Patent ID: 12234790

It should be noted that the figures set out the invention in detail in order to implement the invention, said figures may of course be used to better define the invention where applicable.

DETAILED DESCRIPTION

Aircraft Propulsion Unit

As shown inFIG.2Aand described previously, the aircraft propulsion unit8extends along a longitudinal axis X oriented from upstream to downstream and comprises a turbine engine7and a nacelle3. The turbine engine7extends along the longitudinal axis X and is configured to allow propulsion of the aircraft from the acceleration of an inner air flow F-INT circulating from upstream to downstream in the turbine engine7. The nacelle3extends outwardly around the turbine engine7along the longitudinal axis X and makes it possible to guide the inner air flow F-INT in the turbine engine7. Subsequently, the terms “upstream” and “downstream” are defined with respect to the orientation of the longitudinal axis X. The terms “inner” and “outer” in turn are defined along the radial direction with respect to the longitudinal axis X.

Still as shown inFIG.2Aand as described previously, the turbine engine7is of the bypass type and comprises upstream a fan4rotatably mounted about the longitudinal axis X to accelerate the inner air flow F-INT from upstream to downstream. The turbine engine7also comprises, downstream of the fan4, a radially inner primary duct5and a radially outer bypass duct6, which are configured to guide respectively a first portion of the inner air flow F-INT, known as the primary air flow F1, for fuel combustion, and a second portion of the inner air flow F-INT, known as the bypass air flow F2, in order to generate the thrust of the turbine engine7.

Still in reference toFIG.2Aand as described previously, the nacelle3extends radially outwards to the fan4and radially outwardly delimits the bypass duct6. At its upstream end, the nacelle3comprises an air inlet1delimiting an annular cavity13of longitudinal axis X. The air inlet1comprises an inner wall10turned towards the longitudinal axis X and an outer wall11opposite the inner wall10, connected together upstream by an air inlet lip12comprising a leading edge. The air inlet1makes it possible to separate an upstream air flow F into the inner air flow F-INT guided by the inner wall10and an outer air flow F-EXT guided by the outer wall11.

Thrust Phase A and Thrust Reversal Phase B

As shown inFIG.2Band described previously, to reduce the braking distance of an aircraft, especially during landing, the aircraft propulsion unit8further comprises thrust reversal means in order to modify the orientation of the air flow in the bypass duct6. In what follows, a thrust phase A (FIG.2A) is distinguished wherein the bypass air flow F2circulates from upstream to downstream in the bypass duct6and a thrust reversal phase B (FIG.2B) wherein a reverse air flow F-INV circulates from downstream. It is specified that during a thrust reversal phase B, an inner air flow of F-INT from the upstream air flow F circulates from upstream to downstream at the root of the fan4to supply the primary air flow F1as well as in thrust phase A. The primary air flow F1may also be supplied by a portion of the reverse air flow F-INV.

In the example inFIG.2B, the thrust reversal means are formed by the fan4, which is of the variable-pitch type, abbreviated as “VPF”. Such a variable-pitch fan4comprises blades the pitch angle of which is controlled (seeFIG.2B) so as to reverse the direction of air flow in the bypass duct6. In practice, during a thrust reversal phase B, the reverse air flow F-INV circulates from downstream to upstream in the bypass duct6and then passes through the fan4and is guided upstream by the inner wall10of the air inlet1. The reverse air flow F-INV then opposes the upstream air flow F, which allows braking.

It goes without saying that the thrust reversal means could be in a form other than that described in this example. For example, it is known by patent application FR2120172A1 to at least partially obstruct the bypass duct6, downstream of the fan4, and to jointly uncover the grids not shown housed in the nacelle3in order to form the reverse air flow F-INV oriented inversely to the bypass air flow F2. However, such a thrust reversal system has a larger mass and size than the variable-pitch fan4.

Air Inlet with Variable Geometry

In reference toFIGS.2A and2B, according to the invention, the air inlet1is of the variable geometry type, i.e. it comprises a profile adapted for a thrust phase A and another profile adapted for a thrust reversal phase B. More precisely, according to the invention, the air inlet1comprises openings14formed in the inner wall10and mobile members2. A mobile member2is mounted pivoting in each opening14. Each mobile member2comprises a covering wall20and a deflecting wall21opposite the covering wall20and is configured to pivot between:a covering position P1(FIG.2A), wherein the covering wall20is turned towards the longitudinal axis X, obstructs the opening14and extends in the extension of the inner wall10of the air inlet1so as to guide the bypass air flow F2in order to promote a thrust phase A, anda deflecting position P2(FIG.2B), wherein the deflecting wall21is turned towards the longitudinal axis X, obstructs the opening14and is configured to separate the reverse air flow F-INV in order to promote a thrust reversal phase B.

As shown inFIG.2B, the mobile members2in the deflecting position P2advantageously make it possible to form a deflected reverse air flow F-INVDat the air inlet1, which is separated from the inner wall10contrary to the prior art. Such a deflected reverse air flow F-INVDopposes the upstream air flow F, which improves the thrust reversal B, unlike the undesirable bonded reverse air flow F-INVCof the prior art (seeFIG.1B).

Openings

In the example ofFIGS.3A and3B, the air inlet1comprises twenty openings14-1,14-2,14-3. The openings14-1,14-2,14-3are aligned transversely to the longitudinal axis X. Thus, a same transverse plane passes through each opening14-1,14-2,14-3. The openings14-1,14-2,14-3are further spaced from each other, and in this example equidistributed around the circumference of the inner wall10. Thus, the inner wall10comprises fixed blades18each extending between two consecutive openings14. The fixed blades18extend longitudinally with respect to the longitudinal axis X and connect the inner wall10extending respectively upstream and downstream of the openings14.

Still in the example ofFIGS.3A and3B, a single mobile member2is mounted in each of the openings14, so that the air inlet1comprises the same number of mobile members2as openings14. Similarly to the openings14, the mobile members2are mounted aligned in a plane transverse to the longitudinal axis X, are spaced from each other and, in this example, equidistributed along the circumference of the inner wall10. Such an air inlet1advantageously allows global and homogeneous separating of the reverse air flow F-INV during a thrust reversal phase B. The mobile members2are furthermore easily pivotable without contact or mutual interference.

It is specified that the number of openings14, equal to twenty in this example, is any in the framework of the invention. Preferably, the number of openings14is greater than ten for sufficient separating and less than forty to limit complexity. Moreover, it goes without saying that the openings14can be positioned differently on the inner wall10. As examples, the openings14could be arranged in a staggered pattern instead of being aligned. The openings14could also be closer to each other on an angled portion of the inner wall10to locally reinforce the separating. The openings14could in particular be adjacent, namely communicating with each other and forming together a global opening, over all or an angular portion of the inner wall10for a continuous separating. It should be noted that no fixed blade18extends between adjacent openings14and that the associated mobile members2are mounted adjacent in the same global opening.

Preferably, as shown inFIGS.3A and3B, the openings14are identical to each other, i.e. of the same shape and size. This makes it possible to use identical mobile members2with standardized shape and size, allowing large-scale production. The size of the openings14is determined by the diameter of the inner wall10of the air inlet1and the number of openings14. With regard to their shape, each opening14comprises an upstream end15and a downstream end16(seeFIG.3A) so as to cooperate with the mobile member2, as will be seen later. In the example ofFIGS.3A and3B, the upstream end15and the downstream end16each extend in a plane transverse to the longitudinal axis X. The upstream end15and the downstream end16are connected by curved side ends19(seeFIG.3A) so that the opening14comprises a variable circumferential width along the longitudinal axis X, minimal at the upstream end15and at the downstream end16and maximal between the latter. Such a shape makes it possible to promote cooperation with the mobile member2as well as obstruction of the opening14by the mobile member2, as will be seen later. It goes without saying that the openings14may comprise a different shape, such as a constant circumferential width along the longitudinal axis X.

Mobile Members

A mobile member2is described in what follows, then its cooperation with opening14, this description being valid for each mobile member2.

In reference toFIG.4, the mobile member2comprises a through-opening28extending along a pivot axis X2, so as to be able to be mounted pivotally around a pivot extending along said pivot axis X2. The mobile member2also comprises a covering wall20and a deflecting wall21, opposite the covering wall20, which extend on either side of the through-opening28longitudinally in relation to the pivot axis X2. The covering wall20comprises a convex shape that reproduces the profile of the inner wall10of the air inlet1. The deflecting wall21comprises a concave shape to deflect the reverse air flow F-INV.

As shown inFIG.4, the mobile member2also comprises a separating end22and a blocking end23connecting on either side the covering wall20and the deflecting wall21and extending longitudinally with respect to the pivot axis X2. In addition, the mobile member2comprises side walls27extending transversely with respect to the longitudinal axis X and passed through by the through-opening28. The side walls27connect the covering wall20, the deflecting wall21, the separating end22and the blocking end23.

In reference toFIG.4, the deflecting end22has a pointed shape, preferably at an angle α of less than 30°, so as to effectively separate the reverse air flow F-INV. The blocking end23is configured to cooperate with the upstream end15and the downstream end16of the opening14. In this example, the blocking end23comprises a first groove24, formed on the side of the covering wall20and configured to cooperate in shape complementarity with the upstream end15of the opening14, as well as a second groove25, formed on the side of the deflecting wall21and configured to cooperate in shape complementarity with the downstream end16of the opening14. It goes without saying that the blocking end23could cooperate differently with the upstream end15and/or the downstream end16of the opening14. Still in this example, the side walls27preferably comprise a shape identical to the side ends19of the opening14. This allows the mobile member2to obstruct the opening14in the covering position P1as in the deflecting position P2.

As shown inFIG.4, the mobile member2extends on either side of the through-opening28. Preferably, the through-opening28is substantially central, i.e. it is as close to the deflecting end22as to the blocking end23. The term “substantially” here means that a deviation of 10% is tolerated. This advantageously allows a passive switchover as will be presented later.

Preferably, the mobile member2is monoblock, i.e. made of the same material, to ensure its robustness and durability. Preferably, the mobile member2comprises a composite material with good mechanical strength. Still preferably, the mobile member2is obtained by machining or by3D printing.

Covering Position P1and Deflecting Position P2

In reference toFIG.5AandFIG.5B, the mobile member2is mounted mobile in the opening14around a pivot26tangential to the inner wall10and belonging to a plane transverse to the longitudinal axis X. This advantageously makes it possible to use the force of the inner air flow F-INT and the reverse air flow F-INV, circulating longitudinally, to facilitate the movement of the mobile member2. In this example, the pivot26is off-centered upstream in the opening14to promote a switchover during the thrust reversal phase B as will be seen later. According to one aspect, as shown inFIG.6A to6C, the pivot26is connected to an active control member29, such as an actuator, to move the mobile member2, whether or not complementary to the force of the air flow. Thus, the position of the mobile member2can be conveniently controlled to achieve a separating.

As shown inFIGS.5A and5B, the blocking end23of the mobile member2is further away from the pivot26than the upstream15and downstream16ends of the opening14in order to limit the rotation of the mobile member2between the covering position P1and the deflecting position P2. This makes it possible to hold the blocking end23inside the annular cavity13and the deflecting end22outside the annular cavity13in the inner air flow F-INT. In other words, the rotation of the mobile member2is limited to half a turn by the contact of the blocking end23on the inner wall10.

Preferably, the pivot26is common to several mobile members2, and preferably comprises an annular shape of longitudinal axis X to be common to all the mobile members2, in order to move them simultaneously. Such a pivot26makes it possible to facilitate the grouped control of a plurality of mobile members2.

As shown inFIG.5A, in the covering position P1, the covering wall20is turned towards the longitudinal axis X and obstructs the opening14in the extension of the inner wall10, in order to preserve the aerodynamics of the air inlet1in the thrust phase A. The blocking end23extends in radial bearing inwards on an inner face10intof the inner wall10. More precisely, the first groove24of the blocking end23cooperates by complementarity of shapes with the upstream end15of the opening14. This allows the mobile member2to be held in the covering position P1. The deflecting end22extends along an outer face10extof the inner wall10. The deflecting end22more precisely ensures continuity between the covering wall20and the downstream end16of the opening14. As shown inFIG.5C, in the covering position P1, the air inlet1has a divergent inner section for the inner air flow F-INT circulating from upstream to downstream as well as a smooth profile avoiding separation of the flow lines.

As shown inFIG.5B, in the deflecting position P2, the deflecting wall21is turned towards the longitudinal axis X and the separating end22extends protruding upstream and inward with respect to the opening14, thanks to the off-centered assembly of the pivot26. The concave shape of the deflecting wall21and the pointed shape of the separating end22effectively separate the reverse air flow F-INV from the inner wall10, while preserving the aerodynamics. In addition, the deflecting wall21obstructs the opening14in the deflecting position P2, which prevents the circulation of air in the air inlet1. This helps to ensure aerodynamics and does not disrupt de-icing. The locking end23, on the other hand, extends in radial bearing inwards on an inner face10intof the inner wall10. More precisely, the second groove25of the blocking end23cooperates by complementarity of shapes with the upstream end16of the opening14, and more precisely with an edge17of the upstream end16which extends protruding upstream. The blocking end23advantageously ensures alone that the deflecting position P2is held so that the separating end22does not bear on the inner wall10. This promotes its durability. As shown inFIG.5D, in deflecting position P2, the air inlet1has a convergent inner section for the reverse air flow F-INV, advantageously forming a nozzle convergent.

The separating end22, which is thin, is not solicited to hold the mobile member2in position. The blocking end23, thicker, makes it possible to hold the mobile member2in position.

To summarize, the variable geometry air inlet1of the invention comprises mobile members2mounted pivoting in openings14so that, either the covering wall20(covering position P1) or the deflecting wall21(deflection position P2), obstructs the opening14. The performance in thrust reversal phase B is advantageously improved, as the reverse air flow F-INVD, instead of hugging the contour of the air inlet1, is deflected to oppose the entire upstream air flow F, which promotes braking. In addition, this avoids forming an unwanted bonded reverse air flow loop F-INVCas in the prior art (seeFIG.1B). The aerodynamics are preserves in thrust phase A.

Method for Using

In reference toFIGS.6A,6B, and6C, a method for using the air inlet1previously described is described below. The turbine engine7is initially considered in thrust phase A and the mobile members2in the covering position P1(seeFIG.2A). During a thrust reversal phase B, the pitch angle of the blades of the fan4is modified, which generates a reverse air flow F-INV in the bypass duct6(seeFIG.2B). As shown successively inFIG.6AtoFIG.6C, the active control member29moves during a movement E1each mobile member2to the deflecting position P2by a simple pivoting of a half turn. The movement is advantageously promoted by the force exerted by the reverse air flow F-INV flowing from downstream to upstream on the separating end22extending internally. The blocking end23, on the other hand, extends outwards, into the annular cavity13of the air inlet1, protected from the reverse air flow F-INV.

Subsequently, during a new thrust phase A, the pitch angle of the blades of the fan4is modified again, which generates an inner air flow F-INT in the bypass duct6(seeFIG.2A) and stops the reverse air flow F-INV. As shown successively inFIG.6CtoFIG.6A, the active control member29moves during a movement E2each mobile member2into the covering position P1by a simple reverse pivoting of a half-turn. The movement is advantageously promoted by the force exerted by the inner air flow F-INT circulating from upstream to downstream on the separating end22extending internally. The blocking end23, on the other hand, extends outwards, into the annular cavity13of the air inlet1, protected from the inner air flow F-INT.

The movements E1, E2of the mobile members2between the covering position P1and the deflecting position P2are advantageously fast, easy and reproducible as desired.

In the example ofFIGS.6A,6B, and6C, the movement E1or E2is controlled by the active control member29. Alternatively, as shown inFIGS.7A and7B, at least a portion of the motion E1or E2could be passively implemented by the inner air flow F-INT and the reverse air flow F-INV. In the example ofFIGS.7A and7B, the movements E1, E2are entirely passively implemented.

To do this, as shown inFIG.7A, in the covering position P1, a reduced space is formed between the downstream end16of the opening14and the separating end22of the mobile member2so that the reverse air flow F-INV can engulf there and create a lever effect to initiate the movement E1of the mobile member2to the deflecting position P2. Once the movement E1is initiated, the action of the reverse air flow F-INV on the deflecting wall21makes it possible to obtain the deflecting position P2. Preferably, the separating end22extends radially inwards with respect to the downstream end16, so as to facilitate the passage of air between the separating end22and the downstream end16and the initiation of the movement E1.

In reference toFIG.7B, the movement E2from the deflecting position E2to the covering position E1is ensured by the action of the inner air flow F-INT on the separating end22at the upstream end15of the opening14as well as on the covering wall20. Advantageously, in the deflecting position P2, the separating end22protrudes inwards and upstream, which allows the inner air flow F-INT to exert a lever effect and initiate the movement E2.