TURBOJET ENGINE COMPRISING A NACELLE WITH AN AIR INTAKE TO PROMOTE A REVERSED THRUST PHASE

Abstract

An aircraft turbojet engine extending along an X axis and comprising a blower configured to provide a reverse thrust and a nacelle comprising an air intake which comprises at least one deflection member movably mounted between a deployed position in which the deflection member projects from the inner wall or from the lip of the air intake in a radially inward direction of deployment facing the X axis or in a longitudinal direction of deployment with respect to the X axis, in order to allow a release of the reverse air flow from the inner wall to support the reverse thrust phase, and a retracted position in which the air intake has an aerodynamic profile so as to guide the internal air flow along the inner wall in order to support the thrust phase.

Claims

1-12. (canceled)

13. An aircraft turbojet engine extending along an axis X oriented from upstream to downstream in which an internal air flow circulates from upstream to downstream during a thrust phase and a reverse air flow from downstream to upstream during a thrust reversal phase, said turbojet engine comprising a fan configured to provide reverse thrust and a nacelle comprising an air intake, the air intake circumferentially extending about axis X and comprising an internal wall pointing to axis X and configured to guide the internal air flow and the reverse air flow, and an external wall opposite to the internal wall and configured to guide an external air flow, the internal wall and the external wall being connected to each other by an air intake lip so as to form an annular cavity, the air intake comprising a deflection device comprising at least one deflection member movably mounted between an extended position, in which the deflection member projectingly extends from the internal wall or from the air intake lip in a radially internal extension direction pointing to axis X or a longitudinal extension direction relative to axis X in order to allow a separation of the reverse air flow from the internal wall to promote the thrust reversal phase, and a retracted position, in which the air intake has an aerodynamic profile so as to guide the internal air flow onto the internal wall to promote the thrust phase.

14. The aircraft turbojet engine according to claim 13, wherein the extension direction is oriented upstream.

15. The aircraft turbojet engine according to claim 13, wherein, with the annular cavity extending along a longitudinal direction X20 substantially parallel to axis X and the extension direction forming an extension angle with respect to the longitudinal direction X20, the extension angle is between 90° and 140°.

16. The aircraft turbojet engine according to claim 13, wherein the deflection device comprises a plurality of deflection members distributed at the circumference of the air intake about axis X.

17. The aircraft turbojet engine according to claim 13, wherein the deflection device comprises at least one row comprising a plurality of deflection members at a same radial distance from axis X.

18. The aircraft turbojet engine according to claim 13, wherein the deflection device comprises a single deflection member circumferentially extending about axis X.

19. The aircraft turbojet engine according to claim 13, wherein at least one deflection member is rotatably hinged between the extended position and the retracted position.

20. The aircraft turbojet engine according to claim 13, wherein at least one deflection member is translationally mounted along the extension direction between the extended position and the retracted position.

21. The aircraft turbojet engine according to claim 13, wherein the deflection device comprises at least one controllable active moving member in order to move the deflection member from the retracted position to the extended position.

22. The aircraft turbojet engine according to claim 13, wherein the deflection device comprises at least one passive moving member configured to move the deflection member from the retracted position to the extended position under the action of the reverse air flow.

23. The aircraft turbojet engine according to claim 13, wherein the deflection device comprises a cover member movably mounted between a covered position, in which said cover member covers the deflection member in the retracted position so as to provide an aerodynamic profile, and an uncovered position, in which said cover member is offset from its covered position so as to bring the deflection member to the extended position.

24. A method for operating the aircraft turbojet engine according to claim 13, wherein at least one deflection member is in the retracted position during a thrust phase of the turbojet engine, so that the air intake has an aerodynamic profile so as to guide the internal air flow onto the internal wall, the method comprising, during a thrust reversal phase of said turbojet, a step of moving the deflection member into an extended position so that said deflection member projectingly extends from the internal wall or from the air intake lip along a radially internal extension direction pointing to axis X or a longitudinal extension direction relative to axis X, in order to allow separation of the reverse air flow from the internal wall to promote the thrust reversal phase.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The invention will be better understood upon reading the following description, given only by way of example, and referring to the appended drawings given as non-limiting examples, in which identical references are given to similar objects and in which:

[0042] FIG. 1 is a schematic representation in a longitudinal cross-section view of a turbojet engine nacelle in thrust phase, according to prior art,

[0043] FIG. 2 is a schematic representation in a longitudinal cross-section view of a turbojet engine nacelle in thrust reversal phase, according to prior art,

[0044] FIG. 3 is a schematic representation in a longitudinal cross-section view of a turbojet engine nacelle in the thrust reversal phase, according to the invention,

[0045] FIG. 4 and

[0046] FIG. 5 are a schematic representation in a transverse cross-section view of an air intake comprising a deflection device comprising one or two rows,

[0047] FIG. 6 is a schematic representation in a transverse cross-section view of an air intake comprising a deflection device with a circumferential deflection member,

[0048] FIG. 7A and

[0049] FIG. 7B are a schematic representation in a longitudinal cross-section view of an air intake comprising a deflection device, according to a first embodiment of the invention with an active moving member, in an extended position and a retracted position,

[0050] FIG. 7C and

[0051] FIG. 7D are a schematic representation in a longitudinal cross-section view of an air intake comprising a deflection device, according to a first embodiment of the invention with passive moving member, in the extended position and in the retracted position,

[0052] FIG. 8A and

[0053] FIG. 8B are a schematic representation in a longitudinal cross-section view of an air intake comprising a deflection device, according to a second embodiment of the invention, in the extended position and in the retracted position,

[0054] FIG. 8C is a schematic representation in a longitudinal cross-section view of an air intake comprising a deflection device in the retracted position with another cover member,

[0055] FIG. 9A and

[0056] FIG. 9B are a schematic representation in a longitudinal cross-section view of an air intake comprising a deflection device, according to a third embodiment of the invention, in the extended position and the retracted position,

[0057] FIG. 10A and

[0058] FIG. 10B are a schematic representation in a longitudinal cross-section view of a turbojet engine nacelle allowing heterogeneous thrust reversal phase, according to the invention, and

[0059] FIG. 10C is a schematic representation in a transverse cross-section view of an air intake allowing heterogeneous thrust reversal phase, according to the invention.

[0060] It should be noted that the figures set out the invention in detail to implement the invention, said figures of course being able to be used to better define the invention if necessary.

DETAILED DESCRIPTION

[0061] With reference to FIG. 3, a turbojet engine 1 according to the invention is represented, extending along an axis X oriented from upstream to downstream and comprising a fan 11 rotatably mounted about axis X in an external shell 12 defining an air stream. In a known manner, the fan 11 is configured, during a thrust phase, to accelerate an air stream circulating from upstream to downstream in the turbojet engine 1, known as the internal air flow F-INT, and during a thrust reversal phase, to accelerate an air flow circulating from downstream to upstream in the turbojet engine 1, known as the reverse air flow F-INV.

[0062] In practice, as illustrated in FIG. 3, the reverse air flow F-INV circulates from downstream to upstream in a radially external portion of the air stream, in particular, over ⅓ of the radius of the air stream. An internal air flow F-INT always circulates from upstream to downstream in a radially internal portion of the air stream, in particular, over ⅔ of the air stream radius. The internal air flow F-INT ensures a sufficient flow rate to avoid any pumping phenomenon of the turbojet engine.

[0063] As illustrated in FIG. 3, the turbojet engine comprises a nacelle which comprises at its upstream end an air intake 2 circumferentially extending about axis X and comprising an internal wall 21, pointing to axis X and configured to guide the internal air flow F-INT and the reverse air flow F-INV, and an external wall 22, opposite to the internal wall 21 and configured to guide an external air flow F-EXT. The internal wall 21 and the external wall 22 are connected by an air intake lip 23 comprising a leading edge. The walls 21, 22 and the air intake lip 23 form an annular cavity 20 extending along a longitudinal direction parallel to axis X. Within the annular cavity 20, a sound attenuation device or a de-icing device may especially be mounted.

[0064] In this example, the turbojet engine 1 comprises thrust reversal means, in particular a variable pitch fan 11, or VPF, for reversing the air flow circulating in the turbojet engine 1 and thus to create a thrust reversal phase allowing the aircraft to decelerate during landing, or during any other maneuver.

[0065] According to the invention, with reference to FIG. 3, the air intake 2 comprises a deflection device comprising one or more deflection members 3, 4, 5 movably mounted between an extended position, adapted to improve thrust reversal, and a retracted position adapted to improve the thrust phase. Advantageously, in the extended position, the deflection member 3, 4, 5 projectingly extends from the internal wall 21 or the air intake lip 23 along a radially internal extension direction pointing to axis X or a longitudinal extension direction with respect to axis X, in order to allow a separation D of the reverse air flow F-INV from the internal wall 21 to favor the thrust reversal phase as illustrated in FIG. 3.

[0066] With reference to FIG. 3, preferably, in the extended position, the deflection member 3, 4, 5 projectingly extends from the internal wall 21 with respect to axis X. Advantageously, the deflection member 3, 4, 5 deflects the reverse air flow F-INV guided by the internal wall 21 in order to generate a separation D. In other words, the entire reverse air flow F-INV is guided so as to circulate in a substantially axial direction with respect to axis X in order to oppose an upstream air flow F, originating the thrust reversal phase. Preferably, as the extension direction forms an extension angle with respect to the longitudinal direction of the annular cavity 20, the extension angle of the deflection member 3, 4, 5 is between 90° and 140°. It is thus chosen to be sufficiently small to promote separation D and sufficiently large so as not to significantly reduce forces involved in the reverse air flow F-INV. It goes without saying, however, that the extension angle can be different, depending on the desired level of thrust reversal. In particular, the deflection member 3, 4, 5 may also projectingly extend downstream.

[0067] Hereinafter, a single deflection device is presented, but it goes without saying that the air intake 2 could comprise a plurality of deflection devices.

[0068] With reference to FIG. 4, a deflection device is represented, comprising several deflection members 3, 4, 5 which are distributed over the circumference of the air intake 2 about axis X in such a way as to enable the thrust reversal phase to be improved over the entire said circumference. In a preferred manner, with reference to FIG. 4, the azimuthal length of a deflection member 3, 4, 5 is such that these surfaces are of a low overall size, light and are easily extendable. Naturally, the azimuthal length may vary from one deflection member 3, 4, 5 to another, in order to adapt to different operating conditions, such as braking, and especially to cope with inhomogeneous air flow over the circumference of the air intake lip. Preferably, the azimuthal spacing between two consecutive deflection members 3, 4, 5 is sufficiently small so that the deflection members 3, 4, 5 cover a maximum azimuthal surface area when extended, or even partially overlap in the extended position. Preferably, the number of deflection members 3, 4, 5 is large enough to allow for a separation D over the entire circumference of the air intake 2 and small enough to reduce weight and drag.

[0069] Preferably, the deflection members 3, 4, 5 are organized as rows. Preferably, each row comprises a plurality of deflection members 3, 4, 5 at a same radial distance from axis X. In other words, a row is circular in shape. By way of example, a single circular row is represented in FIG. 4 and two circular rows in FIG. 5, but it goes without saying that the number of rows could be higher. The use of several rows, in particular staggered rows as illustrated in FIG. 5, allows a substantially continuous deflection to be achieved along the circumference of the air intake 2 while using deflection members 3, 4, 5 spaced apart from each other that are easier to maintain. In particular, the deflection members 3, 4, 5 may partially overlap in a scale-like manner to form a deflection continuity at the circumference of the air intake 2.

[0070] Preferably, with reference to FIG. 4, the ratio L3/L2, where parameter L3 is the radial thickness of a deflection member 3, 4, 5 and parameter L2 is the radial thickness of the air intake 2, is between 0.05 and 0.3.

[0071] Alternatively, with reference to FIG. 6, the deflection device comprises a single deflection member 3, 4, 5 circumferentially extending about axis X. Such a deflection member 3, 4, 5 is for ensuring deflection over the entire circumference of the air intake 2, during the thrust reversal phase.

[0072] Preferably, the deflection members 3, 4, 5 extend in the vicinity of the air intake lip 2 on the side of the internal wall 21 so as to avoid formation of a local depression zone.

[0073] Preferably, the material of a deflection member 3, 4, 5 is rigid so as to effectively improve the thrust reversal phase. Preferentially, this material is identical to that of the internal wall 21 and/or the external wall 22.

[0074] The invention will be better understood when describing the different embodiments. The different aspects of the invention are described hereinafter according to three embodiments, set forth successively and solely by way of example. It goes without saying that the invention is not limited to these three embodiments but encompasses any possible combination of the various technical characteristics of the embodiments set forth.

[0075] According to a first embodiment, with reference to FIGS. 7A and 7B, the deflection device comprises a row comprising a plurality of deflection members 3 positioned at the same radial distance from axis X. In this example, each deflection member 3 extends from the internal wall 21. Furthermore, in this example, each deflection member 3 comprises a proximal portion 31 rotatably hinged between the extended position A and the retracted position B and a distal portion 32 adapted to deflect the reverse air flow F-INV.

[0076] In this example, the distal portion 32 has a rectangular shape but of course other shapes could be suitable, especially a polygonal shape such as a trapezoidal shape. The trapezoidal shape has the advantage that with a single row of deflectors 3 of this type, the distal portions can cooperate together to continuously or substantially continuously cover the circumference of the air intake. The air flow is deflected over the entire circumference of the air intake. In other words, a staggered arrangement of the deflection members 3 is not necessary for the trapezoidal shape.

[0077] Preferably, since the fan 11 comprises fan vanes, the distal portion 32 has a length E3 less than ⅓ of the length of the fan vanes. Preferably, the proximal portion 31 is hinged at the internal wall 21 in the vicinity of the air intake lip 23.

[0078] In this example, as illustrated in FIG. 7A, the internal wall 21 comprises a concave housing 24, located upstream at the hinge axis with respect to the circulation direction of the reverse air flow F-INV and configured to receive the deflection member 3 in the retracted position B. As illustrated in FIG. 7B, in the retracted position B, the deflection member 3 extends as an extension of the internal wall 21 so that the air intake 2 has an aerodynamic profile.

[0079] In the example of FIG. 7A, the extension angle α formed between the longitudinal direction X20 of the annular cavity 20 and the extension direction X3, along which the deflection member 3 extends in the extended position A, is between 90° and 140°. It is thus chosen to be sufficiently low to promote separation D and sufficiently high so as not to significantly reduce forces involved in the reverse air flow F-INV. Its radially internal positioning makes it possible to act directly on the reverse air flow F-INV, which is advantageous.

[0080] As illustrated in FIG. 7A, in the extended position A, the reverse air flow F-INV generated by the fan 11 is guided by the internal wall 21 and then by the distal portion 32 of the deflection member 3 which moves the reverse air flow F-INV away from the air intake lip 23 in order to generate a separation D. This reduces the local vacuum exhibited in prior art, thereby improving the performance of the turbojet engine in the thrust reversal phase.

[0081] In this example, with reference to FIGS. 7A and 7B, the deflection device comprises a controllable active moving member 33 in order to move the deflection member 3 from the retracted position B to the extended position A. By way of example, this controllable active moving member 33 is in the form of a hydraulic, electric or other actuator in order to allow movement as a result of receiving a control command from a calculator. Preferably, the controllable active moving member 33 also allows the deflection member 3 to be moved from the extended position A to the retracted position B. Alternatively, the deflection member 3 can also be moved from the extended position A to the retracted position B passively under the effect of the internal air flow F-INT during the thrust phase.

[0082] It goes without saying that the deflection device 3 may comprise a plurality of controllable active moving members 33.

[0083] According to another example, with reference to FIGS. 7C and 7D, the deflection device comprises a passive moving member 34 in order to move the deflection member 3 from the retracted position B to the extended position A without resorting to an actuator.

[0084] In the example shown in FIGS. 7C and 7D, the passive moving member 34 is in the form of a conduit formed in the annular cavity 20 of the air intake 2. Preferably, the conduit comprises an inlet 34A opening into the internal wall 21 and an outlet 34B opening onto the deflection member 3 in the retracted position B. More precisely, the inlet 34A is located downstream of the deflection member 3 with respect to the orientation of axis X. The inlet 34A can be located either upstream or downstream of the fan. The outlet 34B in turn opens into the concave housing 24. Advantageously, the conduit allows the deflection member 3 to be moved under the effect of the force generated by a part F-INV1 of the reverse air flow F-INV circulating in the passive moving member 34.

[0085] Advantageously, the passive moving member 34 does not need to be supplied with energy and uses that of the reverse air flow F-INV to be moved into the extended position A during the thrust reversal phase and that of the internal air flow F-INT to be moved into the retracted position B during the thrust phase.

[0086] It goes without saying that the passive moving member 34 could have a different structure. It also goes without saying that a deflection device may comprise a plurality of passive moving members 34. Furthermore, a deflection device may comprise one or more passive moving members 34 and one or more controllable active moving members 33.

[0087] According to a second embodiment illustrated in FIGS. 8A, 8B, and 8C, a plurality of deflection members 4 that are translationally moved along the extension direction X4 are represented.

[0088] Preferably, the deflection members 4 have a polygonal, preferably trapezoidal, shape in order to have a high mechanical strength to oppose the reverse air flow F-INV. Analogously to the foregoing, each deflection member 4 extends from the internal wall 21 and has a proximal portion 41 and a distal air deflection portion 42. The proximal portion 41 extends into the annular cavity 20 while the distal portion 42 projectingly extends of the annular cavity 20 along a radially internal extension direction X4 pointing to axis X. Preferably, the length E4 of the distal portion 42 is less than ⅓ of the length of the fan vanes.

[0089] According to another aspect of the invention with reference to FIGS. 8A to 8C, the deflection device 4 comprises a cover member 44 movably mounted between a covered position C1, in which the cover member 44 covers the deflection member 4 in the retracted position B so as to provide an aerodynamic profile (FIG. 8B), and an uncovered position C2, in which the cover member 44 is offset from its covered position C1 (FIGS. 8A and 8C) so that the deflection member 4 is in the extended position A.

[0090] Preferably, the cover member 44 is made of a rigid material. Preferably, the cover member 44 is made of a material identical to the internal wall 21 and its shape is selected to be as an extension of the internal wall 21 so that the aerodynamic profile of the air intake 2 remains unchanged during the thrust phase.

[0091] In the example of FIG. 8A, the cover member 44 is translationally moved along the internal wall 21 inwardly, from the covered position C1 to the uncovered position C2. In the example of FIG. 8C, the cover member 44 comprises two parts positioned radially inwardly and radially outwardly of the deflection member 4 and rotatably hinged upstream of the air intake 2. However, it goes without saying that the cover member 44 could have other shapes and be moved in different ways. Furthermore, the cover member 44 may comprise one or more parts. Furthermore, the movement of the cover member 44 may be achieved by a controllable active moving member 43 and/or by a passive moving member or by any other moving member.

[0092] According to a third embodiment illustrated in FIGS. 9A and 9B, the deflection device comprises a single deflection member 5 circumferentially extending about axis X. Advantageously, the reverse air flow F-INV is deflected over the entire circumference of the air intake 2.

[0093] According to another aspect of the invention and as illustrated in FIGS. 9A and 9B, the deflection member 5 has a cylindrical shape and extends from the air intake lip 23 along an extension direction X5 substantially longitudinal to axis X. Preferably, the deflection member 5 allows the air intake lip 23 to be extended and thus to be reduced in thickness, thus promoting a separation D of the reverse air flow F-INV. Preferably, the deflection member 5 extends over a length E5 less than ⅓ of the length of the fan vanes.

[0094] Three particular embodiments of the invention have been described by way of example, but it goes without saying that the invention is not defined solely by these embodiments. Indeed, the invention encompasses any possible combination of the different technical characteristics of the embodiments set forth.

[0095] In particular, all three embodiments described have a deflection device for deflecting the reverse air flow F-INV homogeneously at the circumference of the air intake 2. However, under some operating conditions, such as braking, it may be advantageous to deflect this reverse air flow F-INV heterogeneously. Thus, various examples are described below with reference to FIGS. 10A to 10C for heterogeneously deflecting the reverse air flow F-INV.

[0096] As illustrated in FIG. 10A, a deflection member 3, 4, 5 can be oriented along different directions at the circumference of the air intake 2 so as to form an air intake lip oriented along a predetermined deformation axis AD. Alternatively, the deflection members 3, 4, 5 may extend along different projecting lengths at the circumference of the air intake 2, as illustrated in FIG. 10B. Furthermore, with reference to FIG. 10C, the deflection members 3, 4, 5 may form an elliptical-, in particular ovoid-shaped, row over the circumference of the air intake 2, in a plane transverse to axis X. In the case of a single deflection member 3, 4, 5, this can take the form of an elliptical belt in a plane transverse to axis X. A heterogeneous deflection advantageously makes it possible to guide the reverse air flow taking account of the environment of the air intake 2.

[0097] A method for operating the air intake 2 according to the invention previously set forth is described hereinafter.

[0098] During the thrust phase, the fan 11 makes it possible to accelerate an internal air flow F-INT which is guided by the air intake 2 having an aerodynamic profile promoting the thrust phase. The deflection member 3, 4, 5 is in the retracted position B during the thrust phase of the turbojet engine 1, so that the air intake 2 has an aerodynamic profile so as to guide the air flow.

[0099] During a thrust reversal phase of said turbojet engine 1, in particular following a change in the pitch of the fan vanes 11, the method comprises a step of moving the deflection member 3, 4, 5 from the retracted position B to the extended position A, during which, the deflection member 3, 4, 5 is extended so as to projectingly extend from the internal wall 21 or the air intake lip 23 along the radially internal extension direction X3, X4 pointing to axis X or the longitudinal extension direction X5 relative to axis X, promoting the thrust reversal phase. Advantageously, this movement step imparts to the aircraft a good performance both in the thrust phase, where the internal air flow F-INT is kept unchanged, and in the thrust reversal phase, where the deflection member 3, 4, 5 generates a separation D of the reverse air flow F-INV from the internal wall 21.

[0100] According to one aspect of the invention, only part of the deflection members 3, 4, 5 are moved during the movement step to adapt to different operating conditions, such as braking.

[0101] According to one aspect of the invention, the step of moving the deflection member 3, 4, 5 is performed by means of the controllable active moving device 33, 43 in a simple and quick manner. According to another aspect of the invention, the step of moving the deflection member 3, 4, 5 is performed by means of the passive movement device 34, judiciously using the force of the reverse air flow F-INV to move the deflection member 3, 4, 5 to the extended position A. Preferably, the passive movement device 34 uses the force of the internal air flow F-INT to move the deflection member 3, 4, 5 to the retracted position B.

[0102] Preferably, the operating method comprises a step of reversely moving the deflection member 3, 4, 5 from the extended position A to the retracted position B, during which, with the deflection member 3, 4, 5 initially extended in order to projectingly extend from the internal wall 21 or air intake lip 23 along the upstream and radially internal extension direction X3, X4 pointing to axis X or the longitudinal extension direction X5 relative to axis X promoting the thrust reversal phase, the deflection member 3, 4, 5 is moved so that the air intake 2 has an aerodynamic profile promoting the thrust phase. This movement can be carried out actively or passively.

[0103] By virtue of the invention, the performance of the turbojet engine 1 is significantly improved during the thrust reversal phase while maintaining the existing performance during the thrust phase. In fact, the deflection member 3, 4, 5 generates, in the extended position A, a separation D of the reverse air flow F-INV from the internal wall 21, making it possible to orient said reverse air flow F-INV in a substantially axial direction with an opposite sense to the upstream air flow F, originating the thrust reversal phase, while generating reduced weight and drag. In the retracted position B, the air intake 2 advantageously maintains its aerodynamic profile.