WO2009122026A1

WO2009122026A1 - Bypass turbojet engine nacelle

Info

Publication number: WO2009122026A1
Application number: PCT/FR2009/000229
Authority: WO
Inventors: Guy Bernard Vauchel
Original assignee: Aircelle
Priority date: 2008-04-02
Filing date: 2009-03-04
Publication date: 2009-10-08
Also published as: FR2929654B1; FR2929654A1

Abstract

The invention relates to a turbojet engine nacelle including a downstream section, fitted with a variable nozzle device, including a nozzle section (13, 113) moveably mounted along a substantially longitudinal axis of the nacelle relative to the latter inside a structure (12, 30) of the downstream section, the nozzle section being actuatable by at least one actuator (15, 115) including a rod (14, 117) extending through the structure of the downstream section wherein said nozzle section is mounted; and characterized in that the structure and the nozzle include at least one sealing means (20, 21, 40, 121, 123) disposed such that the inside of the nacelle is isolated from the outside of the nacelle across the assembly formed by the structure and the nozzle section.

Description

Twin-turbojet engine nacelle

The invention relates to a turbojet turbojet engine nacelle. An aircraft is driven by several turbojets each housed in a nacelle also housing a set of ancillary actuators related to its operation and providing various functions when the turbojet engine is in operation or stopped. These ancillary actuating devices comprise in particular a mechanical system for actuating thrust reversers. 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 housing a thrust reverser means and intended to surround the combustion chamber of the turbojet engine. , 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.

Although the invention is not limited to the case of nacelles equipped with an inverter but also applies to the case of said nacelles said smooth, the invention will be described below mainly in the case of a nacelle with inverter.

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. In addition to its thrust reversal function, the movable cowl belongs to the rear section and has a downstream side forming an ejection nozzle for channeling the ejection of the air flows. This nozzle can come in addition to a primary nozzle channeling the hot flow and is then called secondary nozzle.

The mobile cowl is thus equipped, as is known from document US Pat. No. 5,806,302, with at least one nozzle movable relative to said movable cowl, so as to adjust the ejection section of the annular channel as a function of the position of said nozzle. The mobile nozzle is also referred to as the movable structure for adjusting the nozzle section.

Each moving part, namely the reverse thrust cover on the one hand, and the movable nozzle on the other hand, is actuated by a dedicated actuator. This implies the presence of power supply circuits and control actuators extending inside the movable cowl, which is disabling from a maintenance and security point of view.

The French application FR 06/05512 also describes a variable nozzle system and discloses the use of a telescopic jack whose first rod is intended to actuate the movable cowl while the second rod is intended for adjusting the nozzle. Such a system makes it possible to respond to the problem of the centralization of the supply and control means at a front frame on which is fixed the base of the double action actuator.

Applications FR 07/04343, FR 07/06963 and FR 07/06964 also describe double-acting actuators for variable nozzle. One of the drawbacks of the use of double acting actuators with respect to separate actuators isolated for each movable element comes from the sealing of the inside of the nozzle and the inside of the movable cowl with respect to the outside of the nozzle. nacelle and the flow vein of the air flow. Indeed, in a double-acting actuator, the rod for actuating the variable nozzle also passes through the movable cowl. This can cause the presence of parasitic air flows that will impact the aeronautical performance of the whole.

When the thrust reverser is in the closed position, in particular, air flowing in the vein can escape through the space existing between the moving cowl and a front frame and then through the passage opening of the rod of the actuator to the nozzle before reaching the outside of the nacelle.

Thus, there is a need for a solution to properly isolate these different areas so as to limit air leakage through the body of the nacelle.

The invention aims to remedy this drawback and relates for this purpose to a turbojet engine nacelle comprising a downstream section equipped with a variable nozzle device, comprising a nozzle section mounted movably along a substantially longitudinal axis of the nacelle relative to the latter inside a structure of the downstream section, the nozzle section being adapted to be actuated by at least one actuator comprising a first rod passing through the structure of the downstream section inside which said section is mounted nozzle, characterized in that the structure and the nozzle comprise at least one sealing means arranged to isolate the interior of the nacelle from the outside of the nacelle through the assembly formed by the structure and the section of nozzle.

Thus, the presence of sealing means isolating the entire structure / nozzle greatly limits or even prevent any air leakage from inside the nacelle (high pressure) to the outside of the nacelle (low pressure) to through the downstream section of the latter. This generally improves aeronautical performance by improving the ejection of air flows through the nozzle section and thus the thrust generated by the propulsion unit.

Of course, it should be noted that the present invention may relate indifferently to a smooth nacelle, or a nacelle equipped with a thrust reverser device, the structure on which is mounted movable the nozzle section may be a fixed structure or a movable hood inverter.

Advantageously, the structure inside which the nozzle section is mounted is a movable thrust reverser cowl, said movable cowl being mounted in translation in a direction substantially parallel to a longitudinal axis of the nacelle adapted to pass alternately between a closing position in which it ensures the aerodynamic continuity of the nacelle and covers means of deflection, to an open position in which it opens a passage in the nacelle and discovers the deflection means, the assembly being adapted to be operated by at least one dual action actuator comprising a first rod connected to the movable hood and a second rod passing through the movable hood and connected to the movable nozzle.

By isolating, it is generally understood that the sealing means make it possible to greatly reduce, or even completely prevent, a circulation path between the outside and the inside of the nacelle through the assembly formed by the mobile cowl (the structure) and the nozzle. Indeed, the pressure prevailing outside the nacelle being lower than that prevailing inside, there would be air leakage through the hood / nozzle assembly, and loss of a part of the thrust flow, which reduces aeronautical performance.

Advantageously, the sealing means comprise a peripheral seal disposed between the base of the rod of the actuator connected to the nozzle section and an internal wall of the structure, upstream of a point of connection between the rod and said structure. . In the case of a double acting actuator, the base of the rod connected to the nozzle section is the first rod, linked to the movable cowl.

Alternatively, the sealing means comprise a peripheral seal disposed between the base of the rod of the actuator connected to the nozzle section and an internal wall of the structure, downstream of a point of connection between the rod and said structure. .

According to a first variant embodiment, the sealing means comprise a nozzle gasket disposed between a face of the nozzle oriented towards the inside of the nacelle and a wall of the structure.

According to a second embodiment, the sealing means comprise a nozzle gasket disposed between a face of the nozzle oriented towards the outside of the nacelle and a wall of the structure.

The present invention will be better understood from the description which follows with reference to the attached schematic drawing in which: Figure 1 is a schematic sectional view of a downstream section of a nacelle smooth according to the invention.

Figures 2 to 7 are schematic sectional views of several embodiments of the invention on a downstream section of a nacelle equipped with a thrust reversal device.

A nacelle is intended to constitute a tubular housing for a turbofan engine (not shown) with a large dilution ratio and serves to channel the air flows it generates through the blades of a blower (not shown), namely a hot air flow through a combustion chamber (not shown) of the turbojet, and a cold air flow flowing outside the turbojet (F).

A nacelle generally has a structure comprising a front section forming an air inlet, a central section surrounding the fan of the turbojet, and a downstream section surrounding the turbojet and may include a thrust reversal system.

The downstream section comprises an external structure optionally comprising a thrust reversal system and an internal structure

2 of the motor fairing defining with the outer surface a vein 3 for the circulation of a cold flow F in the case of a turbojet engine nacelle as discussed herein.

Figure 1 illustrates the case of a nacelle smooth, that is to say comprising a downstream section 1 comprising an outer section not equipped with a thrust reverser device.

This downstream section comprises a fixed part 11 having a front frame 11a on which is fixed a downstream structure 12 inside which is mounted a nozzle section 13 movable in translation along a substantially longitudinal axis of the nacelle.

This nozzle section 13 is driven in translation by a rod 14 of a jack 15 fixed in the fixed part and whose rod 14 passes through the downstream structure 12 through an orifice 18.

In the absence of leakage measurement, the nozzle section has an internal surface in communication with the vein 3 and an outer surface in communication with the outside of the nacelle. As a result, there may be a loss of airflow.

The air flow can also reach the inside of the fixed part 11 through the downstream structure 12. In order to overcome this problem, and according to the invention, the downstream section 1 comprises a first seal 20 disposed substantially at level of the front frame 11 around the cylinder 15 upstream of the rod 14 between said cylinder 15 and a wall of the fixed structure 12 upstream of the orifice 18.

This first seal 20 thus prevents any loss of air flow to the fixed portion 11 of the downstream section 1. The seal is also ensured by a second seal 21 disposed between an upper surface of the nozzle 13 and an inner wall of the downstream structure 12.

The second seal 21 thus prevents any leakage of the air flow to the outside of the nacelle and the interior of the downstream structure 12 is substantially at the outlet pressure of the vein 3.

FIG. 2 illustrates the case of a nacelle equipped with a thrust reverser device, that is to say one comprising a downstream section equipped with a cover 30 movable in translation along a substantially longitudinal axis of the nacelle between a closed position in which it ensures the aerodynamic continuity of an external structure 10 of the downstream section and covers means for deflecting the air flow F, and an open position in which it releases an opening in the structure external and activates deflection means (not visible) of the air flow F. The movable cowl 30 then replaces the downstream structure 12 and the nozzle section 13 is then mounted movably in translation inside said movable cowl 30.

The assembly is actuated by a double-acting cylinder 115, a base of which is fixed in the fixed part 11 and having, on the one hand, a first rod 116 able to actuate the movable cowl 30 and connected to the latter at a point of attachment. 31, and secondly, a second rod 117, passing through the movable cowl through an orifice 18 and connected to the nozzle section 13.

In the absence of leakage measurement, the nozzle section 13 has an internal surface in communication with the vein 3 and an outer surface in communication with the outside of the nacelle. As a result, there may be a loss of airflow.

The air flow can also reach an internal space 33 between the movable cover 30 and the fixed part 11 and escape through the interface between the movable cover 30 and said fixed part 11. Conversely, it is possible to lose a portion of the air flow from the thrust reversal system and then through the orifice 18 to the outside of the nacelle.

The interface between the movable hood 30 and the fixed part 11 is conventionally sealed with a seal 40 fixed below the actuator 115, either on the front frame 11a or on the movable hood 30 and adapted to come into contact with the movable hood 30 or the front frame 11a, respectively, so as to seal the interface when the movable cover is in the closed position.

The leaktightness of the other possible leak paths is ensured, on the one hand, by a first seal 120 disposed inside the movable cowl 30 near the orifice 18 around the first rod 116 of the jack 115 downstream of the fixing point 31 between a wall of the movable cover 30 and the first rod 116, and secondly, by a second seal 121 disposed between an upper surface of the nozzle 13 and an inner wall of the movable cowl 30.

Thus, the possible leakage of the air flow F is limited and the inside of the movable cowl 30 is substantially at the pressure at the outlet of the vein 3.

FIG. 3 illustrates a variant of the principle of FIG. 2, in which the second seal 121 is replaced by a seal 123 placed between a lower surface of a nozzle 113 and an inner wall of the movable cowl

Such an arrangement is more suitable for thicker nozzle sections 1 13 upstream, the thickness available between the upper surface of the nozzle 1 13 and the outside of the movable cowl 30 being then greatly reduced, which makes it difficult to accommodate an additional seal.

In such a case, the inside of the movable cowl 30 is situated substantially at the external pressure at the outlet of the vein 3. As shown in FIG. 4, this configuration is also adaptable to a fine nozzle 13 which may then have on its face lower a housing 13b adapted to receive the seal 123.

Another solution shown in FIG. 5 also consists in providing a shoulder 13c at an upstream end of the nozzle section 13, shoulder 13c under which the seal 123 may be housed.

Figure 6 shows a provision identical to the case of Figure 2 in which the seal 120 has been removed.

Indeed, it is possible to remove the seal 120 since the outside of the nacelle is isolated through the seals 40 and 121. The expace 33 and the inside of the movable cowl are both substantially at the pressure of the vein 3 and it is therefore not necessary to isolate the orifice 18 between them.

Figure 7 is a representation identical to Figure 2 but showing the nozzle section 13 in the deployed position. It goes without saying that the invention is not limited to the embodiments of this nacelle, described above as examples, but it embraces all variants. Thus, in particular, the mobile nozzle could be associated with a smooth nacelle and not with a nacelle equipped with a thrust reverser.

Claims

1. turbojet engine nacelle comprising a downstream section, equipped with a variable nozzle device, comprising a nozzle section (13, 113) mounted movable along a substantially longitudinal axis of the nacelle relative to the latter inside a structure (12, 30) of the downstream section, the nozzle section being adapted to be actuated by at least one actuator (15, 1 15) comprising a rod (14, 1 17) passing through the structure of the downstream section to the interior of which said nozzle section is mounted, characterized in that the structure and the nozzle comprise at least one sealing means (20, 21, 40, 121, 123) arranged so as to isolate the interior of the nacelle from the outside of the nacelle through the assembly formed by the structure and the nozzle section.

Nacelle according to claim 1, characterized in that the structure inside which the nozzle section (13, 113) is mounted is a movable thrust reverser cowl (30), said movable cowl being mounted in translation in a direction substantially parallel to a longitudinal axis of the nacelle adapted to pass alternately from a closed position in which it ensures the aerodynamic continuity of the nacelle and covers means of deflection, to an open position in which it opens a passage in the nacelle and discovers the deflection means, the assembly being able to be actuated by at least one double action actuator (1 15) comprising a first rod (1 16) connected to the movable hood and a second rod (1 17 ) passing through the movable hood and connected to the movable nozzle.

3. The nacelle according to any one of claims 1 or 2, characterized in that the sealing means comprise a peripheral seal (20, 120) disposed between the base of the rod (14, 117) of the actuator (15). , 115) connected to the nozzle section (13, 113) and an inner wall of the structure (12, 30), upstream of a connection point (31) between the rod and said structure.

4. Platform according to any one of claims 1 or 2, characterized in that the sealing means comprise a peripheral seal disposed between the base of the rod (14, 117) of the actuator (15, 115) connected to the nozzle section (13, 113) and an inner wall of the structure, downstream of a connection point between the rod and said structure.

5. Platform according to any one of claims 1 to 4, characterized in that the sealing means comprise a nozzle gasket (123) disposed between a face of the nozzle (13, 113) facing the inside of the nacelle and a wall of the structure (12, 30).

6. Platform according to any one of claims 1 to 4, characterized in that the sealing means comprise a nozzle gasket (31, 121) disposed between a face of the nozzle (13) facing outwardly of the nacelle and a wall of the structure (12, 30).