Branch pipe-perforated screen composite sound absorption structure for flow pipe noise reduction

Abstract

The invention belongs to the technical field of noise control of pipelines with high-speed airflow, and particularly discloses a bypass pipe-perforated screen composite sound absorption structure for flow pipe noise reduction, the structure comprises a main pipeline, a bypass pipe silencer and a perforated screen, the bypass pipe silencer is arranged on the side wall surface of the main pipeline, and the perforated screen is arranged on the side wall surface of the main pipeline. The side branch pipe silencers are fixedly connected with the main pipeline through fixing bolts; and the perforated screen is arranged at the interface of the side branch pipe silencer and the main pipeline. By the adoption of the bypass branch pipe-perforated screen composite sound absorption structure for noise reduction of the flow pipe, the flow separation phenomenon at an inlet and an outlet of the bypass branch pipe can be restrained, the flow field quality of a main pipeline is improved, and the noise reduction effect of the bypass branch pipe in the flow pipe cannot be greatly influenced; in addition, the structure is simple, the perforated screen does not need to be specially designed, the perforated screen is not limited by the shapes of the main pipeline and the branch pipes, and the perforated screen has good application value in the field of flow pipe noise reduction.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pipeline noise control in the presence of high-speed airflow, and particularly relates to a side branch pipe-perforated screen composite sound absorption structure for flow pipe noise reduction. BACKGROUND

[0002] Noise not only harms human physiology and psychology, but also causes irreversible damage to the system under certain working conditions. As a typical resistive muffler, the side branch pipe has shown great application potential in the field of pipeline noise control due to its superior single-frequency noise reduction performance. The side branch pipe uses the superposition and interference of sound waves to control noise at a specific frequency, so it also belongs to a kind of resistive muffler. After the sound wave passes through the side branch pipe, a phase difference is generated at the intersection with the sound wave of the main pipe. When the phase difference of the two superimposed sound waves is 180°, the phase will be canceled, thereby suppressing the propagation of noise at a specific frequency, such as side branch resonators, interference mufflers, etc. Some mufflers can also be combined with structures such as designed perforated screens to form impedance combined mufflers, such as Helmholtz resonators, etc.

[0003] When there is high-speed airflow in the main pipe, flow separation occurs at the interface between the side branch pipe and the main pipe, which significantly reduces the noise control performance of the system. In addition, the flow separation phenomenon also destroys the stability of air flow in the main pipe, which is unacceptable for related fields such as aircraft engines and wind tunnels that pursue flow field quality. The traditional method uses a perforated screen as the interface between the side branch pipe and the main pipe to suppress flow separation, but the high acoustic resistance of the perforated screen significantly affects the sound absorption characteristics of the side branch pipe, not only reducing the single-frequency noise reduction performance of the system, but also causing the noise reduction frequency to shift.

[0004] Therefore, there is a need in the art to develop a flow pipe noise reduction and sound absorption structure to effectively solve the above problems. SUMMARY

[0005] The present application aims to provide a side branch pipe-perforated screen composite sound absorption structure for flow pipe noise reduction, which can not only suppress the flow separation phenomenon at the inlet and outlet of the side branch pipe and improve the flow field quality of the main pipe, but also has little effect on the noise reduction effect of the side branch pipe in the flow pipe. Therefore, when designing noise reduction for a specific frequency, only the perforated screen needs to be added after the design of the muffler structure is completed, and the influence of the perforated screen on the sound absorption characteristics can be ignored, greatly simplifying the design process. In addition, the structure is simple, does not require special design of the perforated screen, and is not limited by the shape of the main pipe and the side branch pipe, and has good application value in the field of flow pipe noise reduction.

[0006] In order to achieve the above object, the application provides a kind of side branch pipe-perforated screen composite sound absorption structure for flow pipe noise reduction, including main pipeline, side branch pipe muffler, perforated screen, the side branch pipe muffler is arranged in the side wall of main pipeline, and the side branch pipe muffler is fixed between main pipeline by fixed bolt connection;Perforated screen is arranged at the interface of side branch pipe muffler and main pipeline.

[0007] Preferably, the type of side branch pipe muffler has no specific requirements, including side branch resonator, helmholtz resonator, interference muffler, etc.;The configuration of the side branch pipe muffler has no specific requirements, including conventional configuration, segmented coiled type, frequency modulation structure, etc.

[0008] Preferably, the perforated screen is tightly attached to the main pipeline and the side branch pipe muffler by welding, pasting, bolt fixing and the like.

[0009] Preferably, the perforated screen is composed of a wire mesh and a perforated plate;The perforated plate is arranged between the side branch pipe muffler and the wire mesh, and the wire mesh is flush with the inner wall of the main pipeline. The side branch pipe muffler and the perforated plate, and the perforated plate and the wire mesh are tightly attached by welding, pasting, bolt fixing and the like.

[0010] Preferably, the material of the wire mesh has no specific limitation, which is selected according to the air flow intensity in the main pipeline and the use environment, including stainless steel, iron, titanium, nickel, copper and other alloy materials. The wire diameter and mesh number of the wire mesh have no specific limitation, which is selected according to the air flow rate in the main pipeline.

[0011] When the air flow rate in the main pipeline is low, a wire mesh with smaller wire diameter and mesh number can be selected to improve the acoustic performance. With the increase of the air flow rate in the main pipeline, a wire mesh with larger wire diameter and mesh number should be selected to avoid the destruction of the wire mesh structure and suppress the flow separation phenomenon.

[0012] The perforation rate of the perforated plate should be as large as possible to reduce the influence on the noise reduction of the muffler, especially when the air flow rate in the main pipeline is low. With the increase of the gas flow rate in the main pipeline, the perforation rate of the perforated plate in the composite sound absorption structure can be appropriately reduced to protect the wire mesh.

[0013] Preferably, the interface between the side branch pipe muffler and the main pipeline is provided with a sealing ring to avoid leakage of gas and noise in the system.

[0014] The application adopts the above-mentioned side branch pipe-perforated screen composite sound absorption structure for flow pipe noise reduction, which has the following beneficial effects:

[0015] (1) The composite sound absorption structure in the application reduces the flow separation phenomenon caused by the side opening of the conventional side branch pipe muffler, makes the flow field in the main pipe more stable, and is especially suitable for scenes such as aircraft engines and wind tunnels that have high requirements for flow field quality.

[0016] (2) The composite sound absorption structure in the application has little effect on sound waves and can maximize the original noise reduction performance of the muffler. Experimental data show that the noise reduction peak after adding the perforated screen in the application only decreases slightly, and the noise reduction frequency is almost not shifted, which is significantly better than the scheme of the traditional small perforation rate perforated plate.

[0017] (3) The composite sound absorption structure in the application is simple in design, can not consider the influence of the metal mesh, and only needs to assemble the metal mesh after the original muffler design is completed. The perforated screen in the application can adapt to various side branch pipe configurations, such as side branch resonators, Herschel-Quincke (HQ) pipes, etc., without the need for complex modification of the original muffler, thereby reducing the application threshold.

[0018] (4) When the area of the side branch pipe is too large, the perforated plate with a large perforation rate or the reinforcing rib can be used to reinforce the metal mesh in the application to avoid damage to the metal mesh structure, thereby improving the service life of the composite sound absorption structure.

[0019] The technical solutions of the application will be further described in detail below through the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the side branch pipe-perforated screen composite sound absorption structure for flow pipe noise reduction of the application;

[0021] Figure 2 It is an embodiment of the side branch pipe-perforated screen composite sound absorption structure for flow pipe noise reduction of the application Figure 1 The enlarged view of A;

[0022] Figure 3 It is a front view of the HQ pipe in an embodiment of the side branch pipe-perforated screen composite sound absorption structure for flow pipe noise reduction of the application;

[0023] Figure 4 It is a structure schematic diagram of the metal mesh in an embodiment of the side branch pipe-perforated screen composite sound absorption structure for flow pipe noise reduction of the application;

[0024] Figure 5 It is a structure schematic diagram of the perforated plate in an embodiment of the side branch pipe-perforated screen composite sound absorption structure for flow pipe noise reduction of the application;

[0025] Figure 6This is a schematic diagram of the perforated screen in an embodiment of the side branch pipe-perforated screen composite sound absorption structure for flow pipe noise reduction according to the present invention;

[0026] Figure 7 This is a comparison diagram of the transmission loss of the sound absorption structures in the following embodiments of the side branch pipe-perforated screen composite sound absorption structure for flow tube noise reduction of the present invention, as well as Comparative Example 1 and Comparative Example 2.

[0027] Figure Labels

[0028] 1. HQ pipe silencer; 2. Main pipe; 3. Metal wire mesh; 4. Perforated plate; 5. Fixing bolts. Detailed Implementation

[0029] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0031] Example

[0032] A side-branch pipe-perforated screen composite sound-absorbing structure for noise reduction in flow pipes includes a main pipe 2, an HQ pipe silencer 1, and a perforated screen. The perforated screen is composed of a metal wire mesh 3 and a perforated plate 4. The HQ pipe silencer 1 is connected and fixed to the main pipe 2 by fixing bolts 5.

[0033] The HQ pipe silencer 1 was fabricated using 3D-printed resin material. Its internal hollow section is a 40mm × 10mm rectangle. Figures 1-4 As shown, the HQ pipe silencer 1 is connected to both ends of a hollow main pipe 2 with a cross-section of 51mm × 51mm. In this embodiment, the metal wire mesh 3 is a commercially available 100-mesh nickel wire mesh with a wire diameter of approximately 0.1mm. Two pieces of suitable size are cut out and pasted onto the inlet and outlet of the HQ pipe silencer 1, respectively.

[0034] like Figures 5-6 As shown, the perforated plate 4 provides support and protection for the metal mesh 3. In this embodiment, the perforation rate of the perforated plate 4 at the contact points with the inlet and outlet of the HQ pipe silencer 1 is 95%. The perforated plate 4 is located between the inlet and outlet of the HQ pipe silencer 1 and the metal mesh 3, and the three can be fixed together by welding or gluing. The connection method between the perforated plate 4, the HQ pipe silencer 1, and the metal mesh 3 in this embodiment should be determined according to the actual usage environment and equipment geometry. It is only necessary to ensure that the perforated plate 4 and the metal mesh 3 corresponding to the inlet and outlet of the HQ pipe silencer 1 are not interfered with by the connection method.

[0035] Comparative Example 1

[0036] A sound absorption structure comprises a main pipe 2, an HQ pipe muffler 1 and a metal wire mesh 3. The HQ pipe is connected to the main pipe 2 by a fixing bolt 5.

[0037] The HQ pipe muffler 1 is made of a resin material by 3D printing, and the hollow part in the cross section is a rectangle with a size of 40mm*10mm. The HQ pipe muffler 1 is connected to the hollow main pipe 2 with a cross section of 51mm*51mm at both ends. In the comparative example, the metal wire mesh 3 is a common 100-mesh nickel wire mesh with a wire diameter of about 0.1mm. Two pieces of the mesh are cut and pasted at the inlet and outlet of the HQ pipe muffler 1.

[0038] The connection mode between the HQ pipe and the metal wire mesh 3 in the comparative example should be determined according to the actual use environment and the geometry of the device, as long as the metal wire mesh 3 corresponding to the inlet and outlet of the HQ pipe muffler 1 is not interfered by the connection mode.

[0039] Comparative Example Two

[0040] A sound absorption structure comprises a main pipe 2 and an HQ pipe muffler 1. The HQ pipe muffler 1 is connected to the main pipe 2 by a fixing bolt 5.

[0041] The HQ pipe muffler 1 is made of a resin material by 3D printing, and the hollow part in the cross section is a rectangle with a size of 40mm*10mm. The HQ pipe muffler 1 is connected to the hollow main pipe 2 with a cross section of 51mm*51mm at both ends.

[0042] The sound absorption structures in the example, comparative example one and comparative example two are tested for performance.

[0043] As shown in Figure 7 the noise reduction peak of the HQ pipe muffler 1 in comparative example one is slightly reduced after adding the metal wire mesh 3, but the noise reduction frequency almost does not move, which means that when reducing the sound wave of a specific frequency, only the original muffler structure parameters need to be designed, and the influence of the metal wire mesh 3 does not need to be considered, greatly simplifying the design process.

[0044] In the example, the perforated plate 4 is added to the HQ pipe muffler 1 and the metal wire mesh 3 structure, which does not have a great influence on the sound absorption performance, thereby expanding the use environment of the sound absorption structure in the example.

[0045] Therefore, the present application adopts the above-mentioned side branch pipe-perforated screen composite sound absorption structure for flow pipe noise reduction. The structure can not only suppress the flow separation phenomenon at the inlet and outlet of the side branch pipe and improve the flow field quality of the main pipe, but also will not have a great influence on the noise reduction effect of the side branch pipe in the flow pipe. In addition, the structure is simple, does not need special design of the perforated screen, and is not limited by the shape of the main pipe and the side branch pipe, and has good application value in the field of flow pipe noise reduction.

[0046] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced equivalently, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A compound side-branch perforated panel absorber structure for flow duct noise reduction, characterized by: The muffler comprises a main pipe, a side branch pipe muffler and a perforated screen, the side branch pipe muffler is arranged on the side wall of the main pipe, and the side branch pipe muffler and the main pipe are fixed by fixing bolts; the perforated screen is arranged at the joint of the side branch pipe muffler and the main pipe.

2. A compound side-branch perforated panel absorber structure for flow duct noise reduction according to claim 1, characterized in that: The side branch pipe muffler comprises a side branch resonator, a Helmholtz resonator and an interference muffler; the side branch pipe muffler comprises a conventional structure, a segmented coiled structure and a frequency modulation structure.

3. A compound side-branch perforated panel absorber for flow duct noise reduction according to claim 1, characterized in that: The perforated screen is tightly attached to the main pipe and the side branch pipe muffler by welding, sticking or screwing.

4. A compound side-branch perforated panel absorber for flow tube noise reduction according to claim 1, characterized in that: The perforated screen is composed of a wire mesh and a perforated plate; the perforated plate is arranged between the side branch pipe muffler and the wire mesh, the wire mesh is flush with the inner wall of the main pipe; the side branch pipe muffler and the perforated plate, and the perforated plate and the wire mesh are tightly attached by welding, sticking or screwing.

5. A compound side-branch perforated panel absorber structure for flow duct noise reduction according to claim 4, characterized in that: The wire mesh is made of stainless steel, iron, titanium, nickel or copper.

6. A compound side-branch perforated panel absorber structure for flow duct noise reduction according to claim 1, characterized by: The joint of the side branch pipe muffler and the main pipe is provided with a sealing ring.

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