Acoustic liner and aero-engine

Abstract

The acoustic liner comprises a perforated plate, a bottom plate and a honeycomb cavity located between the perforated plate and the bottom plate and further comprises a resonance structure located in the honeycomb cavity, the resonance structure comprises a mounting plate, an elastic support and a rigid plate, the mounting plate is arranged on the inner wall face of the honeycomb cavity and extends into the cavity, one side of the elastic support is arranged at the radial inner end of the mounting plate, and the other side of the elastic support is arranged on the rigid plate. And the other side of the elastic support is connected with the rigid plate, so that the rigid plate vibrates by means of the elastic support. The acoustic liner has a good sound absorption effect. The invention further provides an aero-engine.

Description

Technical Field

[0001] The present invention relates to the field of noise reduction, and more particularly to the field of acoustic liners. Background Art

[0002] When mechanical systems, including aeroengines, operate, they generate significant noise. To reduce the impact of the noise on the environment, acoustic liners need to be arranged at key structural positions to absorb the noise and improve environmental quietness.

[0003] Traditional acoustic liners include a perforated plate, a honeycomb cavity, and a back plate, which are essentially a periodic arrangement of a large number of Helmholtz resonators. After the sound wave enters the honeycomb cavity through the perforated plate, Helmholtz resonance occurs inside the acoustic liner, dissipating the energy of the noise, thereby achieving the sound absorption effect.

[0004] When conducting the design of traditional acoustic liners, the target absorption frequencies often focus on the medium and high frequency bands while ignoring low-frequency noise, and low-frequency noise has a great destructive effect on the environment and the human body. With the increasing attention paid to low-frequency noise sources, developing acoustic liners with low-frequency sound absorption is an urgent need to address noise pollution. The sound absorption frequency of traditional acoustic liners depends on the cavity depth of the honeycomb cavity of the acoustic liner. The greater the cavity depth, the lower the absorption frequency. Therefore, to achieve lower-frequency sound absorption, the honeycomb cavity needs to have a greater depth to reduce the absorption frequency. However, due to structural space limitations, the thickness of traditional acoustic liners will be restricted. In the case where it is difficult to increase the cavity depth of the honeycomb cavity, the sound absorption frequency of traditional acoustic liners cannot be further reduced. Summary of the Invention

[0005] An object of the present invention is to provide an acoustic liner with a better sound absorption effect.

[0006] The acoustic liner for achieving the above object includes a perforated plate, a bottom plate, and a honeycomb cavity located between the perforated plate and the bottom plate, and further includes a resonance structure located in the honeycomb cavity. The structure includes a mounting plate, an elastic support, and a rigid plate. The mounting plate is arranged to extend from the inner wall surface of the honeycomb cavity into the cavity. One side of the elastic support is arranged at the radial inner end of the mounting plate, and the other side is connected to the rigid plate, so that the rigid plate vibrates by means of the elastic support.

[0007] In one or more embodiments, the acoustic liner further includes a plurality of resonance structures, and adjacent resonance structures share the same mounting plate or the same rigid plate.

[0008] In one or more embodiments, the elastic support is an annular member.

[0009] In one or more embodiments, a plurality of elastic supports are circumferentially arranged on the mounting plate.

[0010] In one or more embodiments, the resilient support is rubber, a spring, or wire mesh.

[0011] In one or more embodiments, the rigidity of the rigid plate is greater than that of the resilient support.

[0012] In one or more embodiments, the acoustic lining is a single-degree-of-freedom acoustic lining, a two-degree-of-freedom acoustic lining, or a multi-degree-of-freedom acoustic lining.

[0013] In one or more embodiments, the resilient support is disposed at a radial distance of 10% to 80% from the inner wall of the honeycomb cavity to the center of the honeycomb cavity along the connecting line.

[0014] In one or more embodiments, the rigid plate is a series of plate members of different weights, and each of the plate members is alternatively disposed on the resilient support.

[0015] In one or more embodiments, the mounting plate is integrally formed with the honeycomb cavity, and the resilient support is adhesively bonded to the rigid plate and the mounting plate.

[0016] The present invention also provides an aeroengine including the above-mentioned acoustic lining.

[0017] By constructing a resonance structure including a mounting plate, a resilient support, and a rigid plate, the above-mentioned acoustic lining further introduces the local resonance principle for sound absorption on the basis of the traditional sound absorption method using the Helmholtz resonance principle. Under the action of noise, the rigid plate and the resilient support inside the honeycomb cavity can generate local resonance, having a significant sound absorption effect on low-frequency noise pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other features, properties, and advantages of the present invention will become more apparent from the following description in conjunction with the drawings and embodiments, where:

[0019] Figure 1 is a schematic structural diagram of the acoustic lining;

[0020] Figures 2A - 2B is a schematic diagram of an embodiment of a single resonance structure located in a single honeycomb cavity;

[0021] Figures 3A - 3B is a schematic diagram of an embodiment of two resonance structures located in a single honeycomb cavity;

[0022] Figure 4 is a top view of a single honeycomb cavity;

[0023] Figure 5 is a sectional view of the annular resilient support.

[0024] DESCRIPTION OF SYMBOLIC MARKINGS

[0025] 1 perforated plate

[0026] 2 honeycomb cavity

[0027] 3 back plate

[0028] 10 resonance structure

[0029] 11 mounting plate

[0030] 12 elastic support

[0031] 13 rigid plate Detailed implementation manners

[0032] The present invention will be further described below in conjunction with specific embodiments and the accompanying drawings. More details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention is clearly capable of being implemented in many other ways different from this description. Those skilled in the art can make similar generalizations and deductions according to the actual application situation without departing from the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0033] It should be noted that these and subsequent other drawings are only examples, and they are not drawn under the condition of equal proportions, and should not be used to limit the actual claimed protection scope of the present invention.

[0034] Figure 1 A conventional acoustic lining structure is shown, including a perforated plate 1, a honeycomb cavity 2 and a back plate 3. The honeycomb cavity 2 serves as a Helmholtz resonator and uses the principle of acoustic cavity resonance for sound absorption. The cavity depth of the honeycomb cavity affects the sound absorption frequency. The deeper the cavity depth H, the lower the sound absorption frequency. However, the installation area of the acoustic lining is often subject to strict size limitations. Therefore, it is difficult to achieve low-frequency sound absorption by increasing the cavity depth.

[0035] In view of this, the acoustic lining structure described in the present disclosure can obtain better low-frequency sound absorption effect without increasing the cavity depth.

[0036] As Figure 2A and 2B shown, the acoustic lining further includes a resonance structure 10 disposed in the honeycomb cavity 2. The resonance structure 10 includes a mounting plate 11, an elastic support 12 and a rigid plate 13.

[0037] The mounting plate 11 is arranged to extend from the inner wall surface of the honeycomb cavity 2 towards the cavity, and is produced by an integral forming method such as 3D printing. One side of the elastic support 12 is disposed at the radially inner end of the mounting plate 11, and the other side is connected to the rigid plate 13. The rigid plate 13 with the elastic support 12 can, by means of the action of the elastic support 12, generate local resonance with the incident noise, and use resonance to absorb the noise energy, so as to achieve the purpose of further sound absorption.

[0038] In Figures 2A - 2B the illustrated embodiment, one side of the upper and lower sides of the elastic support 12 is fixedly connected to the mounting plate 11, and the other side is fixedly connected to the rigid plate 13, such as by gluing.

[0039] Preferably, the rigid plate 13 is alternatively arranged on the elastic support. The rigid plate 13 is a series of plate members with different weights. By changing the weight of the rigid plate 13, the vibration effect can be significantly affected, and thus the sound absorption effect can be affected.

[0040] The resonance structure 10 divides the honeycomb cavity 2 into upper and lower chambers. The two ends of the rigid plate 13 do not abut against the inner wall of the honeycomb cavity 2 to allow the rigid plate 13 to vibrate itself.

[0041] In some other embodiments, one side of the left and right sides of the elastic support 12 is fixedly connected to the mounting plate 11, and the other side is fixedly connected to the rigid plate 13. At this time, the rigid plate is provided with a raised annular member to be fixed to the elastic support 12, but the rigid plate still needs to be kept parallel.

[0042] The elastic support 12 includes, but is not limited to, materials such as rubber, spring, or wire mesh. The support stiffness can be adjusted by changing the stiffness and thickness of the elastic support. Therefore, according to the sound absorption intensity, the materials, stiffness, and thickness of the elastic supports 12 in different honeycomb cavities can be different.

[0043] The elastic support 12 can be an integral annular member, as Figure 5 shown; it can also be arranged as a plurality of block members circumferentially distributed on the rigid plate 13. The rigid plate 13 can be a ring or a plurality of raised members circumferentially distributed on the inner wall of the honeycomb cavity 2.

[0044] The rigid plate 13 is made of a material with a greater stiffness than the elastic support 12 and has a certain mass. By changing the thickness of the rigid plate 13 or changing its material, the mass of the rigid plate can be adjusted.

[0045] In some embodiments, the elastic support is arranged at a radial distance of 10% - 80% from the connection line starting from the inner wall of the honeycomb cavity to the center of the honeycomb cavity, as Figure 4 shown by h in. The principle for setting the position of the elastic support 12 is that it needs to have a certain gap from the inner wall of the honeycomb cavity 2.

[0046] As described above, the rigid plate 13 and the elastic support 12 form a local resonance system. The rigid plate 13 with the elastic support 12 is added in the honeycomb cavity body, and its vibration frequency is the sound absorption frequency of this local resonance structure. The vibration frequency or the sound absorption frequency increases with the increase of the stiffness of the elastic support and decreases with the increase of the mass of the rigid plate. Based on this principle, the sound absorption frequency of the local resonance system can be adjusted.

[0047] Based on the Helmholtz resonance absorption of traditional acoustic liners, the local resonance principle is further introduced. The inner mounting plate 11 and the elastic support 12 in the honeycomb cavity can generate local resonance under the action of noise, thereby consuming the noise energy and achieving a better sound absorption effect.

[0048] The local resonance principle is a method of using the structural resonance in phononic crystals to consume noise energy and reduce noise. Phononic crystals are periodic composite materials with special acoustic properties. The most important property is that they have a strong inhibitory effect on the noise within the bandgap frequency range and do not affect the propagation of noise outside the bandgap. According to different implementation principles, phononic crystals can be divided into local resonance type phononic crystals and Bragg scattering phononic crystals.

[0049] The difference between the local resonance principle and the Helmholtz resonance is that the Helmholtz resonance uses the vibration of fluids such as air in the cavity to dissipate noise energy, while the local resonance uses the vibration of structures such as solids to dissipate noise energy.

[0050] Since the sound absorption frequency of local resonance depends on the parameters of the partition, there is no need to change the depth of the honeycomb cavity and increase the thickness of the acoustic liner. After adopting the present invention, the low-frequency sound absorption effect of the acoustic liner can be enhanced without increasing the thickness of the acoustic liner.

[0051] In some embodiments, as Figures 3A - 3B shown, the acoustic liner further includes a plurality of resonance structures, and adjacent resonance structures share the same mounting plate 11 or the same rigid plate 13.

[0052] The above-mentioned acoustic liner with resonance structures can be applied to single-degree-of-freedom acoustic liners, double-degree-of-freedom acoustic liners or multi-degree-of-freedom acoustic liners, all of which have the same sound absorption effect. The single-degree-of-freedom acoustic liner includes a perforated plate, a honeycomb core layer and a back plate; the double-degree-of-freedom acoustic liner includes two superimposed honeycomb cores, that is, it includes a perforated plate, a honeycomb core, an intermediate layer, a honeycomb core and a back plate; the multi-degree-of-freedom acoustic liner includes multiple honeycomb structures.

[0053] Combined with the introduction of the above acoustic liner, an engine including the above acoustic liner can also be understood to have a better sound absorption effect.

[0054] In the description of the present application, it should be understood that the orientation or positional relationship indicated by orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom", etc. is usually based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description. Without contrary explanation, these orientation words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of the present application; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0055] The present application uses specific terms to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0056] Although the present invention is disclosed above in preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. Acoustic lining, comprising a perforated plate, a bottom plate, and a honeycomb cavity located between the perforated plate and the bottom plate, Characterized in that, It further includes A resonance structure located within the honeycomb cavity, the structure comprising a mounting plate, an elastic support, and a rigid plate. The mounting plate extends from the inner wall of the honeycomb cavity towards the cavity interior. One side of the elastic support is disposed at the radially inner end of the mounting plate, and the other side is connected to the rigid plate, enabling the rigid plate to vibrate by means of the elastic support.

2. The acoustic lining according to claim 1, Characterized in that, The acoustic lining further includes a plurality of resonance structures, and adjacent resonance structures share the same mounting plate or the same rigid plate.

3. The acoustic lining according to claim 1, Characterized in that, The elastic support is an annular member.

4. The acoustic lining according to claim 1, Characterized in that, A plurality of elastic supports are circumferentially arranged on the mounting plate.

5. The acoustic lining according to claim 1, Characterized in that, The elastic support is rubber or a spring or a wire mesh.

6. The acoustic lining according to claim 1, Characterized in that, The rigidity of the rigid plate is greater than the rigidity of the elastic support.

7. The acoustic lining according to claim 1, Characterized in that, The acoustic lining is a single-degree-of-freedom acoustic lining or a double-degree-of-freedom acoustic lining or a multi-degree-of-freedom acoustic lining.

8. The acoustic lining according to claim 1, Characterized in that, The elastic support is disposed at a radial distance of 10% - 80% of the line connecting from the inner wall of the honeycomb cavity to the center of the honeycomb cavity.

9. The acoustic lining according to claim 1, Characterized in that, The rigid plate is a series of plate members with different weights, and each plate member is replaceably disposed on the elastic support.

10. The acoustic lining according to claim 1, Characterized in that, The mounting plate is integrally formed with the honeycomb cavity, and the elastic support is adhesively bonded to the rigid plate and the mounting plate.

11. An aeroengine, Characterized in that, It includes the acoustic lining according to any one of claims 1 - 10.

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