A dual noise reduction line silencer for an aircraft environmental control system

Abstract

This invention discloses a dual-noise-reducing pipeline silencer for an aircraft environmental control system, comprising a shell, an inner tube, a partition, a first sound-absorbing cotton, and a noise-reducing core. The partition divides the annular space between the shell and the inner tube into multiple silencing chambers. At least one silencing chamber contains the first sound-absorbing cotton, and at least one silencing chamber does not contain sound-absorbing cotton. The inner tube has a first through-hole on the wall of the corresponding silencing chamber. The noise-reducing core is placed inside the inner tube and consists of a core shell, a second sound-absorbing cotton, and a support plate. The core shell has a second through-hole and is supported by the support plate against the inner wall of the inner tube. When noise passes through the inner tube, the sound energy enters the silencing chamber through the first through-hole and the core shell through the second through-hole, where it is consumed by the sound-absorbing cotton or attenuated by the silencing chamber, thus achieving dual noise reduction. This invention significantly enhances the noise reduction capability of the silencer without increasing its volume and is suitable for space-constrained aircraft environmental control pipelines.

Description

Technical Field

[0001] This invention belongs to the field of noise control technology for aircraft environmental control systems, specifically relating to a pipeline silencer structure that combines resistive and reactive noise reduction with built-in core noise reduction. Background Technology

[0002] The aircraft's environmental control system (ECS) is responsible for providing regulated air to the cockpit and avionics bay. The high-speed airflow within its ducts generates significant aerodynamic noise, severely impacting passenger comfort and the operating environment of onboard equipment. To suppress this noise, silencers are typically installed on the ECS ducts.

[0003] Existing silencers mostly employ a resistive silencing structure with a silencing cavity, or fill the silencing cavity with sound-absorbing cotton to form a resistive silencing structure. However, such silencers only utilize the annular space between the outer shell and the inner tube for noise reduction. Due to the limited installation space on the aircraft, the expansion ratio of the silencer and the amount of sound-absorbing cotton filling are difficult to increase significantly, thus limiting both the noise reduction volume and the effective noise reduction band.

[0004] Some improvement solutions involve perforating the inner tube wall and creating an outer cavity, which can broaden the frequency band, but the utilization rate of sound energy propagating in the central area of ​​the inner tube is still insufficient, and the overall noise reduction effect needs to be further enhanced. Summary of the Invention

[0005] The present invention aims to provide a dual noise reduction pipeline silencer for aircraft environmental control systems, which significantly enhances the noise reduction function of the pipeline silencer for aircraft environmental control systems without significantly increasing the volume of the silencer.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A dual-noise reduction pipeline silencer for an aircraft environmental control system, comprising: The outer casing is a hollow shell; The inner tube is disposed in a cavity inside the outer shell and is coaxial with the outer shell. An annular space is formed between the outer wall of the inner tube and the inner wall of the outer shell. The inner tube is a cavity shell. A partition, at least one of the partitions is fixed in the annular space between the outer shell and the inner tube, the partition dividing the annular space into multiple sound-absorbing chambers; The first through hole, and multiple first through holes are distributed on the inner tube in the area corresponding to the silencing cavity and penetrate the tube wall of the inner tube; The noise reduction core is disposed inside the cavity of the inner tube. The noise reduction core includes a core shell, a second sound-absorbing cotton and a support plate. The core shell has an internal cavity, and the second sound-absorbing cotton is filled inside the internal cavity of the core shell. Multiple second through holes are opened on the shell wall of the core shell. The support plate is connected between the outer wall of the core shell and the inner wall of the inner tube, thereby supporting and fixing the core shell inside the cavity of the inner tube.

[0007] As one approach: multiple partitions are spaced apart along the axial direction of the outer shell, so that multiple silencing chambers are arranged sequentially along the airflow direction, wherein at least one silencing chamber is filled with first sound-absorbing cotton to form a resistive silencing chamber, and at least one silencing chamber is not filled with sound-absorbing cotton to form a resistive silencing chamber.

[0008] As one embodiment: the core shell includes a cylindrical body and a bottom shell connected to one or both ends of the cylindrical body for sealing one or both ends of the cylindrical body. The space enclosed by the cylindrical body and the bottom shell is filled with second sound-absorbing cotton, and multiple second through holes are provided on the cylindrical body and / or the bottom shell.

[0009] As one possible solution: the core shell is cylindrical, and the axis of the core shell coincides with the axis of the inner tube.

[0010] As one option: a support plate is provided radially along the core shell, the support plate extending and connecting to the inner wall of the inner tube.

[0011] As one possible solution: the first through hole is a uniformly dense array of small holes.

[0012] As one possible solution: the second through hole is a uniformly dense array of small holes.

[0013] As one possible solution: the second sound-absorbing cotton is an aerospace porous sound-absorbing material.

[0014] As one possible solution: the first sound-absorbing cotton is an aerospace porous sound-absorbing material.

[0015] An aircraft environmental control system comprising any of the aforementioned dual noise reduction pipeline silencers for aircraft environmental control systems.

[0016] Compared with the prior art, the silencer of the present invention has the following characteristics: 1. A perforated core silencing structure (i.e. a noise reduction core) is added inside the inner tube, which works in conjunction with the annular silencing cavity of the outer shell to form a dual noise reduction path. This significantly improves the overall noise reduction of the muffler without increasing its volume and widens the effective noise reduction band.

[0017] 2. The silencing cavity between the outer shell and the inner tube can have both resistive and reactive silencing functions, which can be flexibly adjusted; the core shell and the second sound-absorbing cotton constitute a sound absorber, which has a good absorption effect on mid-high frequency and some low frequency noise.

[0018] 3. The overall structure is compact, and the parts are easy to manufacture and assemble, making it suitable for installation and use in space-constrained environments such as aircraft environmental control pipelines. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the axial cross-sectional structure of the external noise reduction structure in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the axial cross-sectional structure of the overall noise reduction structure in an embodiment of the present invention.

[0021] The markings in the diagram are: 1-outer shell, 2-inner tube, 3-partition, 4-first silencing cavity, 5-second silencing cavity, 6-first sound-absorbing cotton, 7-first through hole, 8-noise-reducing core, 9-core shell, 10-bottom shell, 11-second sound-absorbing cotton, 12-second through hole, 13-support plate. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should not be construed that the scope of the subject matter of the present invention is limited to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0023] like Figure 1 As shown, the dual noise reduction pipeline silencer of the aircraft environmental control system in this embodiment includes an outer shell 1, an inner tube 2, partitions 3, first sound-absorbing cotton 6, and a noise reduction core 8. The outer shell 1 is cylindrical, and the inner tube 2 is coaxially installed inside it. The two are sealed at both ends to form a closed annular space, generally using a sealing plate. Three annular partitions 3 are fixed axially between the outer shell 1 and the inner tube 2, dividing the annular space into a first silencing cavity 4, a second silencing cavity 5, a third silencing cavity, and a fourth silencing cavity. The fourth silencing cavity is filled with the first sound-absorbing cotton 6 to form a resistive silencing cavity; the first silencing cavity 4, the second silencing cavity 5, and the third silencing cavity are not filled with sound-absorbing cotton and are used as resistive silencing cavities. The inner tube 2 has a large number of uniformly distributed first through holes 7 in the tube wall area corresponding to each silencing cavity.

[0024] The noise reduction core 8 is installed at the center of the inner tube 2. The noise reduction core 8 includes a cylindrical core shell 9, a bottom shell 10, or two bottom shells 10. In this embodiment, one bottom shell 10 is used (e.g., Figure 2 As shown, Figure 2 In the case of two bottom shells 10, one end of the core shell 9 is sealed by the bottom shell 10 (when there is only one bottom shell 10, the bottom shell 10 seals the end of the core shell 9 facing the gas inflow, or in other words, the bottom shell 10 is directly facing the gas inflow direction), and the other end of the core shell 9 is open without being sealed by the bottom shell 10. The core shell 9 and the bottom shell 10 form a cylindrical cavity, which is filled with second sound-absorbing cotton 11. Numerous evenly distributed second through holes 12 are opened on the cylindrical peripheral wall of the core shell 9 and on the bottom shell 10. The support plate 13 consists of multiple radially arranged strip-shaped components ( Figure 2The inner tube 2 has three cross-sections along its axial direction. Each cross-section is perpendicular to the axis of the inner tube 2. Four support plates 13 are evenly distributed within each cross-section, with the intervals between adjacent support plates 13 forming an airflow channel. One end of each support plate 13 is fixed to the outer wall of the core shell 9, and the other end extends radially outward and is fixed to the inner wall of the inner tube 2, thus supporting the entire core shell 9 along the axis of the inner tube 2. The outer diameter of the core shell 9 is smaller than the inner diameter of the inner tube 2, ensuring that airflow can smoothly pass through the annular channel between the core shell 9 and the inner tube 2. The cross-section of the support plate 13 can be designed to be streamlined to reduce airflow resistance.

[0025] In actual operation, the airflow carrying noise flows into the inner tube 2 from one end of the silencer. As the noise waves propagate along the inner tube 2, part of the sound energy enters the fourth silencing cavity through the first through-hole 7 on the inner wall of the inner tube 2, where it is converted into heat energy and dissipated under the friction and damping effect of the first sound-absorbing cotton 6. Another part of the sound energy enters the second and third silencing cavities, where impedance mismatch caused by abrupt changes in cross-section (i.e., the first through-hole 7) leads to sound wave reflection and interference, causing attenuation. Simultaneously, the sound energy propagating along the central region of the inner tube 2 enters the core shell 9 through the second through-hole 12 on the shell wall of the noise-reducing core 8, where it is effectively absorbed by the second sound-absorbing cotton 11. Through this dual sound-absorbing structure of "outer cavity + inner core," the noise is attenuated multiple times along its propagation path, significantly enhancing the overall noise reduction capability of the silencer.

[0026] Both the first sound-absorbing cotton 6 and the second sound-absorbing cotton 11 can be made of high-temperature resistant glass fiber cotton or basalt fiber cotton to meet the temperature requirements of the bleed air of the aircraft environmental control system. In other embodiments, the number of silencing cavities and the method of filling with sound-absorbing cotton can be flexibly designed according to the required noise reduction spectral characteristics; the core shell 9 can also be a closed cylinder with both ends sealed by the bottom shell 10, and the second through hole 12 is opened on both the cylinder and the bottom shell 10.

[0027] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-noise reduction pipeline silencer for an aircraft environmental control system, characterized in that, include: The outer shell (1) is a hollow shell; Inner tube (2), the inner tube (2) is set in the cavity inside the outer shell (1) and is coaxial with the outer shell (1). The outer wall of the inner tube (2) and the inner wall of the outer shell (1) form an annular space. The inner tube (2) is a cavity shell. At least one of the partitions (3) is fixed in the annular space between the outer shell (1) and the inner tube (2), and the partition (3) divides the annular space into multiple sound-absorbing cavities; First through hole (7), multiple first through holes (7) are distributed on the inner tube (2) in the area corresponding to the sound-absorbing cavity and penetrate the tube wall of the inner tube (2); The noise reduction core (8) is disposed inside the cavity of the inner tube (2). The noise reduction core (8) includes a core shell (9), a second sound-absorbing cotton (11), and a support plate (13). The core shell (9) has an internal cavity. The second sound-absorbing cotton (11) is filled in the internal cavity of the core shell (9). Multiple second through holes (12) are opened on the shell wall of the core shell (9). The support plate (13) is connected between the outer wall of the core shell (9) and the inner wall of the inner tube (2), thereby supporting and fixing the core shell (9) inside the cavity of the inner tube (2).

2. The dual noise reduction pipeline silencer for an aircraft environmental control system according to claim 1, characterized in that: Multiple partitions (3) are spaced apart along the axial direction of the outer shell (1), so that multiple silencing chambers are arranged sequentially along the airflow direction. At least one silencing chamber is filled with first sound-absorbing cotton (6) to form a resistive silencing chamber, and at least one silencing chamber is not filled with sound-absorbing cotton to form a resistant silencing chamber.

3. The dual noise reduction pipeline silencer for an aircraft environmental control system according to claim 1, characterized in that: The core shell (9) includes a cylindrical body and a bottom shell (10) connected to one or both ends of the cylindrical body for sealing one or both ends of the cylindrical body. The space enclosed by the cylindrical body and the bottom shell (10) is filled with second sound-absorbing cotton (11), and multiple second through holes (12) are provided on the cylindrical body and / or the bottom shell (10).

4. A dual-noise reduction pipeline silencer for an aircraft environmental control system according to claim 1, characterized in that: The core shell (9) is cylindrical, and the axis of the core shell (9) coincides with the axis of the inner tube (2).

5. A dual-noise reduction pipeline silencer for an aircraft environmental control system according to claim 4, characterized in that: A support plate (13) is provided radially along the core shell (9), and the support plate (13) extends and connects to the inner wall of the inner tube (2).

6. A dual-noise reduction pipeline silencer for an aircraft environmental control system according to claim 1, characterized in that: The first through hole (7) is a uniformly dense array of small holes.

7. A dual-noise reduction pipeline silencer for an aircraft environmental control system according to claim 3, characterized in that: The second through hole (12) is a uniformly dense array of small holes.

8. A dual-noise reduction pipeline silencer for an aircraft environmental control system according to claim 1, characterized in that: The second sound-absorbing cotton (11) is an aviation porous sound-absorbing material.

9. A dual-noise reduction pipeline silencer for an aircraft environmental control system according to claim 3, characterized in that: The first sound-absorbing cotton (6) is an aviation porous sound-absorbing material.

10. An aircraft environmental control system, characterized in that: The aircraft environmental control system includes a dual noise reduction pipeline silencer as described in any one of claims 1 to 9.

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