Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
  • F02C7/04—Air intakes for gas-turbine plants or jet-propulsion plants
  • F02C7/045—Air intakes for gas-turbine plants or jet-propulsion plants having provisions for noise suppression
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
  • F02C7/04—Air intakes for gas-turbine plants or jet-propulsion plants
  • F02C7/047—Heating to prevent icing
• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
  • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
  • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
  • G10K11/172—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using resonance effects
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
  • B64D33/00—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for
  • B64D33/02—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes
  • B64D2033/0206—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes comprising noise reduction means, e.g. acoustic liners
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2230/00—Manufacture
  • F05D2230/60—Assembly methods
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2250/00—Geometry
  • F05D2250/20—Three-dimensional
  • F05D2250/28—Three-dimensional patterned
  • F05D2250/282—Three-dimensional patterned cubic pattern
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2250/00—Geometry
  • F05D2250/20—Three-dimensional
  • F05D2250/28—Three-dimensional patterned
  • F05D2250/283—Three-dimensional patterned honeycomb
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2250/00—Geometry
  • F05D2250/30—Arrangement of components
  • F05D2250/32—Arrangement of components according to their shape
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2250/00—Geometry
  • F05D2250/60—Structure; Surface texture
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2250/00—Geometry
  • F05D2250/70—Shape
  • F05D2250/71—Shape curved
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

• the present invention relates to a process for producing a coating for acoustic treatment incorporating a honeycomb structure with a complex shape, said coating being more particularly adapted to cover a leading edge of an aircraft, in particular an air intake. air of a nacelle.
• a coating for acoustic treatment incorporating a honeycomb structure with a complex shape
• said coating being more particularly adapted to cover a leading edge of an aircraft, in particular an air intake. air of a nacelle.
• a coating for acoustic treatment also called acoustic panel, comprises from the outside to the inside an acoustically resistive porous layer, at least one honeycomb structure and a reflective or impermeable layer.
• the acoustically resistive porous layer is a porous structure having a dissipative role, partially transforming the acoustic energy of the sound wave passing through it into heat. It includes so-called open zones capable of passing acoustic waves and other so-called closed or full not allowing the sound uncles but intended to ensure the mechanical strength of said layer.
• This acoustically resistive layer is characterized in particular by an open surface area which varies essentially according to the engine, the components constituting said layer.
• the honeycomb structure is delimited by a first imaginary surface at which the acoustically resistive porous layer is directly or indirectly reportable and by a second imaginary surface at which the reflective layer can be directly or indirectly reported. and comprises a plurality of ducts opening on the one hand at the first surface and secondly on the second surface. These ducts are closed by the acoustically resistive porous layer on the one hand and the reflective layer on the other hand so as to form a cell.
• a honeycomb structure is used to form the honeycomb structure of a coating for acoustic treatment. Different types of materials can be used to form the honeycomb.
• a honeycomb is obtained from strips disposed in a vertical plane extending in a first direction, each strip being alternately connected to the adjacent strips with a spacing between each bonding zone.
• a honeycomb panel is obtained, the strips forming the side walls of the hexagonal section ducts.
• a honeycomb structure may comprise a first series of rectangular strips and a second series of rectangular strips each comprising cutouts for assembling them so as to form a planar honeycomb structure.
• the complex In the case of a coating for the acoustic treatment, the complex is made flat, namely the acoustically resistive and reflective porous layers are connected to the honeycomb structure in a planar configuration. Subsequently, the complex is shaped at the surface to be treated. In the case of a flat wall or a cylindrical wall of a nacelle of large diameter, this shaping can be performed. It is different for small diameter pipes or complex surfaces, for example with two radii of curvature as an air inlet of a nacelle.
• the honeycomb structure when the honeycomb structure is curved according to a first radius of curvature oriented upwards and disposed in a first plane, this tends to cause a radius of curvature oriented downwards and arranged in a plane substantially perpendicular to the first, the honeycomb structure in the form of a horse saddle or a hyperbolic paraboloid.
• the existing solution would not be satisfactory because the shaping causes random deformation of the side walls of the ducts of the honeycomb structure so that it is difficult to determine the positioning said side walls of the ducts, the latter being concealed by the reflector and acoustically resistive layers.
• the extent of acoustically treated surfaces is limited inside the ducts of the nacelle, said treated surfaces not extending at the lip of the entrance of the nacelle. air of a nacelle.
• the present invention aims at overcoming the disadvantages of the prior art, by proposing a method of producing a coating for acoustic treatment incorporating a cellular structure enabling said coating to be shaped according to a complex surface without altering its properties. mechanical characteristics, said coating having a simple design and manufacturing costs adapted to the market.
• the subject of the invention is a method for producing a coating for the acoustic treatment reported at the level of a surface to be treated of an aircraft, in particular at a leading edge such as a air intake of an aircraft nacelle, said coating for the acoustic treatment including from inside to outside a reflective layer, a cellular structure and an acoustically resistive layer, characterized in that it consists of:
• first bands being intersecting with the second strips so as to delimit a duct between first two adjacent strips and second two adjacent strips, - cut each strip according to their previously defined geometries
• the honeycomb structure of the invention is not deformed once it is assembled.
• FIG. 1 is a perspective view of a propulsion assembly of an aircraft
• FIG. 2 is a longitudinal section illustrating an air inlet of a nacelle comprising a coating for the acoustic treatment according to the invention
• FIG. 3 is an elevational view illustrating a longitudinal strip arranged in a radial plane
• FIG. 4A is an elevational view illustrating a first transverse strip disposed along a first secant surface at radial planes
• FIG. 5B is a perspective view illustrating the first strip illustrated in Figure 4A 1 - 5A is an elevational view illustrating a second transverse strip disposed in a second cutting surface to the radial planes, said second surface in the top part the lip of a nacelle air inlet,
• FIG. 5B is a perspective view illustrating the second band illustrated in FIG. 5A which can be bent to nest in the first bands,
• FIG. 6 is a perspective view illustrating a honeycomb structure according to the invention capable of being adapted to an angular sector of an air inlet
• FIG. 7 is a perspective view illustrating in detail the connection between a longitudinal strip and a transverse strip
• FIG. 8 is a view from above illustrating a coating according to the invention.
• FIG. 9 is a section illustrating a coating according to the invention.
• the present invention is now described applied to an air intake of a propulsion unit of an aircraft. However, it can be applied to the different leading edges of an aircraft or to the different surfaces of an aircraft at which an acoustic treatment is performed.
• FIG. 1 shows a propulsion unit 10 of an aircraft connected under the wing by means of a mast 12.
• This propulsion unit could be connected to other zones of the aircraft.
• This propulsion unit comprises a nacelle 14 in which is disposed substantially concentrically a drive driving a fan mounted on its shaft 16.
• the longitudinal axis of the nacelle is referenced 18.
• the nacelle 14 comprises an inner wall 20 delimiting a duct asec a air inlet 22 at the front, a first part of the incoming air flow, called primary flow, passing through the engine to participate in combustion, the second part of the air flow, called secondary flow, being driven by the blowing and flowing in an annular conduit defined by the inner wall 20 of the nacelle and the outer wall of the engine.
• the upper part 24 of the air inlet 22 describes a substantially circular shape which extends in a plane which may be substantially perpendicular to the longitudinal axis 18, as shown in FIG. 2, or not perpendicular, with the portion summit at 12 o'clock slightly advanced.
• other forms of air intake can be envisaged.
• aerodynamic surface means the envelope of the aircraft in contact with the aerodynamic flow.
• this acoustic coating also called acoustic panel, comprises from inside to outside a reflector layer 28, a honeycomb structure 30 and an acoustically resistive layer 32.
• the acoustic coating may comprise several cellular structures 30 separated by acoustically resistive layers called septum.
• the reflective layer 28 may be in the form of a metal sheet or a skin consisting of at least one layer of woven or non-woven fibers embedded in a resin matrix.
• the acoustically resistive layer 32 may be in the form of at least one layer of woven or non-woven fibers, the fibers preferably being coated with a resin to ensure the recovery of forces in the different directions of the fibers.
• the acoustically resistive structure 32 comprises at least one porous layer in the form of, for example, a metallic or non-metallic fabric such as a Wiremesh and at least one structural layer per example a metal sheet or composite with oblong holes or microperforations.
• the reflective layer and the acoustically resistive layer are not more detailed because they are known to those skilled in the art.
• the honeycomb structure 30 corresponds to a volume defined on the one hand by a first imaginary surface 34 on which the reflective layer 28 is attached, and on the other hand by a second imaginary surface 36 on which the acoustically resistive layer 32 is attached, such as shown in Fig. 6.
• the distance between the first imaginary surface 34 and the second imaginary surface 36 may not be constant. Thus this distance may be greater at the lip of the air inlet to give said structure a greater resistance including compression.
• the honeycomb structure 30 comprises on the one hand a plurality of first strips 38 called longitudinal strips corresponding to the intersection of the volume with radial planes incorporating the longitudinal axis 18, and secondly, a plurality of second bands 40 called strips. cross-sections corresponding to the intersection of the volume with secant surfaces at radial planes.
• each transverse strip 40 is substantially perpendicular to the tangent to the second imaginary surface 36 at the considered point.
• each longitudinal band 38 is substantially perpendicular to the tangent of each transverse strip 40 at the point in question.
• Secant surface means a plane or surface that is intersecting with the first imaginary surface 34 and the second imaginary surface 36. More generally, the honeycomb structure comprises a series of first strips 38 disposed at intersecting surfaces, said first strips 38 being non-intersecting and spaced apart from each other, and at least a second series of second strips 40 arranged at the level of intersecting surfaces, said second strips 40 being non-intersecting and spaced apart from each other.
• the first bands 38 are intersecting with the second bands so as to delimit a duct between two adjacent first strips and second two adjacent strips.
• the first bands in radial planes containing the longitudinal axis of the nacelle.
• the second strips will be arranged so that they are substantially perpendicular to the first strips in order to obtain ducts with square, rectangular sections.
• This solution also simplifies the design.
• the sections of the conduits are evolutionary. Thus, they vary between a large section at the second imaginary surface 36 and a smaller section at the first imaginary surface 34.
• first cutouts 42 are provided at the level of the longitudinal strips 38 which cooperate with second cutouts 44 at the level of the transverse strips 40.
• the first and second cutouts 42 and 44 do not extend from one edge to the other to facilitate assembly.
• the length of the first blanks 42 and the second blanks 44 are adjusted so that the edges of the longitudinal and transverse strips are arranged at the imaginary surfaces 34 and 36.
• the first blanks 42 extend. from the edge of the longitudinal strips disposed at the second imaginary surface 36.
• the second cutouts 44 extend from the edge of the transverse strips disposed at the first imaginary surface 34.
• the shape of the alveolar structure 30 that it will have when it is in place at the level of the surface to be treated is digitized. The longitudinal and transverse strips are then positioned virtually in order to define for each of them their geometries.
• the longitudinal strips 38 have a C shape with a first edge 46 likely to correspond with the first imaginary surface 34 and a second edge 48 capable of correspond to the second imaginary surface 36.
• the distance between the edges 46 and 48 may vary from one band to another or along the profile of the same band.
• the longitudinal strips 38 are cut in substantially flat plates. This flat cut simplifies manufacturing.
• the shapes of the imaginary surfaces 34 and 36 are derived from the shapes of the edges 46 and 48 which are generated by cutting and not by deformation which guarantees a greater dimensional accuracy of said imaginary surfaces.
• the transverse strips 40 have ring shapes with a first edge 50 likely to correspond with the first imaginary surface 34 and a second edge 52 may correspond with the second imaginary surface 36.
• the edges 50 and 52 have a radius of curvature that can vary progressively as a function of the distance from the top portion 24, from a value R substantially corresponding to the radius of curvature of the duct forming the nacelle for the transverse bands 40, as illustrated in FIG. 4A, and an infinite radius, the edges 50 and 52 being substantially rectilinear, for the transverse band 40 disposed at the level of the upper part 24 of the air inlet as shown in FIG. 5A.
• the transverse strips 40 are cut in substantially flat plates.
• An advantage of the invention lies in the fact that the transverse and longitudinal strips are cut flat which contributes to simplify the manufacture and they do not undergo any forming operation which guarantees the adjustment of the cells on the refective layer and the acoustically resistive layer.
• the transverse bands depending on their position, are sufficiently flexible to be optionally curved so as to nest in the longitudinal strips.
• the transverse strips 40 disposed in areas of the honeycomb structure having a single radius of curvature, including substantially cylindrical portions are arranged in planes once assembled. Most of the transverse strips 40 are sufficiently flexible to be optionally curved along a radius of curvature r perpendicular to the surface of the strips, as shown in FIG.
• the transverse bands 40 remote from the summit portion 24 are not curved, which corresponds to a radius of infinite curvature r, the transverse strips 40 having a radius of curvature r which decreases progressively as a function of the distance separating the transverse band considered from the summit portion 24 to a radius r substantially equal to the radius of the summit portion for the transverse strip 40, illustrated in Figures 5A and 5B, disposed at the top portion 24.
• the strips are no longer deformed once assembled or when the reflective or acoustically resistive layers are put in place.
• the acoustic coating thus formed having shapes adapted to those of the surface to be treated, it is no longer deformed when it is placed at the level of said surface to be treated. Therefore, unlike the prior art, the connection between the honeycomb structure and the reflective layer or the acoustically resistive layer is no longer likely to be damaged and the position of the walls of the ducts that correspond to the strips is perfectly known and corresponds to the desired position when scanning.
• the strips 38 and 40 may be made of cardboard, metal (titanium, aluminum alloy steel), composite (glass fibers for example).
• the materials used can be mixed, for example using glass fibers for the longitudinal strips and titanium for the transverse strips.
• the metal will be chosen to give the structure good impact resistance, in particular impact to the bird.
• the assembly of the strips can be manual or robotic. As illustrated in FIG. 7, the longitudinal strips 38 and the transverse strips 40 are assembled and then joined together by welding, for example a solder 54, or by gluing.
• welding for example a solder 54
• other solutions to provide a link between the bands can be envisaged.
• the portions of the honeycomb structure disposed in line with the lip have a thickness greater than the parts of the honeycomb structure remote from said lip.
• the edges of the strips can have more complex shapes and include several radii of curvature in order to obtain more complex surfaces.
• the first cuts 42 'and 42 "consecutive may have a smaller gap to obtain a small spacing between the transverse strips 40' and 40" consecutive as shown in Figure 6.
• the second cutouts 44 'and 44 "consecutive may have a smaller gap to obtain a small gap between the longitudinal strips 38, 38" consecutive as shown in Figure 6.
• This arrangement makes it possible to obtain cells with variable sections.
• the strips 38 and 40 may comprise cutouts 56 for making certain cells communicate with each other and obtain a network of conduits.
• This solution makes it possible to generate a network of conduits, provided between the closely spaced adjacent strips 38 and 40, used to convey hot air and obtain the frost treatment function.
• the non-communicating cells are used for the function of the acoustic treatment.
• the acoustically resistive layer 32 comprises at least one skin with open areas 58 allowing the sound waves to pass and full areas 60 not allowing the sound waves to pass.
• the shape, the dimensions, the number, the arrangement of the open zones 58 are adjusted so as to optimize the acoustic treatment by minimizing the disturbances in the aerodynamic flow flowing on the surface of the acoustically resistive layer.
• the open zones 58 may have an oblong shape, the largest dimension of which is arranged in the direction of flow of the aerodynamic flow.
• an open zone 58 comprises a single orifice whose shape corresponds to that of the open zone or a plurality of slightly spaced holes or microperforations covering said open zone.
• the acoustically resistive structure 32 comprises at least one porous layer in the form of, for example, a metallic or non-metallic fabric such as a Wiremesh and at least one structural layer, for example a metal or composite sheet with open areas 58.
• the acoustically resistive layer may comprise other holes, perforations or microperforations for the treatment of hot air frost, for example.
• the acoustically resistive layer 32 is produced by arranging the open zones 58 as a function of the position of the side walls 38 and 40 of the cellular structure 30.
• the open zones 58 are made, the acoustically resistive layer 32 is deposited on a preform whose shapes correspond to those of the surface of the honeycomb structure 30 on which said acoustically resistive layer 32 must be placed in order to obtain a better positioning of the open zones 58.
• the acoustically resistive layer 32 and the honeycomb structure 30 are made, they are assembled by any appropriate means.
• the honeycomb structure is metallic and the acoustically resistive layer 32 comprises a wiremesh 62 disposed between two structural metal layers 64, one of the two structural layers 64 being connected to the honeycomb structure by welding or gluing.
• the acoustically resistive layer consists of a bone sheet / ec of microperforations at the open zones 58. According to the invention, a perfect positioning of the open zones 58 with respect to the side walls 38 and 40 of the structure is obtained. alveolar 30, said open areas 58 never being arranged in line with a side wall but at the right of a cell. Thus, the operation of the opening is always optimal for the acoustic treatment.
• the open area ratio is determined as accurately as possible without providing a margin of error due to a bad positioning of the open areas relative to the side walls.
• the acoustically resistive layer of the invention is also optimal in terms of aerodynamic characteristics insofar as the planned open zones ensure optimum operation in terms of acoustic treatment, none of which are provided at the right of a side wall. .

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• 2008
  • 2008-02-14 CA CA2678476A patent/CA2678476A1/fr not_active Abandoned
  • 2008-02-14 BR BRPI0807276-0A patent/BRPI0807276A2/pt not_active IP Right Cessation
  • 2008-02-14 EP EP08762096A patent/EP2140120A2/de not_active Withdrawn
  • 2008-02-14 JP JP2009549456A patent/JP2010519445A/ja active Pending
  • 2008-02-14 RU RU2009134984/06A patent/RU2455510C2/ru not_active IP Right Cessation
  • 2008-02-14 WO PCT/FR2008/050248 patent/WO2008104716A2/fr active Application Filing
  • 2008-02-14 US US12/527,984 patent/US20100089690A1/en not_active Abandoned

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