reduce noise levels inside the gas-fired power plant building, we periodically arranged and combined sound absorbers to construct a large-area sound-absorbing panel 4, such as... Figure 8 As shown, these sound-absorbing panels 4 are carefully installed on the walls or ceilings of the plant. When low-frequency sound waves propagate to the perimeter of the room and come into contact with the sound-absorbing panels 4, the energy of the sound waves is efficiently absorbed and dissipated, preventing them from being reflected back into the room. This process significantly reduces the reverberation effect in the room, further reducing the noise level in the gas-fired power plant building and creating a quieter and more comfortable working environment for the staff.

[0105] Through this innovative sound-absorbing design and scientific installation scheme, this invention not only achieves a technological breakthrough in low-frequency broadband sound absorption, but also demonstrates significant noise reduction effects in practical applications, providing an efficient and reliable solution for industrial noise control. It should be noted that this specification may use terms such as "one embodiment," "some embodiments," "basic embodiment," and "extended embodiment" to describe several embodiments of this utility model, and the specific features, structures, materials, or characteristics of these embodiments may be combined in accordance with the principles and spirit of this utility model.

[0106] Although some embodiments of the present utility model have been shown and described in this specification, the present utility model should not be limited to the above embodiments. As long as they achieve the technical effects of the present utility model by the same or equivalent means, any changes, modifications, equivalent substitutions and equivalent variations of these embodiments within the spirit and principles disclosed in the present utility model, without departing from the principles and purpose of the present utility model, should be included within the scope of protection disclosed in the present utility model and should be considered to fall within the protection scope of the present utility model.

Claims

1. A combined noise-reducing sound absorber, characterized in that, include: The first sound-absorbing component (11) includes a first housing and a first micro-perforated plate disposed on the first housing; The second sound-absorbing component (12) includes a second housing, a second micro-perforated plate disposed above the second housing, and a second Helmholtz resonant cavity disposed below the first housing; The third sound-absorbing component (13) includes a third housing, a third micro-perforated plate disposed above the second housing, and a plurality of third Helmholtz resonant cavities disposed below the first housing; The first sound-absorbing component (11), the second sound-absorbing component (12), and the third sound-absorbing component (13) are combined to form a sound-absorbing unit and are arranged periodically.

2. The combined noise-reducing sound absorber according to claim 1, characterized in that: The third sound-absorbing component (13) is provided in two. The first sound-absorbing component (11), the third sound-absorbing component (13), the second sound-absorbing component (12), and the third sound-absorbing component (13) are sequentially combined to form a sound-absorbing unit, and multiple sound-absorbing units are periodically distributed.

3. The combined noise-reducing sound absorber according to claim 1, characterized in that: The first shell, the second shell, and the third shell are integrally formed or spliced ​​together.

4. The combined noise-reducing sound absorber according to claim 1, characterized in that: The inner cavity cross-section of the first sound-absorbing component (11), the second sound-absorbing component (12), and the third sound-absorbing component (13) is circular or rectangular.

5. The combined noise-reducing sound absorber according to claim 1, characterized in that: The porosity and pore size of the first microperforated plate, the second microperforated plate, and the third microperforated plate are different.

6. The combined noise-reducing sound absorber according to claim 1, characterized in that: The second and third Helmholtz resonant cavities have different apertures and internal dimensions.

7. The combined noise-reducing sound absorber according to claim 1, characterized in that: The third sound-absorbing component (13) has multiple third Helmholtz resonant cavities with the same cavity size but different apertures.

8. The combined noise-reducing sound absorber according to claim 1, characterized in that: The dimensions in the L direction are the same in the first housing, the second housing, and the third housing; the dimensions in the W direction are the same in the first housing, the second housing, and the third housing; and the dimensions in the H direction are the same in the first housing, the second housing, and the third housing.

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