Sound absorption structure, acoustic liner and power propulsion system

Abstract

The utility model relates to a sound absorption structure, a sound liner and a power propulsion system. The sound absorption structure comprises one or more metamaterial sound absorption units, and each metamaterial sound absorption unit comprises a perforated plate, a sound absorption layer and a sound absorption layer, a side wall; a back plate; the perforated plate, the side wall and the back plate jointly define a sound absorption cavity; the first end and the second end, in the width direction, of the rib plate are connected with the first side wall face and the second side wall face of the side wall respectively, the first side wall face and the second side wall face are oppositely arranged, the first end, in the length direction, of the rib plate is connected with the perforated plate, and the other side of the rib plate is suspended and does not make contact with the back plate; wherein the perforated plate is bounded by a first boundary line, one side of the first boundary line is a perforated area, the other side of the first boundary line is a non-perforated area, and the position of the first boundary line corresponds to the connecting position of the rib plate and the perforated plate.

Description

Technical Field

[0001] This application relates to an acoustic absorption structure, a sound lining, and a power propulsion system. Background Art

[0002] In a power propulsion system, such as a turbofan engine which is commonly used in a gas turbine engine and is a civil aviation engine, as Figure 1 shown, the inlet air flow direction is O1. The outside atmosphere first passes through the intake nacelle A equipped with the acoustic lining device A1, then flows through the large-sized fan 1000, and then is divided into two parts of air flow, a and b. The air flow of part a is discharged from the outlet of the fan 1000; the air flow of part b is the mainstream air flow, which successively passes through the booster stage 2000 and the high-pressure compressor 3000 for boosting. After combustion in the combustion chamber 4000, it becomes high-temperature and high-pressure gas, and then expands and does work in the high-pressure turbine 5000 and the low-pressure turbine 6000, and is discharged from the outlet 7000. The engine rotating shaft is 1500, the high-pressure compressor and the high-pressure turbine connecting shaft is 8000, and the fan, the booster stage and the low-pressure turbine connecting shaft is 9000.

[0003] The noise problem of a gas turbine engine, such as a civil aviation engine, poses an important problem to the continuously growing air transportation industry. The noise level of a large civil aircraft is one of the important contents for airworthiness certification. The noise certification standard changes with time. The International Civil Aviation Organization (ICAO) Annex 16 has made detailed technical specifications for aircraft noise certification. This technical specification uses the "Effective Perceived Noise Level" (EPNL), considering three certification reference conditions: Sideline, Cutback, Approach. EPNL is used to quantify aircraft noise and considers the perceived annoyance degree measured based on the loudness. Approach: The state when the aircraft is preparing to land on the runway, and the airworthiness standards of different aircraft are different. The meanings of each condition are as follows: Cutback: The state when the aircraft takes off and taxis for a certain distance, and the airworthiness standards of different aircraft are different; Sideline: The state when the noise level is the largest after the aircraft takes off, and the airworthiness standards of different aircraft are different; Sound Power Level refers to the logarithm to the base 10 of the ratio of the sound power to the reference sound power multiplied by 10, and the unit is decibel. Blade Passing Frequency (BPF): The noise frequency caused when the blade passes through the tongue of the volute, also known as the fundamental frequency. As Figure 2 shown, a fan is a typical fluid machine. The air flow flows between the rotating rotor and the stator blade rows, generating strong tonal noise and broadband noise. The fan blades of an aeroengine widely adopt a design with fewer blade numbers and wider chord lengths. The working points that are most concerned about the external field noise are approach landing and takeoff. At the subsonic tip speed of the tip Mach number, the characteristics of the fan noise spectrum are that the blade passing frequency tone and its harmonics are superimposed on the broadband noise spectrum.

[0004] Acoustic liners are common means for controlling the noise of turbomachines. The most typical structure of an acoustic liner is the honeycomb acoustic liner structure, which consists of a perforated plate, a core layer, and a rigid backplate, forming the structure of an acoustic liner with a Helmholtz resonance cavity type. This structural form has advantages such as simple process, small structural thickness, and convenient structural layout, and is widely used.

[0005] The development of metamaterials makes it possible to achieve perfect absorption in the low-frequency and wide-frequency ranges. By designing complex and delicate acoustic absorption units and then arranging them periodically or aperiodically, an acoustic absorption structure that couples different units is finally formed to achieve perfect absorption in the low-frequency and wide-frequency bands. However, the internal structure of existing metamaterial acoustic absorption structures is complex, which brings many difficulties to processing and manufacturing and is not conducive to the development of productization.

[0006] Therefore, there is a need in the art for a new acoustic absorption structure to solve at least one of the above technical problems. Summary of the Invention

[0007] One object of the present application is to provide an acoustic absorption structure.

[0008] One object of the present application is to provide an acoustic liner part.

[0009] Another object of the present application is to provide a power propulsion system.

[0010] An acoustic absorption structure according to one aspect of the present application includes one or more metamaterial acoustic absorption units, and each metamaterial acoustic absorption unit includes: a perforated plate; side walls; a backplate; the perforated plate, the side walls, and the backplate jointly define an acoustic absorption chamber; a rib plate, the rib plate is connected to the first side wall surface and the second side wall surface of the side walls at the first end and the second end in the width direction respectively, the first side wall surface and the second side wall surface are oppositely arranged, the rib plate is connected to the perforated plate at the first end in the length direction, and the other side is suspended and not in contact with the backplate; wherein, the perforated plate is bounded by a first demarcation line, one side of the first demarcation line is a perforated area, and the other side is a non-perforated area, and the position of the first demarcation line corresponds to the connection position of the rib plate and the perforated plate.

[0011] In one or more embodiments of the acoustic absorption structure, the relationship between the length L1 of the rib plate and the length L2 of the side wall is that L1 does not exceed 0.9L2.

[0012] In one or more embodiments of the acoustic absorption structure, the rib plate is a flat plate structure and is perpendicularly connected to the first side wall surface, the second side wall surface, and the perforated plate.

[0013] In one or more embodiments of the acoustic absorption structure, the rib plate has through holes penetrating in its thickness direction.

[0014] In one or more embodiments of the sound absorption structure, the shapes of the perforations in the perforated area of the perforated plate include square, rhombus, parallelogram, trapezoid, circle, triangle, polygon with more than five sides, and star shape.

[0015] In one or more embodiments of the sound absorption structure, it includes a plurality of metamaterial sound absorption units. Among adjacent metamaterial sound absorption units, the perforated plate of one of the metamaterial sound absorption units is connected to the back plate of the other metamaterial sound absorption unit, and / or, among adjacent metamaterial sound absorption units, the side wall of one of the metamaterial sound absorption units is connected to the side wall of the other metamaterial sound absorption unit.

[0016] In one or more embodiments of the sound absorption structure, it includes a plurality of metamaterial sound absorption units, where different metamaterial sound absorption units have different rib plates, and the number and shape of the through holes of different rib plates are different, and / or different perforated plates, and the number and shape of the perforations of different perforated plates are different.

[0017] A sound lining according to another aspect of the present application includes the sound absorption structure described in any one of the above.

[0018] A power propulsion system according to another aspect of the present application includes the sound lining described above.

[0019] In one or more embodiments of the power propulsion system, the power propulsion system is a gas turbine engine, and the sound lining is disposed in the nacelle of the gas turbine engine.

[0020] The beneficial effects of the sound absorption structure, sound lining, and power propulsion system introduced in the above embodiments include, but are not limited to, based on the traditional Helmholtz resonance cavity type sound absorption structure, a rib plate fixed to the inner wall is connected to the perforated plate. Through holes are arranged on the perforated plate on one side of the rib plate, while the other side is not perforated. This rib plate increases the cavity depth, improves the low-frequency sound absorption performance of the sound absorption structure, and at the same time changes the resistance and reactance of the original Helmholtz resonance cavity. In addition, this structure provides rich degrees of freedom for designing the sound absorption unit. By connecting different sound absorption units in series or parallel, a sound absorption structure customized by the designer can be formed to achieve an ultra-wideband sound absorption effect. Additionally, by coupling each sound absorption unit and designing parameters such as the thickness, cavity depth, hole diameter, hole pitch, thickness, and length of the rib plate of each sound absorption unit, the impedance characteristics of the sound absorption structure can be customized to enable the sound absorption structure to achieve low-frequency and broadband sound absorption effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other features, properties, and advantages of the present application will become more apparent from the following description in conjunction with the drawings and embodiments, where:

[0022] Figure 1It is a schematic structural diagram of a gas turbine engine.

[0023] Figure 2 It is a schematic structural diagram of a single acoustic absorption unit of an acoustic absorption structure of an embodiment.

[0024] Figure 3 、 Figure 4 、 Figure 5 It is a schematic structural diagram of the arrangement of multiple acoustic absorption units of an acoustic absorption structure of some embodiments. Detailed implementation manners

[0025] The following further describes the present application with reference to specific embodiments and the accompanying drawings. More details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can obviously be 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 application. Therefore, the protection scope of the present application should not be limited by the content of this specific embodiment.

[0026] Meanwhile, 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 "an embodiment" or "one 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.

[0027] It can be understood that flowcharts are used in the present application to illustrate the operations performed by the systems according to the embodiments of the present application. It should be understood that, according to the actual situation, the operations before or below do not necessarily need to be precisely executed in sequence. Other operations can also be added to these processes, or one or several steps of operations can be removed from these processes.

[0028] The acoustic liner described in the following embodiments is applied to a gas turbine engine. Specifically, taking the nacelle of a turbofan engine as an example, but not limited thereto, it can be applied to any power propulsion system. Power propulsion systems with fans, blades, propfans, etc. can also be applicable, and it is not limited to gas turbine engines. For example, it can be a hybrid propulsion system including a gas turbine engine, or a pure electric drive power propulsion system with a fan, blade, or propfan to reduce fan noise and / or intake noise.

[0029] As Figures 2 to 5 shown, the acoustic absorption structure 100 includes one or more metamaterial acoustic absorption units 10, and each metamaterial acoustic absorption unit 10 includes: a perforated plate 1, a side wall 2, a back plate 3, and a rib plate 4.

[0030] The meaning of "metamaterial" here is similar to its common meaning, that is, different chemical materials or physical structures at the sub-wavelength scale are arranged periodically or aperiodically to obtain physical properties different from those of general materials.

[0031] Continue to refer to Figure 2 As shown, the perforated plate 1, the side wall 2, and the back plate 3 jointly define the sound absorption chamber 20; the rib plate 4, the first end 401 and the second end 402 of the rib plate 4 in the width direction are respectively connected to the first side wall surface 21 and the second side wall surface 22 of the side wall, the first side wall surface 21 and the second side wall surface 22 are oppositely arranged, the first end 411 of the rib plate 4 in the length direction is connected to the perforated plate 1, and the other side is suspended and not in contact with the back plate 3; wherein, the perforated plate 1 is bounded by the first demarcation line 11, on one side of the first demarcation line 11 is the perforated area 12, and on the other side is the non-perforated area 13, and the position of the first demarcation line 11 corresponds to the connection position of the rib plate 4 and the perforated plate 1. The geometric shape of the side wall 2 is provided, for example, it can be a cuboid (quadrangular prism) shown in the figure, but it is not limited thereto, for example, it can also be a honeycomb hexagonal prism structure, etc. The shapes of the perforations in the perforated area 12 of the perforated plate 1 include square, rhombus, parallelogram, trapezoid, circle, triangle, polygon with more than five sides, star, etc., and can also be a combination of perforations of different shapes.

[0032] The impedance characteristics of the sound absorption structure can be adjusted by adjusting the aperture, hole pitch, thickness of the perforated plate 1, depth of the sound absorption chamber 20, thickness t, length, distance W1 from the side wall of the rib plate 4, and the ratio of W1 to the width W2 of the side wall, etc., to obtain the required characteristic curve and achieve low-frequency and ultra-wideband sound absorption. Preferably, in some embodiments, the relationship between the length L1 of the rib plate 4 and the length L2 of the side wall 2 is that L1 does not exceed 0.9L2, so that the sound absorption effect can be further improved.

[0033] In some embodiments, the rib plate 4 is a flat plate structure, vertically connected to the first side wall surface 21, the second side wall surface 22, and the perforated plate 1. The structure of the rib plate 4 arranged vertically can further optimize the sound absorption effect.

[0034] As Figures 3 to 5 shown, in some embodiments, some rib plates 4 of the sound absorption unit 10 have through holes 41 penetrating in the thickness direction, while some rib plates 4 of the sound absorption unit 10 do not have through holes, so as to adjust the sound absorption frequency of the sound absorption unit.

[0035] Continue to refer to Figures 3 to 5 shown, in some embodiments, as Figure 3As shown, for a structure including multiple metamaterial acoustic absorption units 10, among adjacent metamaterial acoustic absorption units 10, the perforated plate 1 of one of the metamaterial acoustic absorption units 10 is connected to the back plate 3 of another metamaterial acoustic absorption unit 10. Such a connected structure is called series coupling.

[0036] In some embodiments, as Figure 4 shown, for a structure including multiple metamaterial acoustic absorption units 10, where different metamaterial acoustic absorption units have different rib plates 4, and the rib plates 4 have different numbers and shapes of through holes 41, and / or different perforated plates 1, and the perforated plates 1 have different numbers and shapes of perforations. Such a connected structure is called parallel coupling.

[0037] In some embodiments, as Figure 5 shown, it can also be a series - parallel coupling structure that is both series - coupled and parallel - coupled, that is, among adjacent metamaterial acoustic absorption units 10, there is Figure 3 the series coupling as Figure 4 shown, and there is also

[0038] Figures 3 to 5 shown, in some embodiments, for a structure including multiple metamaterial acoustic absorption units 10, where different metamaterial acoustic absorption units have different rib plates 4, and the rib plates 4 have different numbers and shapes of through holes 41, and / or different perforated plates 1, and the perforated plates 1 have different numbers and shapes of perforations.

[0039] In summary, the beneficial effects of the acoustic absorption structure, acoustic liner, and power propulsion system introduced in the above embodiments include, but are not limited to, based on the traditional Helmholtz resonance cavity - type acoustic absorption structure, connecting a rib plate fixed to the inner wall on the perforated plate. There are through holes arranged on the perforated plate on one side of the rib plate, while there are no holes on the other side. This rib plate increases the cavity depth, improves the low - frequency acoustic absorption performance of the acoustic absorption structure, and at the same time changes the resistance and reactance of the original Helmholtz resonance cavity. In addition, this structure provides rich degrees of freedom for designing the acoustic absorption unit. By connecting different acoustic absorption units in series and parallel, an acoustic absorption structure customized by the designer can be formed to achieve an ultra - wideband acoustic absorption effect. Additionally, by coupling each acoustic absorption unit and designing parameters such as the thickness, cavity depth, aperture, hole pitch of the perforated plate, and the thickness and length of the rib plate of each acoustic absorption unit, the impedance characteristics of the acoustic absorption structure can be customized, enabling the acoustic absorption structure to achieve low - frequency and broadband acoustic absorption effects.

[0040] Although this application is disclosed above with preferred embodiments, it is not used to limit this application. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of this application. Therefore, any modification, equivalent change, and decoration made to the above embodiments based on the technical essence of this application without departing from the technical solution of this application shall fall within the protection scope defined by the claims of this application.

Claims

1. A sound absorbing structure (100), characterized in that: The invention comprises one or more metamaterial sound absorbing units (10), each of which comprises: Perforated plate (1); Side wall (2); Back plate (3); The perforated plate (1), the side wall (2), and the back plate (3) together define a sound absorption chamber (20); A rib plate (4), wherein a first end (401) and a second end (402) of the rib plate (4) in the width direction are respectively connected to a first side wall surface (21) and a second side wall surface (22) of the side wall, the first side wall surface (21) and the second side wall surface (22) are arranged opposite to each other, and a first end (411) of the rib plate (4) in the length direction is connected to the perforated plate (1), and the other side is suspended in the air and is not in contact with the back plate (3); The perforated plate (1) is bounded by a first dividing line (11), one side of the first dividing line (11) is a perforated area (12), and the other side is a non-perforated area (13), and the position of the first dividing line (11) corresponds to the connection position between the rib plate (4) and the perforated plate (1).

2. The sound absorbing structure (100) according to claim 1, characterized in that: The relationship between the length L1 of the rib plate (4) and the length L2 of the side wall (2) is that L1 does not exceed 0.9L2.

3. The sound absorbing structure (100) according to claim 1, characterized in that: The rib plate (4) is a flat plate structure and is vertically connected to the first side wall surface (21), the second side wall surface (22), and the perforated plate (1).

4. The sound absorbing structure (100) according to claim 1, characterized in that: The rib plate (4) has a through hole (41) penetrating the rib plate in its thickness direction.

5. The sound absorbing structure (100) according to claim 1, characterized in that: The shapes of the holes in the perforated area (12) of the perforated plate (1) include square, rhombus, parallelogram, trapezoid, circle, triangle, polygon with more than pentagon shape, and star shape.

6. The sound absorbing structure (100) according to claim 1, characterized in that: The invention comprises a plurality of metamaterial sound absorbing units (10), wherein the perforated plate (1) of one of the adjacent metamaterial sound absorbing units (10) is connected to the back plate (3) of another metamaterial sound absorbing unit (10), and / or the side wall (2) of one of the adjacent metamaterial sound absorbing units (10) is connected to the side wall (2) of another metamaterial sound absorbing unit (10).

7. The sound absorbing structure (100) according to claim 1, characterized in that: It comprises a plurality of metamaterial sound absorbing units (10), wherein different metamaterial sound absorbing units have different ribs (4), different ribs (4) have different numbers and shapes of through holes (41), and / or different perforated plates (1), different perforated plates (1) have different numbers and shapes of perforations.

8. An acoustic lining, characterized in that: The invention comprises the sound absorbing structure (100) as claimed in any one of claims 1 to 7.

9. A power propulsion system, characterized in that: Comprising the acoustic lining member as claimed in claim 8.

10. The propulsion system according to claim 9, characterized in that: The power propulsion system is a gas turbine engine, and the acoustic lining is arranged in the nacelle of the gas turbine engine.

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