阅读说明：本技术 管道消声器、装置及制备方法 (Pipeline silencer, device and manufacturing method ) 是由 陈建栋 黄唯纯 马仁杰 解龙翔 钟雨豪 颜学俊 钱斯文 卢明辉 詹喆 王乐 于 2020-12-11 设计创作，主要内容包括：本申请提供一种管道消声器、装置及制备方法。管道消声器包括：消声器罩壳,具有第一侧和第二侧,第一侧上开设有进风口,第二侧上开设有与进风口对应的出风口；管道,一端与进风口连接,另一端与出风口连接,管道的壁上开设有第一微孔阵列,相邻两个第一微孔之间具有间隔；以及超构消声单元,设于消声器罩壳内部,超构消声单元沿管道周向、环绕设置在管道的外侧,超构消声单元与管道之间具有间隙；其中,管道具有第一声阻抗,超构消声单元具有第二声阻抗,第一声阻抗和第二声阻抗叠加形成管道消声器的整体声阻抗,在预设频段内,整体声阻抗与空气的阻抗相匹配。上述管道消声器对低频段声波具有较好的消除效果。(The application provides a pipeline silencer, a pipeline silencer device and a manufacturing method. The pipe muffler includes: the silencer housing is provided with a first side and a second side, the first side is provided with an air inlet, and the second side is provided with an air outlet corresponding to the air inlet; one end of the pipeline is connected with the air inlet, the other end of the pipeline is connected with the air outlet, a first micropore array is arranged on the wall of the pipeline, and a space is formed between every two adjacent first micropores; the super-structure noise elimination unit is arranged in the silencer housing, is arranged on the outer side of the pipeline in a surrounding manner along the circumferential direction of the pipeline, and has a gap with the pipeline; the pipeline is provided with a first acoustic impedance, the super-structure sound elimination unit is provided with a second acoustic impedance, the first acoustic impedance and the second acoustic impedance are superposed to form an integral acoustic impedance of the pipeline silencer, and the integral acoustic impedance is matched with the impedance of air in a preset frequency band. The pipeline silencer has a good eliminating effect on low-frequency sound waves.)

1. A pipe muffler, comprising:

the silencer cover shell is provided with a first side and a second side, the first side is provided with an air inlet, and the second side is provided with an air outlet corresponding to the air inlet;

one end of the pipeline is connected with the air inlet, the other end of the pipeline is connected with the air outlet, a first micropore array is arranged on the wall of the pipeline, and a space is formed between every two adjacent first micropores; and the number of the first and second groups,

the super-structure noise elimination unit is arranged in the silencer housing, the super-structure noise elimination unit is arranged on the outer side of the pipeline in a surrounding manner along the circumferential direction of the pipeline, and a gap is formed between the super-structure noise elimination unit and the pipeline;

wherein the pipe has a first acoustic impedance Z_mSaid super-structure sound-deadening unit having a second acoustic impedance Z_cSaid first acoustic impedance Z_mAnd the second acoustic impedance Z_cThe integral acoustic impedance Z of the pipeline silencer is formed by superposition, and in a preset frequency band, the integral acoustic impedance Z and the impedance Z of air₀And (4) matching.

2. The pipe muffler according to claim 1, wherein the super sound deadening unit has a plurality.

3. The pipe muffler according to claim 1 or 2,

the super-structure noise elimination unit comprises a Helmholtz resonator array, each Helmholtz resonator array is provided with an opening side and a closed side which are arranged oppositely, the opening side faces the pipeline and is provided with second micropores, and the second micropores are communicated with the gaps; and the number of the first and second electrodes,

the open sides of the Helmholtz resonators are located in the same plane, and the second acoustic impedance Z_cSatisfies the following conditions:wherein Z_nRepresenting the surface acoustic impedance of the helmholtz resonator and n representing the ordinal number of the helmholtz resonator.

4. The duct muffler of claim 3, wherein the Helmholtz resonator comprises:

the resonator housing is provided with a third side and a fourth side which are oppositely arranged, the third side faces the pipeline and is provided with the second micropore; and the number of the first and second groups,

and the insertion pipe is arranged in the resonator housing, is connected with the third side and extends towards the fourth side, is coaxial with the second micropore, and has the same pore diameter as the second micropore.

5. The pipe muffler of claim 4, wherein the surface acoustic impedance Z of the Helmholtz resonator is_nSatisfies the following conditions:

wherein A represents the area of the entire third side, S_aRepresents an opening area of the second micro-hole,/' represents a length of the cannula, L represents a vertical distance from the inner surface of the third side to the inner surface of the fourth side, ρ_cc、c_ccAnd k_ccRepresenting the density, speed of sound and wave number, k, respectively, of the air in the Helmholtz resonator_ca、Ψ_vaAnd Ψ_haRespectively represents wave number, viscosity term and thermal term of the cannula under narrow acoustics, gamma represents specific heat capacity of air, and delta_ΩRepresenting an acoustic mass end correction term, τ_ΩDenotes a correction factor, S_cDenotes an area of the inner surface of the fourth side, ω denotes an angular frequency, η denotes a viscosity coefficient of air, ρ₀Denotes the density of air under natural conditions, c₀Representing the speed of sound propagation in the ambient air.

6. The pipe muffler according to claim 1 or 2, wherein the material of the super sound attenuating unit comprises plastic, metal, or soft rubber.

7. The pipe muffler of claim 1 or 2, wherein the first acoustic impedance Z_mSatisfies the following conditions:

wherein the content of the first and second substances,eta represents the viscosity coefficient of air, rho₀Denotes the density of air under natural conditions, c₀Represents the propagation velocity of sound in the outside air, σ represents the porosity of the pipe, ω represents the angular frequency, t represents the wall thickness of the pipe, and d represents the pore diameter of the first micropores.

8. A pipe silencer assembly comprising a plurality of pipe silencers as defined in any of claims 1 to 7 connected in series.

9. A method for manufacturing a pipeline silencer comprises a silencer housing, a silencer cover plate and a silencer, wherein the silencer housing is provided with a first side and a second side, the first side is provided with an air inlet, and the second side is provided with an air outlet corresponding to the air inlet; one end of the pipeline is connected with the air inlet, the other end of the pipeline is connected with the air outlet, a first micropore array is arranged on the wall of the pipeline, and a space is formed between every two adjacent first micropores; the Helmholtz resonator array is arranged in the silencer housing, is arranged on the outer side of the pipeline in a surrounding way along the circumferential direction of the pipeline, and has a gap with the pipeline; the Helmholtz resonators comprise resonator housings and are provided with a third side and a fourth side which are arranged oppositely, the third side faces the pipeline and is provided with a second micropore, the second micropore is communicated with the gap, and the third sides of two adjacent Helmholtz resonators are arranged in contact; and a cannula disposed inside the resonator housing, connected to the third side and extending toward the fourth side, the cannula being coaxial with the second micro-hole and having a bore diameter equal to that of the second micro-hole;

the preparation method is characterized by comprising the following steps:

obtaining a first acoustic impedance function Z of the pipe_m(σ, t, d), wherein σ represents the porosity of the pipe, t represents the wall thickness of the pipe, d represents the pore size of the first micropores;

obtaining a second acoustic impedance function Z of the array of Helmholtz resonators_c(l_n，V_n，R_nN) in which l_nRepresents the cannula length, V_nIndicating the volume of the resonance chamber in the Helmholtz resonator, R_nRepresents a radius of the second micropore, n represents an ordinal number of the Helmholtz resonator;

according to said first acoustic impedance function Z_m(σ, t, d) and the second acoustic impedance function Z_c(l_n，V_n，R_nN) obtaining the overall acoustic impedance function Z (sigma, t, d, l) of the pipe muffler_n，V_n，R_n，n)；

Providing a target frequency band;

for the target frequency band, according to the overall acoustic impedance function Z (sigma, t, d, l)_n，V_n，R_nN) determining the overall acoustic impedance Z and the impedance Z of air₀When matched, the porosity sigma of the pipe, the wall thickness t of the pipe, the aperture d of the first micropore, and the cannula length l of each Helmholtz resonator_nVolume V of the resonance chamber_nAnd a radius R of the second micropores_n；

Will σ, t, d and l_n、V_n、R_nApplied to the duct and the array of Helmholtz resonators, respectively.

10. The production method of a pipe muffler according to claim 9,

according to the sound absorption coefficient of the pipeline silencerDetermining the corresponding porosity sigma of the pipeline, the wall thickness t of the pipeline, the aperture d of the first micropore and the cannula length l of each Helmholtz resonator when the sound absorption coefficient alpha is maximum in the target frequency band_nVolume V of the resonance chamber_nAnd a radius R of the second micropores_nAnd the impedance matching parameters of the pipeline silencer are obtained.

Technical Field

The invention relates to the technical field of silencer parts, in particular to a pipeline silencer, a pipeline silencer device and a manufacturing method.

Background

With the increase of national material level, the comfort requirement of people on daily life is gradually increased, wherein the noise problem becomes a main factor influencing the life comfort. Among them, duct noises widely exist in various air inlets and air outlets, and duct mufflers are widely used in ventilation duct systems as elements that can allow air circulation and reduce sound transmission.

However, the main form of the conventional pipeline muffler is a perforated plate plus glass fiber sound absorption cotton form, which is limited by the sound absorption characteristics of the sound absorption cotton, so that the sound absorption effect of the low frequency band is poor, and the requirement of a user on eliminating the low frequency band noise cannot be met. In addition, the sound absorption cotton is easy to age to become dust which enters air through the air inlet and the air outlet, so that serious dust pollution is caused, and the health of people is harmed.

Disclosure of Invention

Based on this, it is necessary to provide an improved pipe silencer to solve the problems that the traditional pipe silencer has poor low-frequency sound absorption effect and the sound absorption cotton is easy to age to cause environmental pollution.

A pipe muffler comprising:

the silencer cover shell is provided with a first side and a second side, the first side is provided with an air inlet, and the second side is provided with an air outlet corresponding to the air inlet;

one end of the pipeline is connected with the air inlet, the other end of the pipeline is connected with the air outlet, a first micropore array is arranged on the wall of the pipeline, and a space is formed between every two adjacent first micropores; and the number of the first and second groups,

the super-structure noise elimination unit is arranged in the silencer housing, the super-structure noise elimination unit is arranged on the outer side of the pipeline in a surrounding manner along the circumferential direction of the pipeline, and a gap is formed between the super-structure noise elimination unit and the pipeline;

wherein the pipe has a first acoustic impedance Z_mSaid super-structure sound-deadening unit having a second acoustic impedance Z_cSaid first acoustic impedance Z_mAnd the second acoustic impedance Z_cThe integral acoustic impedance Z of the pipeline silencer is formed by superposition, and in a preset frequency band, the integral acoustic impedance Z and the impedance Z of air₀And (4) matching.

According to the pipeline silencer, the overall acoustic impedance of the pipeline and the super-structure silencing unit is matched with the acoustic impedance of air, so that the pipeline silencer has the maximum sound absorption coefficient and a better sound absorption effect; meanwhile, the super-structure sound attenuation unit is adopted to replace traditional sound absorption materials such as glass wool, cotton felt and the like in the traditional sound absorber, so that the sound absorption performance of the pipeline sound absorber in a low-frequency section can be enhanced, and the traditional sound absorption materials are prevented from aging to pollute the environment; in addition, the pipeline silencer can reasonably adjust the structural parameters of the pipeline and the super-structure silencing unit according to the silencing frequency band required by a user, so that the working frequency band of the pipeline silencer is perfectly matched with the requirement of the user.

In one embodiment, the super-structure sound attenuation unit is provided with a plurality of units.

In one embodiment, the metamaterial noise elimination unit comprises an array of helmholtz resonators, each helmholtz resonator has an open side and a closed side which are oppositely arranged, the open side faces the pipeline and is provided with a second micropore, and the second micropore is communicated with the gap; and the open sides of the Helmholtz resonators are located in the same plane,the second acoustic impedance Z_cSatisfies the following conditions:wherein Z_nRepresenting the surface acoustic impedance of the helmholtz resonator and n representing the ordinal number of the helmholtz resonator.

In one embodiment, the helmholtz resonator includes: the resonator housing is provided with a third side and a fourth side which are oppositely arranged, the third side faces the pipeline and is provided with the second micropore; and the insertion pipe is arranged in the resonator housing, is connected with the third side and extends towards the fourth side, is coaxial with the second micropore, and has the same pore diameter as the second micropore.

In one embodiment, the surface acoustic impedance Z of the Helmholtz resonator_nSatisfies the following conditions:

wherein A represents the area of the entire third side, S_aRepresents an opening area of the second micro-hole,/' represents a length of the cannula, L represents a vertical distance from the inner surface of the third side to the inner surface of the fourth side, ρ_cc、c_ccAnd k_ccRepresenting the density, speed of sound and wave number, k, respectively, of the air in the Helmholtz resonator_ca、Ψ_vaAnd Ψ_haRespectively represents wave number, viscosity term and thermal term of the cannula under narrow acoustics, gamma represents specific heat capacity of air, and delta_ΩRepresenting an acoustic mass end correction term, τ_ΩDenotes a correction factor, S_cDenotes an area of the inner surface of the fourth side, ω denotes an angular frequency, η denotes a viscosity coefficient of air, ρ₀Denotes the density of air under natural conditions, c₀Representing the speed of sound propagation in the ambient air.

In one embodiment, the material of the super-structure sound attenuation unit comprises plastic, metal or soft rubber.

At itIn one embodiment, the first acoustic impedance Z_mSatisfies the following conditions:

wherein the content of the first and second substances,eta represents the viscosity coefficient of air, rho₀Denotes the density of air under natural conditions, c₀Represents the propagation velocity of sound in the outside air, σ represents the porosity of the pipe, ω represents the angular frequency, t represents the wall thickness of the pipe, and d represents the pore diameter of the first micropores.

The application also provides a pipeline silencing device.

A pipe silencer assembly comprising a plurality of pipe silencers as defined above connected in series.

The pipeline silencer can effectively eliminate the noise at the air inlet and the air outlet, and improves the living comfort of people; meanwhile, environmental pollution caused by aging of the traditional sound absorption material can be avoided.

The application also provides a preparation method of the pipeline silencer.

A method for manufacturing a pipeline silencer comprises a silencer housing, a silencer cover plate and a silencer, wherein the silencer housing is provided with a first side and a second side, the first side is provided with an air inlet, and the second side is provided with an air outlet corresponding to the air inlet; one end of the pipeline is connected with the air inlet, the other end of the pipeline is connected with the air outlet, a first micropore array is arranged on the wall of the pipeline, and a space is formed between every two adjacent first micropores; the Helmholtz resonator array is arranged in the silencer housing, is arranged on the outer side of the pipeline in a surrounding way along the circumferential direction of the pipeline, and has a gap with the pipeline; the Helmholtz resonators comprise resonator housings and are provided with a third side and a fourth side which are arranged oppositely, the third side faces the pipeline and is provided with a second micropore, the second micropore is communicated with the gap, and the third sides of two adjacent Helmholtz resonators are arranged in contact; and a cannula disposed inside the resonator housing, connected to the third side and extending toward the fourth side, the cannula being coaxial with the second micro-hole and having a bore diameter equal to that of the second micro-hole;

the preparation method comprises the following steps:

obtaining a first acoustic impedance function Z of the pipe_m(σ, t, d), wherein σ represents the porosity of the pipe, t represents the wall thickness of the pipe, d represents the pore size of the first micropores;

obtaining a second acoustic impedance function Z of the array of Helmholtz resonators_c(l_n，V_n，R_nN) in which l_nRepresents the cannula length, V_nIndicating the volume of the resonance chamber in the Helmholtz resonator, R_nRepresents a radius of the second micropore, n represents an ordinal number of the Helmholtz resonator;

according to said first acoustic impedance function Z_m(σ, t, d) and the second acoustic impedance function Z_c(l_n，V_n，R_nN) obtaining the overall acoustic impedance function Z (sigma, t, d, l) of the pipe muffler_n，V_n，R_n，n)；

Providing a target frequency band;

for the target frequency band, according to the overall acoustic impedance function Z (sigma, t, d, l)_n，V_n，R_nN) determining the overall acoustic impedance Z and the impedance Z of air₀When matched, the porosity sigma of the pipe, the wall thickness t of the pipe, the aperture d of the first micropore, and the cannula length l of each Helmholtz resonator_nVolume V of the resonance chamber_nAnd a radius R of the second micropores_n；

Will σ, t, d and l_n、V_n、R_nApplied to the duct and the array of Helmholtz resonators, respectively.

The preparation method of the pipeline silencer can prepare the pipeline silencer with good low-frequency sound absorption effect; meanwhile, structural parameters of the pipeline and the Helmholtz resonator array when impedance matching is met can be determined according to the target frequency band by utilizing the integral acoustic impedance function, so that the working frequency band of the pipeline and the Helmholtz resonator array can be perfectly matched with the noise elimination frequency band required by a user, and the customization requirement of the user is met.

In one embodiment, the sound absorption coefficient of the pipeline silencer is determined according to the sound absorption coefficientDetermining the corresponding porosity sigma of the pipeline, the wall thickness t of the pipeline, the aperture d of the first micropore and the cannula length l of each Helmholtz resonator when the sound absorption coefficient alpha is maximum in the target frequency band_nVolume V of the resonance chamber_nAnd a radius R of the second micropores_nAnd the impedance matching parameters of the pipeline silencer are obtained.

Drawings

FIG. 1 is a schematic structural diagram of a pipe muffler according to an embodiment of the present application;

FIG. 2 is a schematic structural diagram of a pipeline according to an embodiment of the present application;

FIG. 3 is a schematic structural diagram of a super-structural sound damping unit according to an embodiment of the present application;

FIG. 4 is an enlarged schematic view of the Helmholtz resonator of the embodiment of FIG. 3;

fig. 5 is a schematic diagram illustrating the sound attenuation effect of the pipe silencer according to an embodiment of the present application.

The symbols of the respective elements in the drawings are as follows:

100. the pipe silencer comprises a pipe silencer body 10, a silencer cover shell 101, an air inlet 20, a pipe 201, a first micro hole 30, an ultra-structure silencing unit 31, a Helmholtz resonator 310, a second micro hole 311, a resonator cover shell and a 312 inserting pipe.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. As used herein, the terms "vertical," "horizontal," "left," "right," "upper," "lower," "front," "rear," "circumferential," and the like are based on the orientation or positional relationship shown in the drawings for ease of description and simplicity of description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The traditional pipeline silencer is limited by traditional sound absorption materials, and the sound absorption effect in a low frequency band is not ideal; in addition, the traditional sound absorption materials usually mainly comprise felt and glass fiber, have limited service life, are easy to age, and can enter air through an air duct, so that serious environmental pollution is caused, and even the health of people is harmed.

The metamaterial is an artificial material taking a microstructure as a basic construction unit, has completely different designable physical properties from the traditional material, and the properties of the metamaterial are determined by the properties of microstructure units and the spatial arrangement mode of the microstructure units. The acoustic metamaterial is an acoustic material which is designed completely based on different physical principles and has a special acoustic function.

In view of the above-mentioned drawbacks of the conventional pipeline muffler, as shown in fig. 1, the present application designs a pipeline muffler 100 with high muffling performance in a low frequency band and with a material that is not easily aged by using an acoustic metamaterial. Specifically, the pipe muffler 100 includes a muffler shell 10, a pipe 20, and an ultra sound attenuation unit 30.

The muffler shell 10 has a first side and a second side, the first side is provided with an air inlet 101, and the second side is provided with an air outlet (not shown) corresponding to the air inlet 101. In order to prevent the material from deteriorating to affect the sound-deadening performance, the muffler shell 10 is preferably made of a strong and durable material such as metal. Further, the muffler shell 10 may be a cube, a cuboid, a tetrahedron, or other cubes with different sides, or may be a sphere in some embodiments to meet the installation requirement, which is not limited by the present application.

One end of the pipeline 20 is connected with the air inlet 101, the other end of the pipeline is connected with the air outlet, a first micropore array is arranged on the wall of the pipeline 20, and a space is arranged between every two adjacent first micropores. Specifically, referring to fig. 2, the pipeline 20 is spread to form a rectangular flat plate, and the first micro holes 201 are periodically distributed on the rectangular flat plate at intervals to form a first micro hole array. The pipe 20 is primarily based on thermal viscosity acoustic cancellation of medium and high frequency sound waves (i.e., sound that is rubbed through the pores to cancel sound energy), such as sound waves having a frequency greater than 600 Hz. Further, sound waves with frequencies greater than 1000Hz can be eliminated, and the sound absorption coefficient can be increased with the increase of the sound wave frequency.

The super-structure sound attenuation unit 30 is arranged inside the muffler shell 10, the super-structure sound attenuation unit 30 is arranged outside the pipeline 20 in a surrounding manner along the circumferential direction of the pipeline 20, and a gap is formed between the super-structure sound attenuation unit 30 and the pipeline 20. Specifically, the super sound attenuation units 30 may be arranged in a ring structure around the outer side of the pipeline 20, or a plurality of super sound attenuation units 30 may be arranged in an end-to-end structure around the outer side of the pipeline 20. During silencing, sound waves enter the gap through the first micropores, and then enter the super-structure silencing unit 30 through the gap to perform low-frequency (for example, sound waves with the frequency lower than 800 Hz) silencing. Through using the sound attenuation unit of superstructure to replace traditional sound absorbing material, both can avoid sound absorbing material ageing approximate ventilation air pollution problem, can also eliminate the low frequency range noise better. Further, the super noise elimination unit 30 is preferably made of plastic such as PET, PC, etc., and in other embodiments, the super noise elimination unit may also be made of metal or soft rubber, so that the super noise elimination unit 30 is more robust and less prone to aging.

Specifically, the super-structure sound attenuation unit 30 includes a plurality of basic structure units arranged periodically, and the sound attenuation performance of the super-structure sound attenuation unit 30 is related to the material, the structural characteristics and the spatial arrangement characteristics of the basic structure units. Furthermore, the size of each basic construction unit is in the sub-wavelength order, so that the sound wave can be more effectively regulated and controlled. The super-structure sound attenuation unit 30 may be a one-dimensional layered structure, or a two-dimensional composite structure formed by periodically arranging along two directions, and the structure and size of the basic construction unit may be selected according to the actual sound absorption frequency band requirement and the difficulty of preparation.

Further, the tube 20 has a first acoustic impedance Z_mThe super-structure sound attenuation unit 30 has a second acoustic impedance Z_cFirst acoustic impedance Z_mAnd a second acoustic impedance Z_cThe overall acoustic impedance Z of the pipe muffler 100 is formed by superposition, and within a preset frequency band, the overall acoustic impedance Z and the impedance Z of air₀And (4) matching. When the overall acoustic impedance Z is equal to the impedance Z of air₀When matched, according to the formula of sound absorption coefficientIt can be known that the sound absorption coefficient can reach the maximum value (for example, the sound absorption coefficient can be a value close to 1 such as 0.95-0.999), and the noise elimination effect is optimal at the moment. Specifically, the acoustic impedances of the pipeline 20 and the super-structure muffling unit 30 can be derived according to the impedance theory in acoustics and the specific structure thereof, and in order to realize the maximum efficiency muffling of the pipeline muffler 100, the structural parameters (such as the length, width, height, aperture ratio, aperture size and other parameters) of the pipeline 20 and the super-structure muffling unit 30 can be calculated and adjusted through operation software, and the integral acoustic impedance Z and the air impedance Z of the pipeline muffler 100 are selected₀The parameters matched are used as actual manufacturing parameters of the pipe muffler 100.

In the pipe silencer 100, the overall acoustic impedance of the pipe 20 and the super-structure silencing unit 30 is matched with the acoustic impedance of air, so that the pipe silencer 100 has the maximum sound absorption coefficient and a better sound absorption effect; meanwhile, the super-structure sound attenuation unit is adopted to replace traditional sound absorption materials such as glass wool, cotton felt and the like in the traditional sound absorber, so that the sound absorption performance of the pipeline sound absorber 100 in a low frequency band can be enhanced, and the traditional sound absorption materials are prevented from aging to pollute the environment; in addition, the pipeline muffler 100 can reasonably adjust the structural parameters of the pipeline 20 and the super-structure muffling unit 30 according to the muffling frequency band required by the user, so that the working frequency band is perfectly matched with the user requirement.

In the exemplary embodiment, the super sound attenuation unit 30 has a plurality. Taking fig. 3 as an example, there are 4 super-structure sound attenuation units 30, each super-structure sound attenuation unit 30 is plate-shaped, the side edges of two adjacent super-structure sound attenuation units 30 are connected in sequence to form a structure in the shape of a Chinese character kou, and the pipeline 20 is located inside the Chinese character kou. When the number of the super-structure noise elimination units 30 is multiple, the plurality of super-structure noise elimination units 30 can be simultaneously prepared by using a small-volume mold or a 3D printing model, and then the large-volume super-structure noise elimination unit is prepared, which is beneficial to reducing the preparation difficulty and the preparation cost of the pipeline muffler 100.

In an exemplary embodiment, with continued reference to fig. 3, the ultra sound attenuation unit 30 includes an array of helmholtz resonators 31, each helmholtz resonator 31 has an open side and a closed side opposite to each other, the open side faces the pipe 20 and is opened with a second micro-hole 310, the second micro-hole 310 is communicated with the gap, the open sides of the helmholtz resonators 31 are located in the same plane, and sound waves enter the helmholtz resonators 31 through the second micro-hole 310. Specifically, when there is only one sound attenuation suppressing unit 30, the opening sides of the helmholtz resonators 31 may be located in the same curved plane, and when there are a plurality of the sound attenuation suppressing units 30, the opening sides of the helmholtz resonators 31 may be located in the same plane. When the frequency of the incident sound wave is equal to the natural vibration frequency of the air column in the Helmholtz resonator, resonance phenomenon can be generated, the amplitude of the air column is maximum at the moment, and the corresponding sound energy dissipation is also maximum, so that the aim of eliminating noise is fulfilledIn (1). Further, since the sound waves enter the respective helmholtz resonators 31 at the same time, it is presumed that the helmholtz resonators 31 are disposed in parallel on the transmission path of the sound waves, and therefore the second acoustic impedance Z is a sound impedance_cThe parallel equation of the impedance is satisfied:wherein Z_nThe surface acoustic impedance of the helmholtz resonator 31 is shown, and n is the ordinal number of the helmholtz resonator.

In an exemplary embodiment, as shown in fig. 4, the helmholtz resonator 31 includes: a resonator housing 311 having a third side and a fourth side opposite to each other, the third side facing the duct 20 and opened with a second micro-hole 310; and a insertion tube 312 disposed inside the resonator housing, connected to the third side and extending to the fourth side, the insertion tube 312 being coaxial with the second micro-hole 310, and the aperture of the insertion tube 312 being equal to the aperture of the second micro-hole 310. Preferably, the length of the cannula 312 is less than the wavelength of the incident sound waves. Specifically, the column of air in the insert 312 and the cavity inside the resonator housing 311 may together form a resonance cavity of the helmholtz resonator 31.

Further, when the Helmholtz resonator is a square body (including a rectangular parallelepiped and a square), the surface acoustic impedance Z of the Helmholtz resonator_nSatisfies the following conditions:

where A represents the area of the entire third side (i.e., the area of the entire third side including the wall thickness of the resonator housing 311 and the second keyhole opening), S_aDenotes an opening area of the second micro-hole 310, L denotes a length of the cannula 312, L denotes a vertical distance from the inner surface of the third side to the inner surface of the fourth side, ρ_cc、c_ccAnd k_ccRespectively representing the density, speed of sound and wave number, k, of the air in the Helmholtz resonator 31_ca、Ψ_vaAnd Ψ_haRespectively represents wave number, viscosity term and thermal term of the cannula under narrow acoustics, gamma represents specific heat capacity of air, and delta_ΩRepresenting an end-of-acoustic-mass correction term,τ_Ωdenotes a correction factor, S_cDenotes an area of the inner surface of the fourth side, ω denotes an angular frequency, η denotes a viscosity coefficient of air, ρ₀Denotes the density of air under natural conditions, c₀Representing the speed of sound propagation in the ambient air. Further, the volume of the resonance cavity of the Helmholtz resonator can be increased by S_cAnd L is obtained by calculation.

Through the above formula, the depth, the second micropore aperture and the cannula length of each helmholtz resonator 31 can be optimized, so that the parameter that can realize the matching of the overall impedance and the air impedance of the pipe muffler 100 is found. For example, as can be seen from fig. 3, the sizes of the second micro-holes in each helmholtz resonator 31 and the lengths of the insertion tubes are different, which is determined by the impedance matching parameters of each helmholtz resonator 31 according to the above formula.

In an exemplary embodiment, the first acoustic impedance Z_mSatisfies the following conditions:

wherein the content of the first and second substances,eta represents the viscosity coefficient of air, rho₀Denotes the density of air under natural conditions, c₀Represents the propagation velocity of sound in the outside air, σ represents the porosity of the pipe 20, ω represents the angular frequency, t represents the wall thickness of the pipe 20, and d represents the pore diameter of the first minute hole 201.

Through the above formula, the pore diameter and porosity of the first micropores 201 and the wall thickness of the pipe 20 can be obtained through optimization, wherein the pore diameter of each first micropore 201 can be equal, thereby facilitating the preparation of the pipe 20.

The present application further provides a pipe silencer device comprising a plurality of pipe silencers as described above in series.

Above-mentioned pipeline noise eliminator can directly regard as gas transmission's pipeline device after establishing ties to can effectively eliminate the noise of business turn over wind gap department in gas transmission, thereby promote people's life travelling comfort, the environmental pollution that still can avoid traditional sound absorbing material to age to lead to simultaneously guarantees that the user is healthy.

As shown in fig. 1 to 4, the pipe silencer 100 includes a silencer housing 10 having a first side and a second side, the first side being provided with an air inlet 101, and the second side being provided with an air outlet corresponding to the air inlet 101; one end of the pipeline 20 is connected with the air inlet 101, the other end of the pipeline is connected with the air outlet, and a first micropore array is formed in the wall of the pipeline 20; and a helmholtz resonator array (i.e., an ultra sound attenuation unit 30) which is arranged inside the muffler shell 10, is arranged around the outside of the pipe 20 along the circumferential direction of the pipe 20, and has a gap with the pipe 20; the helmholtz resonator includes a resonator housing 311 having a third side and a fourth side disposed opposite to each other, the third side facing the duct 20 and opened with a second micro hole 310; and a cannula 312 disposed inside the resonator housing 311, connected to the third side and extending to the fourth side, the cannula 312 being coaxial with the second micro-hole 310, and the aperture of the cannula 312 being equal to the aperture of the second micro-hole 310, preferably, the length of the cannula 312 is smaller than the wavelength of the incident sound wave;

the preparation method comprises the following steps:

s1, obtaining a first acoustic impedance function Z of the pipeline 20_m(σ, t, d), wherein σ represents the porosity of the tube 20, t represents the wall thickness of the tube 20, and d represents the pore diameter of the first micropores 201;

further, based on the thermal viscous acoustic and the acoustic vibration, the first acoustic impedance function may be:

wherein the content of the first and second substances,eta represents the viscosity coefficient of air, rho₀Denotes the density of air under natural conditions, c₀Represent sound atPropagation velocity in the outside air, σ represents porosity of the pipe 20, ω represents angular frequency, t represents wall thickness of the pipe 20, and d represents pore diameter of the first micropores 201;

s2, obtaining a second acoustic impedance function Z of the Helmholtz resonator array_c(l_n，V_n，R_nN) in which l_nIndicates the length, V, of the cannula 312_nIndicating the volume of the resonance chamber, R, in the Helmholtz resonator 31_nDenotes a radius of the second micropore 310, and n denotes an ordinal number of the helmholtz resonator 31;

further, when the helmholtz resonator is a square, the second acoustic impedance function may be:

wherein A represents the area of the entire third side, S_aDenotes an opening area of the second micro-hole 310, L denotes a length of the insertion tube 312, L denotes a vertical distance from the inner surface of the third side to the inner surface of the fourth side, ρ_cc、c_ccAnd k_ccRespectively representing the density, speed of sound and wave number, k, of the air in the Helmholtz resonator 31_ca、Ψ_vaAnd Ψ_haRespectively, the wavenumber, viscosity and thermal terms of the cannula 312 at narrow acoustics, gamma the specific heat capacity of air, and delta_ΩRepresenting an acoustic mass end correction term, τ_ΩDenotes a correction factor, S_cRepresenting the area of the inner surface of the fourth side. Further, the volume V of the resonance cavity_nThis can be calculated by measuring the wall thickness of the resonator housing 311 and then differencing based on volume, or by measuring the area of the bottom surface of the cavity and combining the depth of the cavity (i.e., the vertical distance L from the third side inner surface to the fourth side inner surface) (V)_n＝S_cL), the particular skilled person can select it according to the actual situation.

S3 finding the first acoustic impedance function Z_m(σ, t, d) and the second acoustic impedance function Z_c(l_n，V_n，R_nN) obtaining the entirety of the pipe mufflerAcoustic impedance function Z (σ, t, d, l)_n，V_n，R_nN), wherein Z (σ, t, d, l)_n，V_n，R_n，n)＝Z_m(σ，t，d)+Z_c(l_n，V_n，R_n，n)

S4, providing a target frequency band;

s5, for the target frequency band, according to the integral acoustic impedance function Z (sigma, t, d, l)_n，V_n，R_nN) determining the overall acoustic impedance Z and the impedance Z of air₀When matched, the porosity σ of the tube 20, the wall thickness t of the tube 20, the pore diameter d of the first micropores 201, and the length l of the insertion tube 312 of each Helmholtz resonator 31_nVolume V of the resonance chamber_nAnd radius R of second micro-hole 310_n；

S6, mixing sigma, t, d and l_n、V_n、R_nRespectively, to the duct 20 and to the array of helmholtz resonators.

The preparation method of the pipeline silencer can prepare the pipeline silencer 100 with good low-frequency sound absorption effect; meanwhile, structural parameters of the pipeline and the Helmholtz resonator array when impedance matching is met can be determined according to the target frequency band by utilizing the integral acoustic impedance function, so that the working frequency band of the pipeline and the Helmholtz resonator array can be perfectly matched with the noise elimination frequency band required by a user, and the customization requirement of the user is met. It should be noted that, the above steps S1 to S4 do not have a sequential relationship, and the skilled person can adjust the sequence according to actual requirements.

In an exemplary embodiment, determining when the overall acoustic impedance Z is equal to the impedance Z of air₀When matched, the sound absorption coefficient of the pipeline silencer 100 can be adjustedDetermining the porosity σ of the corresponding pipe 20, the wall thickness t of the pipe 20, the aperture d of the first micropore 201, and the cannula length l of each Helmholtz resonator 31 when the sound absorption coefficient alpha is maximum within the target frequency band_nVolume V of the resonance chamber_nAnd radius R of second micro-hole 310_nIs an impedance matching parameter of the pipe muffler 100.Wherein Z is₀＝ρ₀c₀. It can be seen that due to Z₀Is real, so that when the integral acoustic impedance Z is optimized, the real part Z of Z can be made_aAnd Z₀The ratio of (A) approaches 1, and the imaginary part Z of Z_bThe direction optimization approaching 0 also obtains the maximum value of the sound absorption coefficient α of the pipe muffler 100.

Further, fig. 5 shows a schematic diagram of the sound attenuation effect of the pipe silencer 100 according to an embodiment of the present application. Specifically, in fig. 5, the horizontal axis represents the frequency band of the incident sound wave, and the vertical axis represents the transmission loss of the sound wave. It can be seen that the pipeline silencer 100 of the present application has a plurality of transmission loss peaks at 300Hz to 800Hz, and the sound wave transmission loss corresponding to each transmission loss peak is far greater than the transmission loss of the traditional sound-absorbing cotton type pipeline silencer, so that it can be considered that the low-frequency silencing effect of the pipeline silencer 100 of the present application is obviously superior to that of the traditional pipeline silencer.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.