EP2591224A1

EP2591224A1 - Thrust reverser having an aerodynamic coupling for a front frame

Info

Publication number: EP2591224A1
Application number: EP11744046.1A
Authority: EP
Inventors: Guy Bernard Vauchel; Jean-Philippe Joret
Original assignee: Aircelle SA
Current assignee: Safran Nacelles SAS
Priority date: 2010-07-07
Filing date: 2011-06-17
Publication date: 2013-05-15
Also published as: CN102959223B; FR2962492A1; US20130126638A1; BR112013000033A2; CN102959223A; CA2802655A1; FR2962492B1; RU2013104292A; US8769926B2; WO2012004486A1

Abstract

The present invention relates to a thrust reverser (1) for a turbojet engine nacelle, including deflection means (2) combined with at least one movable cowl (5) mounted on at least one front frame (6) provided with means (8, 9) for connecting to a corresponding upstream portion (7), said movable cowl (5) being mounted so as to be movable between a closed position, in which it closes the nacelle and deactivates the deflection means, and an open position, in which it opens a passage and activates the deflection means, the thrust reverser being characterized in that the front frame has an upstream extension forming a deformable flap (111, 112) intended to aerodynamically interface with the upstream portion, and in that a portion of the movable cowl (15, 18) is shaped so as to interface, in the closed position, with said upstream attachment portion by forcing back the deformable flap.

Description

Thrust reversing device with aerodynamic junction

front frame

The present invention relates to a turbojet engine nacelle comprising a downstream section equipped with a thrust reverser device mounted on a front frame.

An aircraft is driven by several turbojet engines each housed in a nacelle also housing a set of ancillary actuating devices related to its operation and providing various functions when the turbojet engine is in operation or stopped, such as for example, a system of operation. thrust reversal.

A nacelle generally has a tubular structure comprising an air inlet upstream of the turbojet engine, a median section intended to surround a fan of the turbojet engine, a downstream section intended to surround the combustion chamber of the turbojet engine and housing, where appropriate, the means for thrust reversal, and is generally terminated by an ejection nozzle whose output is located downstream of the turbojet engine.

The modern nacelles are intended to house a turbofan engine capable of generating through the blades of the rotating fan a flow of hot air (also called primary flow) from the combustion chamber of the turbojet engine, and a flow of cold air (secondary flow) flowing outside the turbojet through an annular passage, also called vein, formed between a shroud of the turbojet engine and an inner wall of the nacelle. The two air flows are ejected from the turbojet engine from the rear of the nacelle.

The role of a thrust reverser is, during the landing of an aircraft, to improve the braking capacity thereof by redirecting forward at least a portion of the thrust generated by the turbojet engine. In this phase, the inverter obstructs the cold flow vein and directs the latter towards the front of the nacelle, thereby generating a counter-thrust which is added to the braking of the wheels of the aircraft.

The means implemented to achieve this reorientation of the cold flow vary according to the type of inverter. However, in all cases, the structure of an inverter comprises movable covers moved between, on the one hand, an extended position in which they open in the nacelle a passage for deviated flow, and secondly, a retracted position in which they close this passage. These covers can perform a deflection function (inverter with pivoting doors) or simply activation of other deflection means.

In the case of a grid inverter, also known as a cascade inverter, the reorientation of the air flow is carried out by deflection grids, the hood having a simple sliding function aimed at discover or cover these grids. Complementary locking doors, also called shutters, activated by the shedding of the cowling, generally allow a closing of the vein downstream of the grids so as to optimize the reorientation of the cold flow.

In order to support the mobile inversion hoods and to bind the downstream section to the remainder of the nacelle and in particular to the median section via the fan casing, the downstream section comprises fixed elements and in particular longitudinal beams connected upstream. to a substantially annular assembly called front frame, formed in one or more parts between said longitudinal beams, and intended to be fixed to the periphery of the downstream edge of the fan housing of the engine.

In the case of a reverser with gates with movable covers in translation, the fixed elements su pport com will typically take up two longitudinal beams said twelve hours, disposed on either side of a pylon of attachment of the nacelle or a pylon type interface, and two lower longitudinal beams said six hours.

These beams also serve as support for guiding rails in translation of the movable covers.

The front frame is then formed of two half-frames substantially hemicylindrical linking the upper and lower beams together on either side of a longitudinal axis of the nacelle.

In the case of a cascade type or gate type thrust reverser, this front frame also serves to support the set of deflection grids disposed between said beams.

In the thrust reversal position, the deflected air flows through the deflection grids from the flow passage between the front frame and an upstream edge of the retracted movable hood.

Thus, in order to maximize the thrust reversal performance, the front frame must have a streamlined aerodynamic profile. the flow of the deflected stream and the possibility of aerodynamic accidents in the flow path of the deflected air. This is why it has a curved profile, at least near the flow vein of the flow of air at its beginning of deflection. This curved portion is called the edge of deviation.

Some direct jet line accidents are not removable and must be minimized.

A first line accident exists due to the mounting of the front frame on the fan case. In addition to the difficulties of perfect alignment between the front frame and the casing at the interior of the vein, it should be noted that in order to avoid a scooping of the air by the front frame, an upstream edge of the interface between the front frame and the housing can be radiated outward.

In fact, it necessarily results in the presence of a cavity, constituting an aerodynamic accident in the vein.

In the same way, there is also necessarily a functional clearance between the front frame and the locking flaps which, in the closed position must come to better reconstitute the aerodynamic continuity of the inner vein. In order to avoid scooping, an upstream edge of the locking flaps is also curved towards the outside of the nacelle, thus creating a second cavity.

It should be noted, however, that the flaps are movable about a downstream pivot axis and that the flap mounting interface is not waterproof. There will therefore necessarily be minimal scooping through the housing cavities of the locking flaps.

Thus, in a non-inverted flow, said direct, the air flow meet at least two line accidents, respectively at an interface between the front frame and the fan casing, and at a flush between the frame front and shutters.

In the thrust reversal position, the deflected flow remains disturbed by the first cavity which, by disturbing the flow of the air flow, causes a slight delay in the deflection of the air flow which no longer perfectly adheres to the edge of the flow. deflection of the front frame.

It is therefore clear that both the direct jet and reverse jet performances can be impacted by these aerodynamic accidents. A first solution to simply respond to this problem is to raise a lower portion of the front frame to create a pocketing for receiving upstream locking flaps.

This solution is in particular described in document US Pat. No. 4,185,798.

A limitation of such a solution however lies in the fact that in reverse thrust mode, the air flow tends to continue its direct path and not to stick to the deflection edge, which significantly reduces the effectiveness of the thrust reversal device.

The object of the present invention is to provide an alternative solution that does not have such disadvantages and aims for this purpose with a thrust reverser device for a turbojet engine nacelle comprising, on the one hand, deflection means and, on the other hand, at least one cover movable relative to at least one fixed structure comprising at least one front frame at least partially peripheral and equipped with connecting means to a corresponding upstream part, said movable cover being movably mounted between a closed position in which it ensures the aerodynamic continuity of the nacelle and deactivates the deflection means, to an open position in which it opens a passage in the nacelle and activates the deflection means, the thrust reverser device being characterized in that the front frame has a deflection edge comprising an upstream extension forming a deformable flap intended to come into aerodynamic interface av ec the corresponding upstream part to which the front frame is attached, and in that a portion of the movable cowl is shaped so as ven ven, in the closed position, in interface with said upstream attachment part by forcing the deformable flap into withdrawal.

Thus, by providing a deformable interface flap, the latter may adopt a different configuration depending on the reverse thrust and pressure configurations in the turbojet engine.

In the direct jet position, that is to say in the closed position of the thrust reverser, a portion of the movable cowl is extended upstream so as to interface at the upstream portion of attachment. As a result, and similarly to US 4,185,798, there is only one interface area instead of two previously. The invention, thanks to the presence of the deformable flap, allows to reconstruct the current aerodynamic structure in reverse thrust mode. More specifically, in thrust reversal position, the deformable flap is no longer forced back and returns to the working position in which it ensures the aerodynamic continuity of the deflection edge with the upstream part of attachment.

Preferably, the upstream part of attachment of the front frame is a fan casing.

Preferably, the connecting means of the front frame to the upstream part of attachment are knife / throat type.

According to a preferred embodiment of the invention, the thrust reverser device is a thrust reverser with deflection grids, the movable cowl being movable in translation along a substantially longitudinal axis of the nacelle, covering and revealing the grids respectively in the closed and open position.

Preferably, the deflection grids are mounted on the front frame.

Advantageously, the portion of the movable cowl shaped so as to force the deformable bib is a locking flap, in particular pivotally mounted by an upstream end on the movable cowl.

Alternatively, it may be a dedicated upstream outgrowth of the movable cowl.

Advantageously, the deformable bib is sectorized. According to a first variant embodiment, the deformable flap is made from at least one elastomeric material. Preferably, the deformable flap comprises a lamella core, optionally covered with a flexible coating.

According to a second variant embodiment, the deformable flap is in the form of a pivoting flap mounted against an elastic return means towards its direct jet interface position.

Advantageously, the thrust reversal device comprises an abutment means limiting the return of the flap towards its direct jet interface position. This stop ensures optimal optimal positioning of the flap in its active configuration.

Advantageously, this stop may be adjustable, discrete, and located on the upstream part of attachment. The present invention will be understood in the light of the following detailed description with reference to the accompanying drawings in which:

FIG. 1 is a diagrammatic representation in longitudinal section of a thrust reverser device according to the prior art.

- Figure 2 is a partial schematic sectional representation of the device of Figure 1 equipped with a deformable flap according to a first embodiment.

- Figure 3 is a partial schematic sectional representation of the device of Figure 1 equipped with a deformable flap according to a second embodiment.

FIG. 4 is a schematic representation of an example of segmentation of the flap of FIG. 3.

FIGS. 5 and 6 are exemplary embodiments of the invention with a combination of a stop at the flush flange, the abutment being respectively located on a front frame and on the movable cover.

- Figure 7 is a schematic partial representation in which the thrust reverser device comprises a locking flap which interfaces with the flap.

FIG. 8 is a diagrammatic representation in longitudinal section of an embodiment variant in which the upstream interface structure is an outgrowth of the movable cover.

A thrust reversal device 1 with deflection grids 2 is shown schematically in longitudinal section in FIG. 1.

Such a thrust reverser device 1 equips a rear section of a nacelle surrounding a turbojet engine (not visible) and defines with a fixed internal fairing structure 3 of a rear part of the turbojet engine, a vein 4 for the circulation of a secondary air flow generated by the turbojet engine.

The thrust reverser device 1 comprises a movable cowl 5 mounted to be movable in translation along a substantially longitudinal axis of the nacelle between an open position in which the mobile cowl 5 is moved backwards, opens a passage in the nacelle and discovers the deflection grids 2, and a closed position in which it ensures the continuity of the nacelle and covers the deflection grids 2.

The movable cowl 5 is movable relative to a fixed structure, comprising, on the one hand, supporting and guiding beams (not visible), and on the other hand, a front frame 6, said front frame 6 possibly being made in several parts, and in particular in two semicylindrical half-parts.

The front frame 6 ensures the attachment of the thrust reverser device 1 to an upstream structure of the nacelle, in this case a casing 7 surrounding a blower of the turbojet engine via a link of the knife 8 / groove 9 type. at least partially peripheral.

The front frame 6 also supports the deflection grilles 2.

In order to ensure good guidance of the air flow in reverse thrust mode, the front frame 6 is equipped with a deflection edge 10 coming in continuity with the casing 7 and defining a curve towards the outside of the nacelle .

In accordance with the invention, the deflection edge 10 has an upstream extension forming a deformable flange intended to come into aerodynamic interface with the casing 7 to which the front frame 6 is attached.

In addition, a portion of the movable cover 5 is shaped so as to come, in the closed position, in interface with said upstream attachment part by forcing the deformable flap back.

Examples of embodiments are shown in Figures 2 to 8. Figure 2 shows a deformable flap made in the form of a flap 111 pivoted about a transverse axis A and forced in aerodynamic continuity position with the housing 7 by a spring 112. The flap can be made in the form of a plurality of sectorized peripheral flaps 111.

FIG. 3 shows a deformable flap made in the form of a tongue 121 made from an elastomer material and attached, in particular by gluing, in the upstream extension of the deflection edge 10. The tongue 121 can be made from a flexible lamella core and covered with a flexible coating allowing differences in positioning the lamellae between them. The bib can also be sectored.

The constitution of the flap can also be very simple and, as shown in Figure 4, this flap can be achieved by a lamellar arrangement 123 and have cutouts 124 which, in the retracted position come into contact or close, and provide a day in inversion position. Advantageously, and as shown in FIGS. 5 and 6, the tongue 1 21 flexible may be associated with a stop 25 retaining the interface position with the housing 7.

In FIG. 5, this abutment 1 25 is situated on a peripheral edge of the casing 7 and cooperates with a corresponding flange 126 of the tongue 121.

The same goes for FIG. 6 with the difference that the stop 125 is mounted on the front frame 6.

Of course, an abutment means can also be provided for the flaps made in the form of pivoting flaps 11 January 1 of Figure 2.

Advantageously complementary, the abutments 1 25 may be adjustable and discrete.

According to the invention, in the closed position, an upstream portion of the thrust reverser device 1 forcing the deformable flap into the retracted position and in its place providing the aerodynamic interface with the casing 7.

From the thrust reverser device 1 according to the prior art shown in FIG. 1, this upstream portion may be a locking flap 15 pivotally mounted by an upstream end on the movable cowl 5.

As can be seen in FIG. 7, this locking flap 15 will be slightly extended upstream to interface with the casing 7 in place of the deformable flap.

In order to improve the operation of the elements in contact and to ensure their longevity, a sliding ramp 16 may be applied, in particular on an inner end of the flap 15.

FIG. 8 shows a second embodiment in which the upstream part forcing the deformable flap in the retracted position and ensuring in its place the aerodynamic interface with the casing 7 is a fixed protrusion 1 8 of the movable cover 5 , the locking flap 17 remaining behind the upstream edge of the movable cowl 5.

This technology can likewise be applied for a gate inverter without shutter, the inversion being allowed by the internal lines of the S-shaped secondary channel and which is obstructed by the only recoil of the mobile structure (inverter also called " blockerless ").

Although the invention has been described with a particular embodiment, it is obvious that it is in no way limited and that it comprises all the technical equivalents of the means described, as well as their combinations if they fall within the scope of the invention.

Claims

1. Thrust reversing device (1) for a turbojet engine comprising, on the one hand, deflection means (2), and on the other hand, at least one movable cowl (5) relative to at least one fixed structure comprising at least one front frame (6) at least partially peripheral and equipped with connecting means (8, 9) to a corresponding upstream part (7), said movable cover being mounted movably between a closed position in which it ensures continuity aerodynamic of the nacelle and deactivates the deflection means, to an open position in which it opens a passage in the nacelle and activates the deflection means, the thrust reverser device being characterized in that the front frame has a deflection edge (10) comprising an upstream extension forming a deformable flap (January 1, 121) intended to ven on the aerodynamic interface with the corresponding upstream part to which the front frame is attached, and in that a part of the movable cowl (1 5, 1 8) is shaped so as to close in the closed position, interfacing with said upstream attachment part by forcing the deformable flap back.

2. Thrust reversing device (1) according to claim 1, characterized in that the upstream portion (7) of attachment of the front frame (6) is a fan casing.

3. thrust reversing device (1) according to any one of claims 1 or 2, characterized in that the connecting means of the front frame (6) to the upstream attachment part (7) are of knife type ( 8) / throat (9).

4. Thrust reversing device (1) according to any one of claims 1 to 3, characterized in that it is a thrust reverser with deflection grids (2), the movable cowl (5) ) being movable in translation along a substantially longitudinal axis of the nacelle, covering and uncovering the gates respectively in the closed position and opening.

5. Thrust reversing device (1) according to claim 4, characterized in that the deflection grids (2) are mounted on the front frame (6).

6. Thrust reversing device (1) according to any one of claims 1 to 5, characterized in that the portion of the movable cowl (5) shaped so as to force the deformable bib (1 1 1, 1 21 ) is a locking flap (15), in particular pivotally mounted by an upstream end on the movable cover.

7. thrust reverser device (1) according to any one of claims 1 to 6, characterized in that the deformable flap (1 1 1, 121) is sectorized.

8. thrust reverser device (1) according to any one of claims 1 to 7, characterized in that the deformable flap (121) is made from at least one elastomeric material.

9. thrust reverser device (1) according to claim 8, characterized in that the deformable flap (121) comprises a lamella core, optionally covered with a flexible coating.

1 0. thrust reverser device (1) according to any one of claims 1 to 7, characterized in that the flap (1 1 1) deformable is in the form of a pivoting flap mounted to meet an elastic return means (1 12) to its direct jet interface position.

1 1. Thrust reversing device (1) according to any one of claims 1 to 10, characterized in that it comprises a stop means (125) limiting the return of the flap (121) to its interface position in direct jet.