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RU-2803661-C2 - NACELLE AIR INTAKE WITH ACOUSTIC PANEL

RU2803661C2RU 2803661 C2RU2803661 C2RU 2803661C2RU-2803661-C2

Abstract

FIELD: turbojet engines. SUBSTANCE: air intake (1) of the turbojet engine nacelle contains a ring structure (110), including an outer fairing (100) defining the outer aerodynamic surface, and an inner fairing (102) defining the inner aerodynamic surface. The outer (100) and inner (102) fairings are connected at the front downstream by the edge (108) of the air intake, forming the leading edge. The inner fairing (102) includes an outer skin (114) attached to the edge (108) of the air intake via an upstream mounting flange (118). The outer casing (114) is configured to be attached to the outer casing (116) of the fan by means of a downstream mounting flange (122). The air intake (1) contains individual acoustic panels (2) attached to the outer skin (114) and containing a perforated acoustic skin (200) and a cellular core (202). EFFECT: simplification of maintenance and repair is achieved. 13 cl, 11 dwg

Inventors

  • CARUEL PIERRE
  • DESJOYEAUX BERTRAND
  • LEROYER BERTRAND
  • VERSAEVEL MARC
  • VALLEROY LAURENT GEORGES

Dates

Publication Date
20230919
Application Date
20200420
Priority Date
20190426

Claims (15)

  1. 1. The air intake (1) of the nacelle of a turbojet engine, containing a ring structure (110), including an outer fairing (100) defining the outer aerodynamic surface, and an inner fairing (102) defining the inner aerodynamic surface, with said outer (100) and inner ( 102) the fairings are connected upstream by an air intake edge (108) forming a leading edge, wherein said inner fairing (102) contains an outer skin (114) attached to the air intake edge (108) by an upstream mounting flange (118), wherein said outer casing (114) is configured to be attached to the outer casing (116) of the fan via a downstream mounting flange (122), wherein the air intake (1) contains at least two separate acoustic panels (2, 2'), attached to the outer skin (114) and containing a perforated acoustic skin (200) and a cellular core (202), wherein said at least two acoustic panels (2, 2') are adjacent and overlapped with each other.
  2. 2. The nacelle air intake according to claim 1, characterized in that the upstream mounting flange (118) is made integral with the outer casing (114).
  3. 3. The nacelle air intake as claimed in any one of the preceding claims, wherein the upstream mounting flange (118) forms an angle of approximately 90° with the outer skin (114).
  4. 4. The nacelle air intake according to any of the preceding claims, characterized in that the outer skin (114) is made of a composite material.
  5. 5. The nacelle air intake according to any of the preceding claims, characterized in that the acoustic panel (2) is attached to the outer skin (114) in a removable manner.
  6. 6. The nacelle air intake according to any one of paragraphs. 1-5, characterized in that the acoustic panel (2) is made of metal material.
  7. 7. The nacelle air intake according to claim 6, characterized in that the cellular core (202) is attached to the perforated acoustic lining (200) by soldering.
  8. 8. The nacelle air intake according to claim 1, characterized in that at least one of the acoustic panels includes an overlapping strip (201') configured to overlap an adjacent acoustic panel.
  9. 9. The nacelle air intake according to any of the previous paragraphs, characterized in that at least one movable hatch (4) is located on the annular structure (110).
  10. 10. Power plant (5), containing an air intake (1) according to any one of paragraphs. 1-9 and a fan (136) containing a plurality of fan blades (126), characterized in that the outer skin (114) of the air intake, on which at least one acoustic panel (2) is attached, has a shape diverging from the edge (108) air intake to the fan blades (126), wherein the power unit (5) has a radial gap (r) between the outer skin (114) and the fan blades (126), formed by removing at least one acoustic panel (2).
  11. 11. A method for removing a power plant fan blade (5) according to claim 10, including the steps of:
  12. - remove at least one separate acoustic panel (2) attached to the outer skin (114) so as to form a radial gap (r);
  13. - move the fan blade to be removed in accordance with the axial displacement (a) in the direction of the edge of the air intake (108), allowed by the radial clearance (r).
  14. 12. The method according to claim 11, characterized in that it includes the step of rotating the fan so as to position the fan blade to be removed opposite the removed acoustic panel.
  15. 13. Method according to any one of paragraphs. 11 or 12, characterized in that the acoustic panel (2) is attached to the outer skin (114) using mounting flanges (208, 210), the method including the step of removing the movable hatch (4) from the annular structure (110) for access to the mounting flanges (208, 210) of the acoustic panel (2).

Description

The present invention relates to the air intake of a nacelle of a turbomachine, such as a turbojet engine or turboprop engine of an aircraft. The aircraft is propelled by one or more power units, each of which contains a turbojet/turboprop engine housed in a tubular nacelle. Each powerplant is attached to the aircraft by a pylon, usually located under the wing or on the fuselage. The nacelle typically has a tubular structure comprising an upstream section forming an air intake upstream of the engine, a middle section enclosing the turbojet engine fan, and an aftstream section configured to accommodate thrust reversing means designed to surround the turbojet combustion chamber. engine and usually ending in an exhaust nozzle, the outlet of which is located downstream of the turbojet engine. The air intake is designed to optimize the capture of air needed to feed the turbojet engine fan in all flight modes and to direct the air towards the fan. The air intake essentially includes an air intake edge forming a leading edge attached to the annular structure. The annular structure contains an outer fairing providing external aerodynamic continuity of the nacelle, and an inner fairing providing internal aerodynamic continuity of the nacelle, in particular with an external fan casing in the middle section. The air intake lip provides a downstream connection between these two fairings. The inner fairing of the air intake is exposed to a strong air flow and is located near the fan blades. Consequently, it contributes to the propagation of noise emanating from the turbojet engine to the outside of the aircraft. It is also known in the prior art to equip the inner fairing of the nacelle air intake with an acoustic panel to reduce the transmission of noise generated by a turbojet engine. Typically, an acoustic panel includes a perforated acoustic skin and a cellular core that is assembled onto the acoustic skin. The cellular core includes a plurality of acoustic cells forming Helmholtz resonators, which are separated from each other by peripheral partitions. The perforated lining is directed toward the noise-emitting area so that acoustic waves can penetrate through the holes in the perforated lining into the acoustic cells. Acoustic energy is dissipated inside the acoustic cells due to the viscous-thermal effect. The cellular core of an acoustic panel can be one cell thick or two thicknesses separated by a micro-perforated partition to improve the acoustic performance of the panel. In addition to the noise reduction function, these panels provide two more functions: - aerodynamic function: the perforated skin is in contact with the air and gas flows circulating through the turbojet engine, and the nacelle directs the flow and should disrupt these flows as little as possible; - load-bearing function of absorbing forces: the acoustic panel is capable of absorbing some forces acting on the gondola. The disadvantage of prior art acoustic panels is that they are difficult to maintain and repair, for example in the event of damage caused by bird strikes, foreign bodies, etc. Another disadvantage is the aerodynamic losses that can be caused by the perforations of the acoustic lining, which are often poorly made, interfere with the proper operation of the air intake and lead to reduced engine performance. To limit these aerodynamic losses, the cross-section of such perforations should be reduced as much as possible. Another disadvantage is that the treated surface of the acoustic panels cannot be optimally used in comparison with the existing air intake surface, while the acoustic panels are usually reinforced with load-bearing reinforcing elements to satisfy the requirement of force transmission where acoustic perforation is ineffective or even impossible. Another disadvantage is the cost of manufacturing these acoustic panels, particularly double cell thickness panels, which require additional manufacturing steps and are more expensive to manufacture. Another disadvantage is the difficulty in removing the fan blades in so-called short-inlet designs, which have an overall truncated cone geometry. This design is optimal from an aerodynamic point of view, but it complicates the removal of the blade, since the axial translational movement of the fan blade towards the edge of the air intake leads to a collision with the air intake. The invention is particularly directed to eliminating at least one of these disadvantages and problems and relates, according to a first aspect, to an air intake for a nacelle of a turbojet engine comprising an annular structure including an outer fairing defining an outer aerodynamic surface and an inner fairing defining an inner aerodynamic surface, wherein said outer and inner fairings are connected upstream by an air intake edge forming a leading edge, said inner fairing comprises an outer skin attached to the edge of the air intake by a downstream mounting flange, wherein said outer skin is configu