CN213566437U - Sound absorption liner for aircraft engine - Google Patents

Abstract

The utility model discloses an aeroengine sound absorption liner, its characterized in that: including engine nacelle inner wall, half-wave pipe, the half-wave pipe mouth of pipe, arrange engine nacelle inner wall in the half-wave pipe, the half-wave pipe mouth of pipe is half-wave's both ends opening, half-wave pipe both ends opening or one end are sealed with sealed shutoff end and are formed the quarter-wave pipe and have length difference, most of exist the half-wave pipe or the quarter-wave pipe of length difference closely arrange in engine nacelle inner wall, regulate and control natural frequency through geminate transistors length control, and then form the noise reduction of broadband. And furthermore, a micropunch plate with micropunch holes is additionally arranged at the pipe opening of the half-wave long pipe for plugging, and a sound absorption material is additionally arranged on the inner surface of the micropunch plate so as to further improve the sound absorption effect. The utility model discloses simple structure, weight are lighter, overcome the narrow shortcoming of single degree of freedom honeycomb micro-perforated structure sound lining sound absorption frequency band, form the sound absorption liner of the design of making an uproar falls in easy broadband.

Description

Sound absorption liner for aircraft engine

Technical Field

The utility model belongs to the technical field of noise control, especially, relate to an aeroengine noise sound absorption liner.

Background

At present, an aeroengine silencing nacelle is mainly based on a honeycomb micro-perforated plate structure, the honeycomb micro-perforated plate can be actually regarded as a helmholtz resonant cavity which is regularly arranged, the acoustic liner has a good sound absorption effect near a natural frequency, but the sound absorption effect is poor in other frequency bands, the engine works in a complex environment, the generated noise is continuously changed, and the limitation of the traditional single-degree-of-freedom honeycomb micro-perforated plate structure is exposed. In order to overcome the defect of sound absorption performance of the acoustic liner of the single-degree-of-freedom honeycomb micro-perforated structure, the multi-degree-of-freedom honeycomb micro-perforated structure is further provided, but the design of the multi-degree-of-freedom structure is complex, the structural design is realized on a relatively thin aeroengine sound-absorbing short bulkhead, meanwhile, the use requirement is also met, and certain difficulty exists in the actual application at present.

Disclosure of Invention

An object of the utility model is to provide an aeroengine sound absorption liner overcomes the narrow shortcoming of single degree of freedom honeycomb micro-perforated structure sound liner sound absorption frequency band.

An aircraft engine sound absorbing liner characterized by: including engine nacelle inner wall, half-wave pipe mouth of pipe, arrange engine nacelle inner wall in the half-wave pipe, the half-wave pipe mouth of pipe is half-wave's both ends opening, and half-wave pipe both ends opening just has length difference, and most amount of the half-wave pipe that has length difference closely arranges in engine nacelle inner wall, regulates and control natural frequency through controlling half-wave pipe length, and then forms the noise reduction of broadband.

Furthermore, a micropunch plate with micropunch holes is additionally arranged at the pipe opening of the half-wave long pipe for plugging so as to meet the possible pneumatic requirement of the engine.

Furthermore, the sound absorption material is additionally arranged on the inner surface of the micro-perforated plate so as to further improve the sound absorption effect.

Furthermore, one end of the opening at the two ends of the half-wave tube is sealed by a sealed plugging end to form a quarter-wave tube, and the length of the half-wave tube or the length of the modified quarter-wave tube is different, so that the frequency adjustability of the sound absorption pad is enhanced by arranging a plurality of quarter-wave tubes with different lengths.

Furthermore, the cross section of the half-wave long tube can be various, and can be rectangular, circular, triangular or other polygonal.

The utility model has the advantages that: the utility model discloses a built-in half-wave long pipe improves sound lining wide screen area sound absorption effect in the sound lining, and this kind of sound lining is simple structure light in weight not only, still has the sexual function of working in the abominable intake duct environment of aeroengine. The sound liner structure with the introduced half-wave long tube changes the difficulty of multi-freedom design of the traditional honeycomb micro-perforated structure, simplifies the multi-freedom design, can realize the multi-freedom of the structure change of the sound absorption frequency band by changing the length of the tube, or additionally installing a micro-perforated plate and a sound absorption material, or plugging a pipe orifice at one end to form a quarter-wave long tube, can realize the wide-screen control of the engine noise, and can flexibly design the wide frequency band.

Drawings

FIG. 1 is a general schematic view of the present invention in an aircraft engine nacelle application;

FIG. 2 is a schematic view of the sectional structure of the main body structure of the present invention;

FIG. 3 is a schematic view of the nozzle of the half-wave tube in FIG. 2 with the microperforated plate and the sound absorbing material added;

FIG. 4 is a perspective view of the half-wave tube in FIG. 2 with the tube opening sealed to form a quarter-wave tube;

in the figure: 1 engine nacelle inner wall, 2 half-wave long pipes, 3 half-wave long pipe mouths, 4 micro-perforations, 5 sound absorbing materials, 6 micro-perforated plates, 7 shutoff ends, 8 quarter-wave long pipes.

Detailed Description

The structure of the present invention will be described in detail with reference to the accompanying drawings:

an aircraft engine sound absorbing liner characterized by: including engine nacelle inner wall 1, half-wave long tube 2, half-wave long tube mouth of pipe 3, place engine nacelle inner wall 1 in half-wave long tube 2, half-wave long tube mouth of pipe 3 is half-wave's both ends opening, 2 both ends openings of half-wave long tube and there are length difference, the half-wave long tube that exists length difference of most volume closely arranges in engine nacelle inner wall 1, regulates and control natural frequency through controlling half-wave long tube 2 length, and then forms the noise reduction of broadband effect, half-wave long tube 2 the cross section can be manifold, both can be the rectangle, also can be for circular, can also be triangle-shaped or other polygons. Further, a micropunch plate 6 with micropunch holes 4 is additionally arranged at the pipe opening 3 of the half-wave long pipe for plugging so as to meet the possible pneumatic requirements of the engine; install sound absorbing material 5 additional at the internal surface of microperforated panel 6 to further improve the sound absorption effect, with the one end of half-wave pipe both ends opening part seal with sealed shutoff end 7 and form quarter-wave pipe 8, and this kind of half-wave pipe 2 or the quarter-wave pipe 8 length after changing is different, thereby strengthens the frequency controllability of this kind of sound absorption liner through arranging many numbers of length difference's quarter-wave pipe 8. When radiation noise passes through the noise elimination structure, sound waves enter the pipe from the pipe opening 3 of the half-wave long pipe at one end of the half-wave long pipe and are transmitted out from the pipe opening 3 of the half-wave long pipe at the other end through the pipe, a phase difference exists between the sound waves at the moment and the sound waves at the pipe opening 3 of the half-wave long pipe, and the sound waves are overlapped and interfered when the phase difference is 180 degrees, so that the noise reduction effect is achieved.

The length is different between half-wave long pipe 2, has certain length difference between half-wave long pipe 2, and specific pipe length can be calculated by following formula:

wherein the content of the first and second substances,

being the speed of sound in air,

for the natural frequency of the half-wave long tube 2, the design of the tube length can be as follows

Is set to the target noise frequency and,

=1,2 …. The tube length can be designed through the formula so as to achieve the purpose of wide screen band noise reduction of target frequency. According to the scheme, the length difference exists between the half-wave pipes, the length of the half-wave pipes is calculated through a natural frequency formula according to a required noise reduction frequency band, and the sound absorption liner structure meeting the target frequency band is further designed.

The specific tube length of the quarter wave tube 8 added to the plugging end 7 can be calculated by the following formula:

wherein the parameters are the same as the formula of the half-wave tube. It can be seen from this formula that the introduction of the quarter wave tube 8 makes the design of the tube length more flexible.

According to the above scheme, this kind of sound absorption pad structure is located fan turbine cavity wall, and this kind of fan turbine cavity has the difference at different model turbofan engines, so the utility model provides a this kind of aeroengine sound absorption liner can design the appearance when being applied to different model turbofan engines, and then the better turbofan engine fan turbine cavity of blending into a certain model. Utilize the utility model discloses, can realize carrying out wide screen area control to engine noise to this broadband can carry out nimble design.

The foregoing is a more detailed description of the present invention, taken in conjunction with the specific preferred embodiments thereof, and it is not intended that the invention be limited to the specific embodiments shown and described. For those skilled in the art to which the invention pertains, equivalent substitutes or obvious modifications may be made without departing from the spirit of the invention, and the same properties or uses are deemed to fall within the scope of the invention as defined by the claims appended hereto.

Claims (5)

1. An aircraft engine sound absorbing liner characterized by: the half-wave tube type engine nacelle comprises an engine nacelle inner wall (1), a half-wave tube (2) and a half-wave tube opening (3), wherein the engine nacelle inner wall (1) is arranged in the half-wave tube (2), the half-wave tube opening (3) is an opening at two ends of the half-wave tube, the length of the opening at two ends of the half-wave tube (2) is different, and the half-wave tube (2) with the length difference is closely distributed in the engine nacelle inner wall (1) in most quantities.

2. The aircraft engine sound absorbing liner according to claim 1 wherein: a microperforated plate (6) with microperforations (4) is additionally arranged at the opening (3) of the half-wave long pipe for plugging.

3. The aircraft engine sound absorbing liner according to claim 2 wherein: and a sound absorption material (5) is additionally arranged on the inner surface of the micro-perforated plate (6).

4. An aircraft engine sound absorbing liner according to claim 2 or 3, wherein: and one end of the two end openings of the half-wave long tube (2) is sealed by a sealed plugging end (7) to form a quarter-wave long tube (8).

5. An aircraft engine sound-absorbing liner according to any one of claims 1 to 3, wherein: the cross section of the half-wave long pipe (2) is rectangular.

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