CN117789690A - Side suction pipeline muffler structure based on acoustic black hole effect and application - Google Patents
Side suction pipeline muffler structure based on acoustic black hole effect and application Download PDFInfo
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- CN117789690A CN117789690A CN202311838603.4A CN202311838603A CN117789690A CN 117789690 A CN117789690 A CN 117789690A CN 202311838603 A CN202311838603 A CN 202311838603A CN 117789690 A CN117789690 A CN 117789690A
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- 239000002184 metal Substances 0.000 claims abstract description 50
- 230000009467 reduction Effects 0.000 claims abstract description 46
- 239000000463 material Substances 0.000 claims description 9
- 230000003584 silencer Effects 0.000 claims description 5
- 239000011229 interlayer Substances 0.000 claims 1
- 238000009428 plumbing Methods 0.000 claims 1
- 230000008859 change Effects 0.000 abstract description 5
- 238000013016 damping Methods 0.000 abstract description 3
- 239000011148 porous material Substances 0.000 abstract description 2
- 238000010521 absorption reaction Methods 0.000 description 4
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- JJWKPURADFRFRB-UHFFFAOYSA-N carbonyl sulfide Chemical compound O=C=S JJWKPURADFRFRB-UHFFFAOYSA-N 0.000 description 1
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- Exhaust Silencers (AREA)
Abstract
The invention discloses a bypass pipeline muffler structure based on an acoustic black hole effect and application thereof, and the bypass pipeline muffler structure comprises a cylindrical muffler pipeline with larger inner diameter, wherein the cylindrical muffler pipeline is connected with a noise reduction main pipeline, a plurality of metal baffles are radially distributed along the noise reduction main pipeline on the inner walls of the two sides of the cylindrical muffler pipeline, the widths of the metal baffles gradually expand from the minimum inner diameter of the cylindrical muffler pipeline to the maximum inner diameter of the cylindrical muffler pipeline, the connecting surfaces of the extending ends of the metal baffles on the two sides of the noise reduction main pipeline form symmetrical arc surfaces which are not contacted with each other, and the symmetrical arc surfaces are axisymmetrical. The sound waves propagate through the main pipe to the acoustic black hole member, where their energy will be concentrated into the muffler due to the acoustic black hole effect and dissipated by damping of the porous material or the air itself. The structure does not change the inner diameter of the main pipeline, can not reduce the flow velocity of the medium in the main pipeline, can not generate new flow noise, and can achieve the aim of better noise reduction.
Description
Technical Field
The invention relates to the technical field of pipeline noise reduction and sound propagation, in particular to a bypass pipeline muffler structure based on an acoustic black hole effect and application thereof.
Background
In daily life, agricultural tools such as vehicles with tail pipes, tractors and the like, and appliances such as engines with exhaust pipes and the like, when exhaust gas/exhaust gas is discharged, noise caused by airflow is usually accompanied in an exhaust pipeline, and the broadband noise has excessive intensity, so that the pipeline is easily damaged, and on the one hand, larger noise harm is caused to operators or personnel nearby the appliances. In recent years, the acoustic black hole structure provided in the acoustic field has the characteristics of light weight, high damping, high frequency dispersion, high energy aggregation and the like, and has great application potential in the fields of noise control, acoustic wave regulation, high-energy recovery and the like.
The acoustic black hole concept can be analogous to the black hole concept in celestial physics. Black hole in celestial physics refers to a singular point with infinite density, infinite space-time curvature, infinite small volume and infinite heat, and can engulf all light rays and any substances in the vicinity of a cosmic area. The concept of acoustic black holes can be likened, the acoustic black hole effect being: the phase velocity and the group velocity of the sound wave are gradually reduced to approach zero by performing power law adjustment on the pipe diameter of the pipe and controlling the impedance of the inner wall of the pipe, so that the sound wave generates a sound wave gathering effect at the tail end of the pipe, and a high energy density area is formed.
The current research on the acoustic black hole mainly comprises a one-dimensional structure and a two-dimensional structure, and the pipe diameter change rule of the ideal acoustic black hole structure obeys the power rate distribution. Ideally, the pipe diameter of the acoustic black hole structure is reduced to zero along the direction of the center of the pipe shaft to the periphery.
However, for the one-dimensional and two-dimensional acoustic black hole structures, the pipe diameter of the main pipeline needs to be reduced, for example, a baffle plate is added, other materials are filled, so that the complexity of pipeline processing is increased, the processing cost is increased, meanwhile, the inner diameter of the pipeline is reduced, the flow rate of fluid is greatly reduced, meanwhile, the passing fluid can excite new noise, the practicability of the pipeline is seriously influenced, and the application and popularization of the acoustic black hole are hindered.
Therefore, in the noise reduction process of the fluid pipeline, it is very important to design a muffler based on the acoustic black hole effect, wherein the muffler does not damage the original pipe diameter.
Disclosure of Invention
In order to solve the defects in the prior art, the invention aims to provide the bypass pipeline muffler based on the acoustic black hole effect, and the bypass pipeline muffler component based on the acoustic black hole effect is applied between two sections of main pipelines, so that the purpose of better noise reduction is achieved while the pipe diameter of the main pipelines is not reduced.
The invention is realized by the following technical scheme.
The invention provides a pipeline bypass muffler structure based on an acoustic black hole effect, which comprises a columnar muffler pipeline coaxially connected with a noise reduction main pipeline, wherein the inner diameter of the columnar muffler pipeline is larger than that of the noise reduction main pipeline; the inner walls of the two sides of the columnar muffler pipeline are provided with a plurality of metal baffles which are radially distributed along the noise reduction main pipeline, the widths of the metal baffles gradually expand from the minimum inner diameter to the maximum inner diameter of the columnar muffler pipeline, the connecting surfaces of the extending ends of the metal baffles on the two sides in the noise reduction main pipeline form symmetrical arc surfaces which are not contacted with each other, and the symmetrical arc surfaces are axisymmetrical.
Preferably, the inner diameter of the columnar muffler pipe is 2 times that of the noise reduction main pipe.
Preferably, each metal baffle is a thin column shell structure with the same central axis as the column-shaped muffler pipeline and the noise reduction main pipeline.
Preferably, a plurality of metal baffles are rigidly connected to the inner wall of the cylindrical muffler pipe.
Preferably, adjacent metal baffles are equidistantly distributed on two sides of the inner wall of the cylindrical muffler pipeline and are not contacted with each other.
Preferably, the spacing between the longest metal baffles of the symmetrical arc surfaces is the narrowest gap in the cylindrical muffler pipe with the acoustic black hole effect, and the narrowest gap is not more than 1/10 of the length of the cylindrical muffler pipe.
Preferably, the columnar muffler pipeline is the same as the noise reduction main pipeline in material, and the metal baffle is the same as the noise reduction main pipeline in material.
Due to the adoption of the technical scheme, the invention has the following beneficial effects:
1. according to the side straw silencer structure based on the acoustic black hole effect, the noise reduction main pipeline is directly spliced with the main pipeline on the main pipeline, the noise reduction main pipeline is formed by utilizing the plurality of metal baffles, sound waves are transmitted to the acoustic black hole component through the main pipeline by utilizing the acoustic black hole effect, and plane wave energy in the main pipeline is concentrated into the noise reduction main pipeline due to the acoustic black hole effect and is dissipated through damping of porous materials or air. The energy of noise in the pipeline is effectively dissipated.
2. The widths of a plurality of metal baffles of the columnar muffler pipeline are gradually expanded along with the distribution of the inner diameter of the columnar muffler, symmetrical arc surfaces are formed at the extending ends and are not contacted with each other, plane wave energy in the main pipeline is concentrated into an acoustic black hole structure formed by the symmetrically distributed metal baffles, and after sound waves pass through the acoustic black hole muffler, propagation loss is high, so that stable and broadband high sound absorption performance is realized.
3. The structure only needs to replace a part of the main pipeline, is convenient to detach, does not change the inner diameter of the main pipeline, does not reduce the flow velocity of the medium in the main pipeline, does not generate new flow noise, and can achieve the aim of reducing noise better. The acoustic black hole structure has wide application prospect in a series of pipeline structures forming noise due to medium flow, such as industrial pipeline equipment, engine equipment, gas emission equipment and the like.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate and do not limit the invention, and together with the description serve to explain the principle of the invention:
FIG. 1 is a schematic perspective view of a noise reducing structure of the present invention attached to a main pipe;
FIG. 2 is a schematic view of a noise reducing structure of the present invention attached to a main pipe in an axially cut-away perspective;
FIG. 3 is a schematic view of an acoustic black hole member in a noise reduction structure of the present invention;
FIG. 4 is a schematic cross-sectional view of an acoustic black hole member in a noise reducing structure of the present invention;
FIG. 5 is a graph comparing the transmission loss of noise in a main pipe after passing through a noise reduction structure of the present invention and a cavity without an acoustic black hole member;
FIG. 6 is a graph comparing the transmission loss of noise in a main pipe after passing through the noise reducing structure of the present invention and the main pipe of the same length without any noise reducing measures applied;
the reference numerals in the figures are respectively: 1-a noise reduction main body pipe; 2-a cylindrical muffler pipe; 3-metal baffle.
Detailed Description
The present invention will now be described in detail with reference to the drawings and the specific embodiments thereof, wherein the exemplary embodiments and descriptions of the present invention are provided for illustration of the invention and are not intended to be limiting.
As shown in fig. 1, an embodiment of the present invention provides a bypass muffler structure based on an acoustic black hole effect, including: the columnar muffler pipe 2 coaxially connected to the noise reduction main pipe 1, the columnar muffler pipe 2 having an inner diameter larger than the noise reduction main pipe 1, and in this embodiment, the columnar muffler pipe has an inner diameter 2 times that of the noise reduction main pipe.
As shown in fig. 2, the inner walls of the two sides of the cylindrical muffler pipe 2 are provided with a plurality of metal baffles 3 radially distributed along the noise reduction main pipe 1, the widths of the plurality of metal baffles 3 from the minimum inner diameter of the cylindrical muffler pipe 2 to the maximum inner diameter of the cylindrical muffler pipe 2 are gradually widened in sequence, the connecting surfaces of the extending ends of the plurality of metal baffles on the two sides in the noise reduction main pipe form symmetrical arc surfaces which are not contacted with each other, and the symmetrical arc surfaces are axisymmetric to form an acoustic black hole component with a noise reduction structure.
As shown in fig. 2, adjacent metal baffles are equidistantly distributed on two sides of the inner wall of the cylindrical muffler pipe 2 and are not in contact with each other. The thin metal baffle is rigidly connected to the inner wall of the cylindrical muffler pipe 2.
As shown in fig. 3, each metal baffle 3 has a thin cylindrical shell structure concentric with the cylindrical muffler pipe 2 and the noise reduction main pipe 1. In this structure, the pitches of the adjacent metal shutters 3 of each layer are the same, and the pitches are not smaller than the thickness of the metal shutters 3. In one embodiment, the thickness of each metal baffle 3 is not more than 5mm, but when the number of metal baffles 3 is large, it is assumed that the inner diameter of the noise reduction main pipe 1 is r 0 The inner diameter of the columnar muffler pipeline 2 is R 0 And the number of the metal baffles 3 is N, and the thickness H of the metal baffles 3 is calculated according to the following formula:
in one embodiment, the noise reduction body conduit 1 has an inner diameter r 0 Is 100mm, and the inner diameter R of the columnar muffler pipeline 2 0 200mm, and 25 metal baffles 3, the thickness H of the metal baffles 3 should not exceed 2mm.
In this structure, the spacing between the metal baffles 3 with the longest symmetrical arcuate surfaces (the narrowest gap for the black hole effect) is not more than 1/10 of the length of the muffler 2. In one embodiment, the length of the cylindrical muffler pipe 2 is 100mm, and then the spacing of the metal baffles 3 with the longest symmetrical arc surfaces (the narrowest gap of the black hole effect) is less than 10mm.
As shown in fig. 4, the change rule of the width d of the metal baffle plate of the acoustic black hole member along with the inner diameter of the cylindrical muffler pipe is:
d(r)＝d c +ε(R 0 -r 0 ) m
wherein r is 0 For reducing the inner diameter of the main pipeline, R 0 The inner diameter of the pipeline of the columnar muffler is; d, d c Subtracting the maximum width of the metal baffle plate from the half width of the columnar muffler pipeline, d c Not less than 0; epsilon is the slope of the section, epsilon is more than 0; m is the acoustic black hole order, and m is more than or equal to 2.
In this embodiment, the inner diameter r of the noise reduction main pipe 1 is selected 0 The inner diameter r of the cylindrical muffler pipe 2 is 0.2m, the length of the cylindrical muffler pipe is 0.1m, r 0 0.05m, R is 0.1m, d c 0.01m, epsilon of 18 and m of 2. The width d of the thin metal barrier is 0.0324m (3.24 mm).
According to the invention, the columnar muffler pipeline 2 is made of the same material as the noise reduction main pipeline 1, and the metal baffle 3 is made of the same material as the noise reduction main pipeline 1.
The working principle of the invention is as follows: on the main pipeline, the muffler utilizes the acoustic black hole effect to concentrate the plane wave energy in the main pipeline into the muffler, and the energy of noise in the pipeline is effectively dissipated by utilizing the acoustic black hole effect. In addition, this structure only needs the replacement of a part of trunk line, and it is convenient to dismantle, can not change the internal diameter of trunk line, can not reduce the velocity of flow of medium in the trunk line, can not produce new stream noise, can reach the purpose of making an uproar falls betterly.
And establishing a simulation model by using Comsol musithics 6.1 finite element simulation software, and optimizing parameters of the acoustic black hole component in the vibration reduction structure.
Solid-mechanical simulations were performed using COMSOL multiphysics6.1 finite element simulation software to find the optimal dimensions. The COMSOL multiphysics6.1 simulation model diagram is shown in fig. 1, and during simulation, the built model size inner diameter of the noise reduction main pipeline 1 is 0.1m, the length is 1m, the inner diameter of the columnar silencer pipeline 2 is 0.2m, and the length is 0.1m.
Furthermore, the invention provides a design method of an acoustic black hole component in a side suction pipe silencer structure based on an acoustic black hole, which comprises the following steps:
and finally, selecting the inner diameter of the columnar muffler pipeline to be 2 times of the inner diameter of the noise reduction main pipeline 1 by comparing transmission loss comparison graphs of the cavities of the different muffler pipelines and the inner diameter of the main pipeline.
The number of units of the metal baffles constituting the acoustic black hole member 3 was selected to be 100 by comparing the transmission loss of sound waves through the muffler when the acoustic black hole member was constituted by different numbers of thin metal baffles.
In this embodiment, the material of the cylindrical muffler pipe 2 is the same as that of the noise reduction main pipe 1, and the material of the metal baffle 3 is the same as that of the noise reduction main pipe 1.
2. Model calculation result analysis
As can be seen from FIG. 5, in the embodiment of the present invention, the propagation loss (i.e., sound absorption performance) of the sound wave in the pipeline through the bypass pipeline muffler based on the acoustic black hole effect is much higher than that of the expansion pipe muffler without the acoustic black hole structure within 500-1200Hz, which is higher by 35dB at most, and higher by 8dB on average. Initial frequency of the acoustic black hole structureThe muffler begins to exhibit stable, broadband, high suction near the start frequencyAcoustic performance. Compared with a expansion pipe muffler with a silent black hole structure, the propagation loss of sound waves after passing through the acoustic black hole muffler is stabilized at 10dB, which is higher by 13dB at most and higher by 11dB on average at 1650Hz-3500 Hz.
As can be seen from FIG. 6, in the embodiment of the present invention, the propagation loss (i.e., sound absorption performance) of sound waves in the pipeline through the bypass pipeline muffler based on the acoustic black hole effect is much higher than that of the pipeline with the same length without the muffler within 0-3500Hz, which is higher by 42dB at most, and higher by 18dB on average. The muffler begins to exhibit stable, broadband, high sound absorption performance near the starting frequency. At 1500Hz-3500Hz, compared with the pipeline with the same length without the muffler, the propagation loss of the sound wave after passing through the acoustic black hole muffler is stably 13dB higher, at most 20dB higher, and on average 15dB higher.
The invention can be applied to main pipelines of medium flows of industrial pipeline equipment, engine equipment and gas emission equipment, the muffler pipeline utilizes the acoustic black hole effect to concentrate plane wave energy in the main pipeline into the muffler, and the acoustic black hole effect can be utilized to effectively dissipate noise energy in the pipeline, so that the inner diameter of the main pipeline is not changed, the flow velocity of the medium in the main pipeline is not reduced, new flow noise is not generated, and the aim of better noise reduction can be achieved.
The invention is not limited to the above embodiments, and based on the technical solution disclosed in the invention, a person skilled in the art may make some substitutions and modifications to some technical features thereof without creative effort according to the technical content disclosed, and all the substitutions and modifications are within the protection scope of the invention.
Claims (10)
1. The bypass pipeline muffler structure based on the acoustic black hole effect is characterized by comprising a columnar muffler pipeline coaxially connected with a noise reduction main pipeline, wherein the inner diameter of the columnar muffler pipeline is larger than that of the noise reduction main pipeline; the inner walls of the two sides of the columnar muffler pipeline are provided with a plurality of metal baffles which are radially distributed along the noise reduction main pipeline, the widths of the metal baffles gradually expand from the minimum inner diameter to the maximum inner diameter of the columnar muffler pipeline, the connecting surfaces of the extending ends of the metal baffles on the two sides in the noise reduction main pipeline form symmetrical arc surfaces which are not contacted with each other, and the symmetrical arc surfaces are axisymmetrical.
2. The bypass duct muffler structure based on the acoustic black hole effect according to claim 1, wherein the inner diameter of the cylindrical muffler duct is 2 times the inner diameter of the noise reduction main duct.
3. The bypass duct muffler structure based on the acoustic black hole effect according to claim 1, wherein each metal baffle is a thin cylindrical shell structure concentric with the cylindrical muffler pipe and the noise reduction main pipe.
4. The bypass duct muffler structure based on the acoustic black hole effect according to claim 1, wherein a plurality of metal baffles are rigidly connected to the inner wall of the cylindrical muffler duct.
5. The bypass-duct muffler structure based on the acoustic black hole effect according to claim 1, wherein the inter-layer adjacent metal baffles are equally spaced on both sides of the inner wall of the cylindrical muffler duct and are not in contact with each other.
6. The bypass duct muffler structure based on the acoustic black hole effect as claimed in claim 1, wherein the metal baffle thickness H is calculated as follows:
wherein r is 0 For reducing the inner diameter of the main pipeline, R 0 The inner diameter of the pipeline of the columnar silencer is the inner diameter of the pipeline of the columnar silencer, and N is the number of metal baffles.
7. The bypass duct muffler structure based on the acoustic black hole effect as claimed in claim 1, wherein the width d (r) of the plurality of metal baffles is distributed along the inner diameter of the cylindrical muffler duct to satisfy the following formula:
d(r)＝d c +ε(R 0 -r 0 ) m
wherein r is 0 For reducing the inner diameter of the main pipeline, R 0 The inner diameter of the pipeline of the columnar muffler is; d, d c Subtracting the maximum width of the metal baffle plate from half of the width of the cylindrical muffler pipeline, and d c Not less than 0; epsilon is the slope of the section and epsilon>0; m is the acoustic black hole order, and m is more than or equal to 2.
8. The bypass duct muffler structure based on the acoustic black hole effect according to claim 1, wherein the spacing between the longest metal baffles of the symmetrical arcuate surfaces is the narrowest gap in the cylindrical muffler duct of the acoustic black hole effect, the narrowest gap being no more than 1/10 of the length of the cylindrical muffler duct.
9. The bypass duct muffler structure based on the acoustic black hole effect according to claim 1, wherein the columnar muffler duct is made of the same material as the noise reduction main duct, and the metal baffle is made of the same material as the noise reduction main duct.
10. Use of a bypass duct muffler structure based on the acoustic black hole effect as claimed in any one of claims 1 to 9 in medium flow ducts of industrial plumbing, engine equipment, gas exhaust equipment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311838603.4A CN117789690A (en) | 2023-12-28 | 2023-12-28 | Side suction pipeline muffler structure based on acoustic black hole effect and application |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311838603.4A CN117789690A (en) | 2023-12-28 | 2023-12-28 | Side suction pipeline muffler structure based on acoustic black hole effect and application |
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| Publication Number | Publication Date |
|---|---|
| CN117789690A true CN117789690A (en) | 2024-03-29 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311838603.4A Pending CN117789690A (en) | 2023-12-28 | 2023-12-28 | Side suction pipeline muffler structure based on acoustic black hole effect and application |
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| Country | Link |
|---|---|
| CN (1) | CN117789690A (en) |
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2023
- 2023-12-28 CN CN202311838603.4A patent/CN117789690A/en active Pending
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