Combined noise reduction and sound absorption unit and sound absorption board

Abstract

The invention relates to the technical field of noise control, and discloses a combined noise reduction and sound absorption unit and a sound absorption board, sound absorption unit structures are periodically arranged and combined to form the sound absorption board with a large area, the sound absorption board is installed on an indoor wall or ceiling of a gas power plant, and indoor low-frequency broadband sound absorption and noise reduction are achieved. The sound absorption device comprises a first sound absorption assembly, the first sound absorption assembly comprises a first shell and a first micro-perforated plate arranged on the first shell, and the first micro-perforated plate is arranged on the first shell; the second sound absorption assembly comprises a second shell, a second micro-perforated plate arranged above the second shell and a second Helmholtz resonant cavity arranged below the first shell; the third sound absorption assembly comprises a third shell, a third micro-perforated plate arranged above the second shell and a plurality of third Helmholtz resonant cavities arranged below the first shell; the first sound absorption assembly, the second sound absorption assembly and the third sound absorption assembly are distributed in parallel.

Description

Technical Field

[0001] The present invention relates to the technical field of noise control, in particular to a combined noise reduction and sound absorption unit and a sound absorption panel. Background Art

[0002] With the rapid development of industrial level and economy, enterprises have increasingly strict requirements for the production environment, and noise control has become a key link. In the gas power plant workshop, when many large equipment such as steam turbines, generators, and air compressors are operating, they will release low-frequency noise, and these noise sound pressure levels are high and the duration is long. Long-term exposure to such an environment will damage the hearing of power plant workers, and occupational diseases such as tinnitus and hearing loss will follow. At the same time, it will also cause problems such as fatigue and inattention, thereby increasing the risk of operation errors and seriously threatening the safe production of the power plant.

[0003] Sound absorption treatment of the workshop building is a common and effective means of noise reduction. Usually, sound absorption materials such as porous sound absorption materials and micro-perforated plates are installed on the surfaces such as walls and ceilings. These materials mainly absorb and attenuate the reflected sound through the internal hole structure, reduce the reverberant sound field in the room, and thus reduce the indoor noise. However, traditional porous sound absorption materials and micro-perforated plates have obvious limitations in practical applications. For example, to achieve a low-frequency broadband sound absorption effect, the volume of the sound absorption material is often large, which not only occupies valuable space in the workshop but also may cause a large load on the building body, restricting its wide application in engineering.

[0004] A micro-perforated plate is a plate with tiny holes, and a Helmholtz resonance cavity consists of a closed cavity and a circular long neck communicating with the outside world. Both utilize the resonance principle to achieve sound absorption in a specific frequency band. The micro-perforated plate performs well in mid-high frequency sound absorption, while the Helmholtz resonance cavity has obvious advantages in the low-frequency part. At present, by introducing cavity structures with different resonance frequencies in series or parallel, the sound absorption frequency band can be broadened, but the problem of the overall large thickness still exists. If the thickness is reduced, it will lead to a narrower frequency band and poor low-frequency sound absorption effect.

[0005] Based on the above problems, the present invention proposes a combined low-frequency broadband sound absorber for noise reduction in the gas power plant workshop, combines the micro-perforated plate with the Helmholtz resonance cavity to form a series structure component. On this basis, different forms of micro-perforated plate units and the series structure component are combined together to form a sound absorption unit structure, so that when the thickness is small, the components play a role of frequency complementarity with each other, and thus achieve low-frequency broadband sound absorption. By arranging the unit structure periodically to form a sound absorption panel and installing it on the inner side of the workshop wall, the effect of reducing noise in the workshop is achieved. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a combined noise reduction and sound absorption unit, which forms a sound absorption board with a larger area through the periodic arrangement and combination of the structures of the sound absorber units, and installs the sound absorption board on the indoor walls or ceilings of the gas power plant workshops to achieve indoor low-frequency broadband sound absorption and noise reduction.

[0007] The present invention also provides a sound absorption board having the above-mentioned combined noise reduction and sound absorption unit.

[0008] On the one hand, the combined noise reduction and sound absorption unit according to an embodiment of the present invention includes:

[0009] A first sound absorption component, including a first housing and a first micro-perforated plate provided on the first housing, and the first micro-perforated plate is provided on the first housing;

[0010] A second sound absorption component, including a second housing, a second micro-perforated plate provided above the second housing, and a second Helmholtz resonance cavity provided below the first housing;

[0011] A third sound absorption component, including a third housing, a third micro-perforated plate provided above the second housing, and a plurality of third Helmholtz resonance cavities provided below the first housing;

[0012] According to some embodiments of the present invention, there are two third sound absorption components, and the first sound absorption component, the third sound absorption component, the second sound absorption component, and the third sound absorption component are combined in sequence.

[0013] According to some embodiments of the present invention, the first housing, the second housing, and the third housing are integrally formed or spliced.

[0014] According to some embodiments of the present invention, the cross-sectional areas of the inner cavities of the first sound absorption component, the second sound absorption component, and the third sound absorption component are circular or rectangular.

[0015] 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.

[0016] According to some embodiments of the present invention, the pore diameters and inner cavity dimensions of the second Helmholtz resonance cavity and the third Helmholtz resonance cavity are different.

[0017] On the other hand, the sound absorption board according to an embodiment of the present invention includes the combined noise reduction and sound absorption unit according to the above embodiments of the present invention.

[0018] The embodiments of the present invention have at least the following beneficial effects:

[0019] 1. The composition of multiple groups of sound absorption unit structures

[0020] This design adopts a variety of sound-absorbing component structures to achieve efficient low-frequency broadband sound absorption effect. Specifically, it includes the following component structures:

[0021] Micro-perforated panel: This unit structure utilizes the characteristics of the micro-perforated panel to achieve the sound absorption function through the tiny holes on its surface.

[0022] Component composed of micro-perforated panel and Helmholtz resonator: This component consists of a micro-perforated panel and a Helmholtz resonator, combining the mid-high frequency sound absorption advantages of the micro-perforated panel and the low-frequency sound absorption advantages of the Helmholtz resonator.

[0023] Multi-cavity combined structure: This unit consists of a micro-perforated panel and multiple Helmholtz resonators. Through the synergistic effect of multiple resonators, the sound absorption frequency band is further broadened.

[0024] The size of each unit structure is designed, and its specific structure is as Figure 2 shown, ensuring efficient sound absorption effect in different frequency bands.

[0025] 2. Advantages of the combined low-frequency broadband sound absorber

[0026] The combined low-frequency broadband sound absorber has the following remarkable advantages:

[0027] High-efficiency sound absorption: Through the combination of components with different forms and size parameters, the sound absorption frequencies of each component can be complementary to broaden the sound absorption frequency band range, achieving the purpose of broadband sound absorption; at the same time, using the coupling effect of each component, the overall sound absorption coefficient is enhanced throughout the sound absorption frequency band range to further make up for the deficiencies of traditional sound absorption materials in broadband sound absorption, and achieve a more continuous and efficient sound absorption coefficient.

[0028] Small thickness: The coupling of multiple chambers in this sound absorber makes it have a sub-wavelength scale in thickness, and the overall thickness is significantly smaller than that of traditional sound absorption materials, greatly saving space, especially suitable for industrial environments with limited space.

[0029] Low-frequency broadband sound absorption: The combination of the mid-high frequency sound absorption performance of the micro-perforated panel and the low-frequency sound absorption performance of the Helmholtz resonator makes it perform well in both the low-frequency band and the broadband range, effectively solving the problem of poor sound absorption effect of traditional sound absorption materials in the low-frequency band.

[0030] 3. Sound absorption principle and performance improvement

[0031] Absorption principle of a single structure: The absorption performance of each absorption component is determined by its structural parameters. When sound waves are incident vertically, sound waves in a specific frequency band will excite the resonance of the air in the unit structure. In this process, sound energy is converted into heat energy and dissipated, thereby achieving efficient absorption of sound waves in this frequency band. This design ensures the efficient sound absorption performance of the sound absorber in a specific frequency band.

[0032] Synergistic effect of multiple units: The purpose of using multiple absorption components is to make full use of the coupling resonance effect existing between the components. That is, when components with different frequency responses are combined, through precise design, the frequency bands with resonance peaks of each of them can be effectively connected, forming a broadband sound absorption characteristic with continuous coverage. This synergistic effect not only improves the sound absorption coefficient but also broadens the sound absorption frequency band, enabling it to achieve good sound absorption effects in a wider frequency range.

[0033] 4. Lightweight design and building friendliness

[0034] Easy to install and maintain: Due to the relatively light overall weight, the installation process of the sound absorber is more convenient and fast, reducing the installation time and cost. At the same time, the lightweight design is also beneficial for subsequent maintenance work, further improving its convenience and economy in practical applications.

[0035] Additional aspects and advantages of the present invention will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present invention. Description of the drawings

[0036] Figure 1 is a schematic structural diagram of a combined low-frequency broadband sound absorber provided by an embodiment of the present invention;

[0037] Figure 2 is a perspective structural view of a combined low-frequency broadband sound absorber provided by an embodiment of the present invention;

[0038] Figure 3 is a cross-sectional structural view of a combined low-frequency broadband sound absorber provided by an embodiment of the present invention;

[0039] Figure 4 is a schematic diagram of the structural composition of 4 groups of components of a combined low-frequency broadband sound absorber provided by an embodiment of the present invention;

[0040] Figure 5 is a cross-sectional structural view of a component composed of a micro-perforated plate and a Helmholtz resonator in a combined low-frequency broadband sound absorber provided by an embodiment of the invention;

[0041] Figure 6 is a cross-sectional structural view of a component composed of a micro-perforated plate and two Helmholtz resonators in a combined low-frequency broadband sound absorber provided by an embodiment of the invention;

[0042] Figure 7 It is a schematic diagram of the simulation of the sound absorption coefficient curve structure of a combined low-frequency broadband sound absorber provided by an embodiment of the present invention;

[0043] Figure 8 It is a schematic diagram of the structure of the sound absorption plates arranged periodically provided by an embodiment of the present invention;

[0044] Figure 9 It is a schematic diagram of the simulation of the comparison between a single element and multiple elements of the sound absorption coefficient curve structure of the present invention;

[0045] Icons: 1. Combined sound absorption unit, 11. First sound absorption component: micro-perforated plate, 12. Second sound absorption component: a component structure composed of a micro-perforated plate and a Helmholtz resonator, 13, 14. Third sound absorption component: a component structure composed of a micro-perforated plate and multiple Helmholtz resonators, 21. Micro-perforated plate structure, 22. Helmholtz cavity structure, 31. Micro-perforated plate structure, 32, 33. Helmholtz cavity structures, 4. Sound absorption plate Specific embodiments

[0046] The following content will describe several embodiments of the present invention, including the embodiments corresponding to the attached drawings. It can be understood that the attached drawings are used to assist in understanding the technical features and technical solutions of the present invention, and should not be construed as a limitation on the protection scope of the present invention.

[0047] The following will clearly and completely describe the concept, specific structure and technical effects generated by the present invention in combination with the embodiments and the attached drawings, so as to fully understand the purpose, solution and effects of the present invention. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0048] It should be noted that unless otherwise clearly defined, when a certain feature is referred to as "fixed", "connected", "installed" to another feature, it can be directly fixed or connected to another feature, or indirectly fixed or connected to another feature. The words "fixed", "connected", "installed", etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0049] It should be noted that the descriptions of the orientation or positional relationships indicated by up, down, left, right, top, bottom, front, back, inside, outside, etc. in the present invention are based on the orientation or positional relationships in the attached drawings or embodiments, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on the present invention.

[0050] It should be noted that the term "and / or" used in the present invention includes any combination of one or more of the related listed items. The meaning of "several" is one or more, the meaning of "multiple" is two or more, and understandings such as "greater than", "less than", and "exceeding" do not include the present number, while understandings such as "above", "below", and "within" include the present number.

[0051] It should be noted that if the first and second are described in the present invention, it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0052] It should be noted that unless otherwise clearly defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art of this technology. The terms used in the description of this specification are only for describing specific embodiments and are not intended to limit the present invention.

[0053] Referring to Figures 1-9 , the basic embodiment of the first aspect of the present invention provides a combined noise reduction and sound absorption unit, including:

[0054] The first sound absorption component 11 includes a first housing and a first micro-perforated plate provided in the first housing, and the first micro-perforated plate is provided in the first housing;

[0055] The second sound absorption component 12 includes a second housing, a second micro-perforated plate provided above the second housing, and a second Helmholtz resonance cavity provided below the first housing;

[0056] The third sound absorption component 13 includes a third housing, a third micro-perforated plate provided above the second housing, and a plurality of third Helmholtz resonance cavities provided below the first housing;

[0057] The first sound absorption component 11, the second sound absorption component 12, and the third sound absorption component 13 are arranged side by side.

[0058] Referring to Figure 8 , the basic embodiment of the second aspect of the present invention provides a sound absorption panel, including a plurality of combined noise reduction and sound absorption units, and the plurality of combined noise reduction and sound absorption units are arranged periodically.

[0059] According to the embodiments of the present invention, by setting like this, at least the following effects can be achieved. Multiple groups of sound absorption component structures: a micro-perforated plate component structure, a component structure composed of a micro-perforated plate and a Helmholtz resonance cavity, and two component structures composed of a micro-perforated plate and multiple Helmholtz resonance cavities. Each component structure is as Figure 2 shown;

[0060] The combined low-frequency broadband sound absorber has the advantages of a smaller thickness and a sub-wavelength scale;

[0061] By combining different forms of units instead of simply connecting them in series or parallel, the deficiencies in broadband sound absorption can be further compensated, making it have a more continuous and efficient sound absorption coefficient.

[0062] Combining the good high- and mid-frequency sound absorption performance of the micro-perforated panel with the good low-frequency performance of the Helmholtz resonator gives it the advantage of low-frequency broadband sound absorption.

[0063] The sound absorption performance of a single structure is determined by parameters. When sound waves are incident perpendicularly, sound waves in a specific frequency band cause the air in the unit structure to resonate, and then the energy of this frequency band is converted from sound energy into heat energy and dissipated, completing the absorption of sound waves in this frequency band without absorbing sound waves in other frequency bands.

[0064] The purpose of using multiple sound absorption components is to make full use of the coupling resonance effect existing between the sound absorption components. That is, when components with different frequency responses are combined, through precise design, the frequency bands with resonance peaks of each of them can be effectively connected, forming a wide-frequency sound absorption characteristic with continuous coverage. This synergistic effect not only improves the sound absorption coefficient but also broadens the sound absorption frequency band, enabling it to achieve good sound absorption effects within a wider frequency range. It should be noted that each component has different sound absorption performances, and the sound absorption coefficient curves of each component can be calculated through finite elements or formulas. For 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 absorption component, 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.

[0065] The designed component with only a micro-perforated panel and no Helmholtz cavity has a sound absorption peak, as shown by the thin solid line with a circle.

[0066] The series component of a micro-perforated panel and a Helmholtz cavity has two sound absorption peaks generated by the micro-perforated panel and the Helmholtz cavity respectively, as shown by the thin solid line with a rectangle.

[0067] The component of a micro-perforated panel in series with two Helmholtz cavities has three sound absorption peaks, as shown by the thin solid lines with a triangle and a hexagon.

[0068] And so on, the component of a micro-perforated panel in series with multiple Helmholtz cavities has multiple sound absorption peaks.

[0069] The sound absorption performance of the combined structure is shown by the red hollow line. It can be seen that the combined structure can overall improve the sound absorption coefficient and achieve wide-frequency sound absorption.

[0070] Table 1: Peak frequencies corresponding to unit structures (Micro-perforated panel, MPP; Helmholtz resonator, HR)

[0071]

[0072] It should be noted that the meaning of periodic distribution is that a periodic distribution refers to a distribution pattern in which a certain phenomenon, data, or event repeats at regular intervals in time, space, or other dimensions. This distribution has obvious regularity, and the repeated interval period can be fixed or fluctuate within a certain range. Here, it refers to setting the positions of the sound-absorbing components by the first sound-absorbing component 11, the second sound-absorbing component 12, and the third sound-absorbing component 13 according to the needs of sound absorption. For example, 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 form a combination. The types of combinations here are diverse and are adjusted according to specific needs.

[0073] In some embodiments, there are two third sound-absorbing components 13, and 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 arranged in an array in sequence. The sound-absorbing performance of a single structure is determined according to parameters. When sound waves are vertically incident, sound waves in a specific frequency band cause the air in the unit structure to resonate, and then the energy in this frequency band is converted from sound energy into heat energy and dissipated, completing the absorption of sound waves in this frequency band, and not absorbing sound waves in other frequency bands. The purpose of using multiple sound-absorbing components is to make full use of the coupling resonance effect existing between the sound-absorbing components. 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 broadband sound-absorbing characteristic with continuous coverage. This synergistic effect not only improves the sound-absorbing coefficient but also broadens the sound-absorbing frequency band. (Example: As Figure 9 shown, the thin solid line represents the sound-absorbing coefficient curve of a single sound-absorbing cavity, and the thick solid line represents the sound-absorbing coefficient curve of the combined structure. When multiple components are combined in parallel, there is a relatively high sound-absorbing coefficient in a large frequency range.)

[0074] 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 microporous perforated plate, the second sound-absorbing component is provided with a microporous perforated plate and a Helmholtz resonance cavity, the third sound-absorbing component is provided with a microporous perforated plate and two Helmholtz resonance cavities, and the fourth sound-absorbing component is provided with a microporous perforated plate and three Helmholtz resonance cavities.

[0075] In some embodiments, the first housing, the second housing, and the third housing are integrally formed or joined together. Each sound absorption component or even each noise reduction unit can be an independent structure, integrally formed by means of processes such as injecting glue, which is beneficial for installation; it can also be divided into multiple split structures. For example, the upper micro-perforated plate and the lower Helmholtz resonator are joined together. Each structure is an extremely simple individual component, easy to produce, which is beneficial for modular production and production efficiency. During assembly, it can be assembled according to the specific area, select different numbers of noise reduction units for splicing, and has high applicability.

[0076] In some embodiments, the inner cavity cross-sections of the first sound absorption component 11, the second sound absorption component 12, and the third sound absorption component 13 are circular or rectangular. (1) Advantages of a circular cavity: 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 the opening position: The symmetry makes the opening position have less influence on the acoustic impedance. (2) Advantages of a rectangular cavity: Spatial adaptability: It is easy to integrate with building or equipment structures (such as wall sound absorption panels, electronic equipment cavities). Processing convenience: The straight edges are easier to cut and join, with lower costs. Flexible parameter adjustment: The volume and modal distribution can be optimized by adjusting the length, width, and height.

[0077] In some embodiments, the porosity and pore size of the first micro-perforated plate, the second micro-perforated plate, and the third micro-perforated plate are different. Different pore sizes and porosities have different sound absorption coefficients. By setting different parameters, different sound absorption effects can be achieved.

[0078] In some embodiments, the pore sizes and inner cavity volume size parameters of the second Helmholtz resonator and the third Helmholtz resonator are different. By setting different size parameters, different sound absorption and noise reduction effects can be achieved.

[0079] In some embodiments, adjacent noise reduction units are tightly connected. This prevents noise from passing through the gaps, improving the noise prevention effect. Adjacent units can be connected by means such as glue or welding.

[0080] 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 lengths of the length, width, and height are all the same, which is beneficial for arranging the sound absorption component structures side by side, enabling the sound absorption components to be arranged periodically.

[0081] In some embodiments, the theoretical calculation formula is:

[0082] Among them, the acoustic impedance of the first sound absorption component 11, that is, the micro-perforated plate unit, is:

[0083] Z = Z MPP+Z D (1)

[0084] Where: Z MPP represents the acoustic impedance rate of the micro-perforated plate surface, and Z D represents the acoustic impedance rate of the micro-perforated plate back cavity. The formula is as follows:

[0085] Z MPP = z0(r MPP + jωm MPP ) (2)

[0086]

[0087] Where: z0 = ρ0c0 represents the characteristic impedance of air, ρ0 and c0 represent air density and sound velocity, ω = 2πf represents frequency, and h1 represents the depth of the micro-perforated plate back cavity. In addition, r MPP and m MPP respectively represent the relative acoustic resistance and relative acoustic mass of the micro-perforated plate. The formula is as follows:

[0088]

[0089]

[0090] Where: θ represents the relative kinematic viscosity coefficient of air, D represents the pore diameter, t1 represents the plate thickness, σ represents the porosity, represents the perforated plate constant.

[0091] Among them, the total acoustic impedance of the second sound absorption component 12 or the third sound absorption component 13, that is, the series unit structure, is:

[0092] Z = Z MPP + 1 / (1 / Z D + Z HR ) (6)

[0093] Where, Z HR represents the total acoustic impedance of the parallel Helmholtz cavity. The formula is as follows:

[0094]

[0095] Where: S = RW represents the total area of the Helmholtz cavity, S i = l i w i represents the area of the i-th internal cavity, and Z hri represents the acoustic impedance of the i-th Helmholtz cavity. The formula is as follows:

[0096] Z hri = Z hi + Z ci(8)

[0097] In the formula: Z hi and Z ci respectively represent the acoustic impedance of the long neck of the i-th Helmholtz cavity and the acoustic impedance of the cavity. The formulas are as follows:

[0098]

[0099] Z ci =-jZ cei cot(k cei ·h2) (10)

[0100] In the formula: represents the perforation constant, B0 and B1 respectively represent the zero-order and first-order Bessel functions of the first kind, represents the porosity of the i-th Helmholtz cavity, Z cei and k cei respectively represent the effective characteristic impedance and effective transfer constant of the air in the i-th Helmholtz cavity. The formulas are as follows:

[0101]

[0102]

[0103] In the formula: ρ 0ei and C 0ei respectively represent the effective density and effective volume compressibility of the air. The formulas are as follows:

[0104]

[0105]

[0106]

[0107]

[0108] In the formula: a = l i and h = w i respectively represent the length and width of the i-th Helmholtz cavity, α m =(m + 1 / 2)π / a and β n =(n + 1 / 2)π / h respectively represent intermediate calculation constants, P0 = 1.01325·10 5 Pa represents the standard atmospheric pressure at normal temperature, γ = 1.4 represents the specific heat ratio of the air, κ = 0.0258 W / (m·K) and C v = 718 J / (kg·K) respectively represent the thermal conductivity and specific heat capacity of the air at constant volume.

[0109] Furthermore, the total acoustic impedance of the combined noise reduction and sound absorption unit is:

[0110]

[0111] Among them, the sound absorption coefficient of the combined noise reduction and sound absorption unit is:

[0112]

[0113] Among them, the sound absorber is a unit structure, and the sound absorption plate 4 structure is formed by periodically combining the unit structure in the horizontal and vertical directions, and the single cell structures are tightly connected to each other.

[0114] In the industrial plant of a power plant, a large number of equipment operate continuously, and the low-frequency noise problem seriously affects the working environment. The overall external dimensions of the combined low-frequency broadband sound absorber are L×W×H = 70mm×70mm×50mm. Based on the resonance sound absorption principle of the structure, when sound waves are vertically incident, sound waves in a specific frequency band cause the air in the structure to resonate, and then the energy of this frequency band is converted from sound energy into heat energy and dissipated. By reasonably designing the component structures of different forms and different size parameters, the sound absorption effect of low-frequency broadband is successfully achieved. As Figure 4 shown, each component structure is composed of a micro-perforated plate or a Helmholtz resonator and their combined structures. The overall external dimensions of a single component structure are L1×W1×H1 = 35mm×35mm×50mm. The size parameters of the micro-perforated plate mainly include: pore diameter D, porosity α, plate thickness t1, and back cavity depth h1. The main parameters of the Helmholtz resonator include: pore diameter d, plate thickness t2, h, and the length, width, and height l, w, h2 of the internal cavity. The plate thickness dimensions of the micro-perforated plate and the Helmholtz cavity in each component structure are the same, which are 1mm and 3mm respectively. The component

[0115] structure containing two Helmholtz cavities has pore diameters of d1 and d2 respectively, and the internal cavity lengths and widths are l1×w1 = 14mm×34mm and l2×w2 = 19.5mm×34mm. The unit structure containing one Helmholtz cavity has a pore diameter of d1, and the internal cavity length and width are l3×w3 = 34mm×34mm. The remaining relevant parameters are shown in Table 1.

[0116] Table 2: Parameters of the sound absorption cavity unit

[0117]

[0118] In order to comprehensively verify the actual application effect of the present invention, the above embodiments were simulated and calculated using finite element software. The simulation results show that the sound absorption coefficient curve is as Figure 7 shown. It can be clearly seen from the figure that the theoretical calculation results are consistent with the simulation results, which fully proves the accuracy of the design of the present invention.

[0119] Through the synergistic coupling effect of multiple groups of sound-absorbing components, the present invention has successfully achieved an excellent sound-absorbing effect with an average sound-absorption coefficient of over 0.7 in the frequency range of 355 Hz to 1235 Hz under the condition that the overall thickness is only 50 millimeters. This achievement not only represents a technological breakthrough but also provides a solid foundation for practical applications.

[0120] In order to effectively reduce the noise level in the plant of a gas-fired power plant, we arranged and combined the sound absorbers periodically to construct a large-area sound-absorbing panel 4, as Figure 8 shown. These sound-absorbing panels 4 are carefully installed on the walls or ceilings inside the plant building. When low-frequency sound waves propagate to the surrounding of the room and contact the sound-absorbing panels 4, the energy of the sound waves will be efficiently absorbed and dissipated, so that they cannot be reflected back into the indoor space. This process significantly weakens the reverberation effect in the room and further reduces the noise level in the plant of the gas-fired power plant, creating a quieter and more comfortable working environment for the staff.

[0121] Through this innovative sound-absorbing design and scientific installation scheme, the present invention not only achieves a breakthrough in low-frequency broadband sound absorption technically but also demonstrates a remarkable noise reduction effect in practical applications, providing an efficient and reliable solution for industrial noise control. It should be noted that in this specification, terms such as "one embodiment", "some embodiments", "basic embodiment", "extended embodiment" can be used to describe several embodiments of the present invention. The specific features, structures, materials or characteristics in several embodiments can be combined under the premise of conforming to the principles and purposes of the present invention.

[0122] Although some embodiments of the present invention have been shown and described in this specification, the present invention should not be limited to the above embodiments. As long as it achieves the technical effects of the present invention by the same or equivalent means, any changes, modifications, equivalent substitutions, and equivalent variations made to these embodiments within the spirit and principles disclosed in the present invention without departing from the principles and purposes of the present invention should be included within the scope of protection disclosed by the present invention and should be considered to be within the scope of protection of the present invention.

Claims

1. A combined noise reduction and sound absorption unit, characterized in that, Comprising: A first sound absorption component (11), including a first housing and a first micro-perforated plate provided on the first housing, the first micro-perforated plate being provided on the first housing; A second sound absorption component (12), including a second housing, a second micro-perforated plate provided above the second housing, and a second Helmholtz resonance cavity provided below the first housing; A third sound absorption component (13), including a third housing, a third micro-perforated plate provided above the second housing, and a plurality of third Helmholtz resonance cavities provided below the first housing; The first sound absorption component (11), the second sound absorption component (12), and the third sound absorption component (13) are arranged side by side.

2. The combined noise reduction and sound absorption unit according to claim 1, wherein: There are two third sound absorption components (13), and the first sound absorption component (11), the third sound absorption component (13), the second sound absorption component (12), and the third sound absorption component (13) are combined.

3. The combined noise reduction and sound absorption unit according to claim 1, wherein: The first housing, the second housing, and the third housing are integrally formed or spliced.

4. The combined noise reduction and sound absorption unit according to claim 1, characterized in that: The inner cavity cross-sections of the first sound absorption component (11), the second sound absorption component (12), and the third sound absorption component (13) are circular or rectangular.

5. The combined noise reduction and sound absorption unit according to claim 1, wherein: The porosity and pore size on the first micro-perforated plate, the second micro-perforated plate, and the third micro-perforated plate are different.

6. The combined noise reduction and sound absorption unit according to claim 1, characterized in that: The pore diameters and inner cavity sizes of the second Helmholtz resonance cavity and the third Helmholtz resonance cavity are different.

7. A sound-absorbing panel, characterized in that: Comprising a plurality of combined noise reduction and sound absorption units as described in any one of claims 1 to 8, and the plurality of combined noise reduction and sound absorption units are arranged in a periodic distribution.

8. The sound-absorbing panel according to claim 7, wherein: Adjacent combined noise reduction and sound absorption units are tightly connected.

Images