Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
  • F01D25/24—Casings; Casing parts, e.g. diaphragms, casing fastenings
• • 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
  • B64D29/00—Power-plant nacelles, fairings, or cowlings
• • 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

Definitions

• the air inlet section comprises firstly a cover having an outer wall and an air inlet lip, the lip being adapted to allow optimal capture to the turbojet of the air necessary for feeding the blower and the internal compressors of the turbojet, and secondly a fixed ferrule which comprises an acoustic panel and which is intended to properly channel the air to the blades of the blower.
• the element, and the blade are made of a material that is both capable of being elastically deformed, so as to obtain the appropriate veneer of the element against the lip and the ferrule and also sufficiently rigid so that the element has the mechanical strength appropriate to the stresses to which it is subjected.
• the blade may be made of a composite material or reinforcement fabric impregnated with silicone.
• the end blade has a thickness less than the thickness of the other parts of the element. This limits the aerodynamic impact of the downstream portion of the element.
• the blade has a thickness of less than 0.75 mm.
• the end blade may be substantially flat, or curved with a concavity facing outward. The function of the curvature is to resume the leverage created by the bead that takes the compression efforts.
• the equipressure means comprise, for example, radially through orifices provided in the element and / or axial passages formed in the annular bead. In the latter case, there is then an interrupted bead, presenting itself as a succession of pads on the periphery of the element.
• the annular bead may be substantially continuous.
• the element is for example made of composite material which may comprise at least one substantially continuous reinforcement on its periphery.
• the constraints related to the compression of the element - during displacement relative to the ferrule or during installation on the nacelle - and in particular the buckling, are taken up by the composite.
• the upstream end of each slot opens into a circular orifice, in order to prevent crack initiation at the end of the slot.
• the attachment points of the element on the lip are preferably located downstream of these circular holes so as not to fatigue fatigue said orifices.
• the element is made of a flexible material. In other words, it is possible to make such an element whose flexibility is not due to the presence of slits but to the only appropriate choice of the material constituting it.
• the element can be made from at least two substantially identical strips rolled on themselves and fixed end to end along axial lines to form together a generally cylindrical general shape. Typically, one can provide two strips each forming a half cylinder.
• the invention relates to an aircraft nacelle comprising on the one hand a fixed ferrule and on the other hand an axially movable entry lip with respect to the ferrule, between a rear operating position and a forward position. of maintenance.
• Figure 3 is a schematic vertical sectional view of the upstream section of the nacelle of Figures 1 and 2;
• Figure 4 is a sectional view of an element according to a first embodiment of the invention.
• Figure 8 is a perspective view of an element according to a third embodiment of the invention.
• the nacelle 1 is equipped with an element 15 intended to ensure aerodynamic continuity between the lip 8 and the shell 9, in the rear operating position.
• the element 15, in the mounted position has a generally cylindrical general shape. It comprises :
• the element 15 comprises on the one hand an outer face 22 and on the other hand an inner face 23, turned towards the axis 10 of the nacelle 1 in the mounted position, which is substantially cylindrical without extra thicknesses and without protruding parts, so that provide a generally smooth surface to improve aerodynamic continuity and optimize airflow.
• the upstream portion 16 of the element 15 has a thickness greater than that of the intermediate portion 19.
• the upstream portion 16 constitutes the zone of attachment of the element 1 5 to the nacel 1 and must therefore be able to ten ir corresponding contra intes, tand is that the intermediate portion 1 9 serves essentially to cover the interface between the lip 8 and the ferrule 9.
• the thickness of the upstream portion 1 6 is between 2 and 6mm, and The thickness of the intermediate portion 19 is between 1 and 3 mm.
• the downstream portion 20 comprises an annular bead 24 projecting from the outer face 22 and an end plate 25 of reduced thickness, typically less than 0.75 mm. At rest, that is to say when the element 15 is not deformed, the blade 25 is inclined outwards towards its free end.
• the inner wall 18 of the lip 8 comprises a recess 26 formed by an axially inward recoil step.
• the ferrule 9 also has a recess 27 formed by an inwardly axial recessed step adjacent to an upstream chamfer 28 and a downstream chamfer 29.
• the nacelle 1 is designed so that the upstream portion 30 of the inner wall 18 of the lip 8 and the downstream portion 31 of the shell 9 are substantially of the same diameter.
• the upstream portion 16 of the element 15 is housed in the recess 26 of the lip, while the bead 24 is housed in the recess 27 of the shell 9 and that the end plate 25 bears against the downstream portion 31 of the ferrule 9.
• a peripheral face of the substantially cylindrical air stream is obtained which makes it possible to optimize the flow of air, and all the more so since the thickness of the blade 25 is relatively weak.
• the element 15 is flexible, which allows it to be plated, by elastic deformation, against the shell 9. It can be expected that the element 15 is slightly divergent downstream at rest, to improve the veneer against the ferrule 9.
• the strip 32 is not perfectly flat but slightly curved outwards from its upstream portion 16 towards its downstream portion 20, so as to form a slightly divergent element downstream, which will favor its plating against the shell 9.
• the end plate 25 is here curved in the extension of the rest of the strip 32, with its concavity facing outwardly.
• the blade 25 may be substantially flat but inclined outwards.
• the outer layer 33 of the strip 32 forms the entire end plate 25, and no longer only a cover layer.
• the blade 25 comprises longitudinal slots extending from its free end to the bead 24. These slots 35 can increase the deformation capacity of the blade 25 and avoid detachment of the blade 25, in order to improve the veneer of the blade 25 against the ferrule 9.
• FIG. 8 there is no longer a continuous annular bead 24, but a discontinuous bead, forming a succession of separate pads 36 along the blade 25.
• a discontinuous bead forming a succession of separate pads 36 along the blade 25.
• axial passages 37 which allow, in operation, to equipress the inner and outer sides of the element 15.
• the upstream end of the slots 39 opens into a circular orifice 40, which makes it possible to prevent or considerably limit the crack initiators at the end of the slot.
• the openings 34 for fastening the strip 32 to the lip 8 are located downstream of these circular orifices 40 so as not to fatigue the said orifices 34.
• the element 15 is substantially tangential to the lip 8 and the shell 9 against which it bears radially.
• the element is designed to allow the opening and closing of the cover without dismantling part, and to be able to withstand these successive displacements during many cycles, for example of the order of 3500 cycles.
• the presence of the blade 25 makes it possible to compensate for the axial and radial positioning offsets between the lip 8 and the shell 9 by providing a covering means pressed against the shell 9.
• the blade 25 further allows the adaptation of the element 15 to the shapes and tolerances of the lip 8 and the ferrule 9.
• the band according to the first embodiment could comprise means of putting in equipression, that the strip of the strip of FIG. 8 could be curved, that the bead of FIG. 7 could be discontinuous, etc.
• the invention provides a decisive improvement to the prior art, by providing an element allowing the aerodynamic optimization of the interface between the downstream edge of a LFC-type hood air intake lip and the acoustic shroud. extending between this edge and the fan casing.

Applications Claiming Priority (2)

Publications (1)

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• 2010
  • 2010-05-19 FR FR1053855A patent/FR2960216B1/fr active Active
• 2011
  • 2011-05-09 RU RU2012151437/11A patent/RU2571981C2/ru not_active IP Right Cessation
  • 2011-05-09 CN CN2011800246256A patent/CN103003151A/zh active Pending
  • 2011-05-09 BR BR112012028905A patent/BR112012028905A2/pt not_active IP Right Cessation
  • 2011-05-09 WO PCT/FR2011/051043 patent/WO2011144836A2/fr active Application Filing
  • 2011-05-09 EP EP11725142A patent/EP2571765A2/fr not_active Withdrawn
  • 2011-05-09 CA CA2798482A patent/CA2798482A1/fr not_active Abandoned
• 2012
  • 2012-11-19 US US13/681,219 patent/US8939713B2/en not_active Expired - Fee Related

Non-Patent Citations (1)

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