Thrust reverser including an improved deflection edge.

Abstract

Device and Method: Thrust reverser (20) for a propulsion system (10), comprising a fixed part (29), a movable part (39), and an actuation device (38), adapted to move the movable part (39) between the closed and deployed states, the fixed part comprising a deflection edge (40) adapted to direct an airflow from the inside of the thrust reverser outwards through a counter-thrust opening, characterized in that said deflection edge (40) has a surface (50) configured to generate turbulence in the fluid flow along the deflection edge (40) and minimize fluid separation along said deflection edge (40). Figure for the abstract: Fig. 8.

Description

Title of the invention: Thrust reverser comprising an improved deflection edge. technical field

[0001] The present exposition relates to the field of thrust reversers, in particular for the nacelles of a propulsion assembly. Previous technique

[0002] Thrust reversers are elements of a turbomachine nacelle that allow a portion of the airflow passing through the turbomachine to be directed forward, in order to reverse the thrust exerted by the turbomachine and slow down the aircraft on which the turbomachine is mounted in the event of landing or emergency braking, for example during an aborted takeoff.

[0003] In particular, among the known thrust reversers are grid thrust reversers and gate thrust reversers.

[0004] The grid thrust reversers include grids extending over a circumference of the propulsion system and having forward-directed aerodynamic profiles, as well as actuators driving the grids and a movable hood.

[0005] Under normal conditions, that is, when the propulsion system generates thrust, for example during flight, the movable cowling is in a closed state in which it covers the grilles, thus preventing air from escaping the propulsion system through them. The air escapes through a nozzle located downstream of the reverser. However, when the reverser is deployed to generate counter-thrust, the movable cowling slides along the propulsion system and flaps pivot to prevent air from exiting through the nozzle. The reverser is then in a deployed state in which it uncovers the grilles, allowing the airflow to pass through them and be redirected forward.

[0006] Thrust reversers with doors have doors forming portions of the nacelle, and movable between a closed position in which they conform to the geometry of the nacelle to allow airflow through the nacelle, and an open position in which they are tilted so as to close all or part of the passage of air through the nacelle, and to deflect the airflow radially outwards through transverse counter-thrust openings opened by the deployment of the doors, in order to push the airflow forwards and thus generate a counter-thrust. Description of the invention

[0007] The present invention thus aims to address at least partially these problems matics.

[0008] To this end, the present invention relates to a thrust reverser for a propulsion system, comprising a fixed part, adapted to be mounted on a propulsion system so as to encircle the latter, a movable part sealed against the fixed part by blocking a counter-thrust opening in the closed state, while the counter-thrust opening is released in the deployed state, and an actuation device adapted to move the movable part between the closed and deployed states, the fixed part comprising a deflection edge adapted to direct an airflow from the inside of the thrust reverser outwards through the counter-thrust opening, characterized in that said deflection edge has a surface configured to generate turbulence in the fluid flow along the deflection edge and minimize fluid separation along said deflection edge.

[0009] By propulsion system, we mean a turbomachine, such as a turbojet, or an electric or hybrid propulsion device.

[0010] According to one example, said deflection edge surface has concave recesses formed in said deflection edge surface.

[0011] According to one example, said recesses are concave alveoli having a surface in the form of a portion of a sphere.

[0012] According to one example, said recesses are grooves formed in the surface of the deflection edge, said grooves extending parallel or perpendicular to a direction of airflow over the deflection edge.

[0013] According to one example, said surface of the deflection edge has a portion having locally increased roughness.

[0014] According to one example, said deflection edge surface has vortex generators.

[0015] According to one example, said deflection edge surface has convex portions forming protuberances on said deflection edge surface.

[0016] According to one example, said convex portions have the shapes of a portion of a sphere.

[0017] The present description also relates to a nacelle comprising a thrust reverser according to one of the preceding claims.

[0018] The present disclosure further relates to a propulsion assembly for an aircraft, comprising a nacelle as defined above and a propulsion system, in particular a turbomachine such as a turbojet, or an electric or hybrid propulsion device, and also an aircraft comprising such a propulsion assembly. Brief description of the drawings

[0019] The invention and its advantages will be better understood upon reading the detailed description below of various embodiments of the invention given by way of non-limiting examples.

[0020] [Fig-1] The [Fig.1] is a side view of an example aircraft.

[0021] [Fig.2] Fig.2 represents a side view of an example of an inverter assembly push, in which the gondola is not shown.

[0022] [Fig.3] Fig.3 represents a side view of another example of a thrust reverser assembly, in which the nacelle is not shown.

[0023] [Fig.4] Fig.4 represents a side view of another example of a thrust reverser assembly, in which the nacelle is not shown.

[0024] [Fig.5] The [Fig.5] is a cross-sectional view along an axial plane representing a first example of this thrust reversing assembly.

[0025] [Fig.5] The [Fig.5] is a cross-sectional view along an axial plane representing a second example of this thrust reversing assembly.

[0026] [Fig.6] Fig.6 presents a cross-sectional view of another embodiment of a thrust reverser.

[0027] [Fig.7] The [Fig.7] schematically illustrates the separation of the airflow.

[0028] [Fig.8] Fig.8 schematically illustrates one effect of the invention.

[0029] [Fig.9] The [Fig.9] is a perspective representation of an embodiment.

[0030] [Fig. 10] The [Fig. 10] schematically represents another embodiment.

[0031] [Fig. 11] The [Fig. 11] schematically represents another embodiment.

[0032] [Fig. 12] The [Fig. 12] schematically represents another embodiment.

[0033] [Fig. 13] The [Fig. 13] schematically represents another example of an embodiment.

[0034] [Fig. 14] The [Fig. 14] schematically represents another example of an embodiment.

[0035] [Fig. 15] The [Fig. 15] schematically represents another example of an embodiment.

[0036] Throughout all the figures, the common elements are identified by identical numerical references. Description of the implementation methods

[0037] In the present description, the terms "axial", "radial", "tangential", "Circumferential," "internal," "external," and their derivatives are defined with respect to the main axis of the turbomachine; the "axial plane" is understood to be a plane passing through the main axis of the turbomachine, and the "radial plane" is understood to be a plane perpendicular to this main axis; the terms "upstream," "downstream," "front," and "rear" are defined with respect to the airflow within the turbomachine; angular positions are considered in a cylindrical coordinate system with the main axis of the turbomachine as its axis, with angles being measured positively in the counterclockwise direction as viewed from the side downstream of the turbomachine; finally, the terms "height" and "width" are defined in the local axial plane along the axial and radial directions, respectively; and unless otherwise stated, two elements shall be considered "close" or "near" (respectively "distant" or "distant") if their angular positions are close (respectively "distant") in the cylindrical frame, preferably less than 30°, preferably even less than 10°.

[0038] Fig. 1 is a schematic side view of an example aircraft 1, comprising a fuselage 2 from which a wing 4 extends laterally by means of wing roots 3. Aircraft 1 has an empennage at the rear, comprising a fin 5 on which a horizontal plane 6 is fixed. A propulsion system 10, in particular a turbomachine such as a turbojet, or an electric or hybrid propulsion device, is mounted on each side of the fuselage 2, at the rear thereof, by means of a jet engine mast.

[0039] Aircraft example 1 in [Fig. 1] is for illustrative purposes only, and any other arrangement of the structural elements is possible according to the general knowledge of a person skilled in the art. In particular, the propulsion systems 10 are not limited to two, and may be arranged under the wing 4 rather than at the rear of the fuselage 2.

[0040] Figures 2, 3, and 4 show various examples of a propulsion system 10 having a principal axis A represented by a dashed line. The airflow (or air stream) in the propulsion system 10 is shown in the diagrams from left to right. The inlet of the propulsion system 10 has a blower 11 that draws air into the propulsion system 10. The air stream is then divided into a primary air stream I and a secondary air stream IL. The primary air stream I is compressed successively by a low-pressure compressor and a high-pressure compressor, driven respectively by a low-pressure turbine and a high-pressure turbine. Between the compressors and the turbines is a combustion chamber that receives the air compressed by the compressors and into which the fuel is injected to initiate combustion.The combustion gases exit the combustion chamber, driving the turbines, and join the secondary airflow II at the outlet. The latter flows through the propulsion system 10 on the radial periphery of the primary airflow I. A mixer is typically positioned at the turbine outlet to promote the mixing of the two gas flows I and II and thus optimize the total thrust of the gases exiting through the nozzle 18, at the distal end of the propulsion system 10.

[0041] A rear part of the propulsion system 10 has a thrust reverser assembly 20, located on a circumference of the propulsion system 10. Figures 2, 3 and 4 show different thrust reverser structures which are described below.

[0042] In the example illustrated in [Fig. 2], a side view of a propulsion system 10 with a thrust reverser assembly 20 is shown. The thrust reverser 20 The system comprises a fixed part 29, including the fixed components in the engine's frame of reference, and a movable part 39, translating relative to the fixed part 29. The fixed part 29 includes at least one reversing grille 23, extending over a circumferential contour of the propulsion system 10 and positioned within a counter-thrust opening in the fixed part 29. The movable part 39 is movable between a closed and an open state. In the closed state, the movable part closes the counter-thrust opening and thus also closes the reversing grille 23, so that the airflow passes through the nacelle. In the open state, the movable part 39 closes all or part of the secondary airflow II in the nacelle, and directs it towards the counter-thrust opening and therefore towards the reversing grids 23, the latter being formed in such a way as to direct the airflow upstream and thus generate a thrust reversal.Such a thrust reverser 20 is commonly referred to as a grid reverser. Figure 5 is a detailed cross-sectional view along an axial plane representing an example of such a grid thrust reverser 20, in which the moving part 39 is actuated by a drive device 33 so as to at least partially obstruct the passage of air through the propulsion system, thereby redirecting all or part of the airflow to the grids 23 to perform the thrust reversal function.

[0043] Fig. 3 represents a side view of another example of a thrust reverser assembly 20 which is commonly referred to as a gated thrust reverser.

[0044] The thrust reverser 20 as presented comprises a fixed part 29, including the fixed parts in the engine's frame of reference, and a movable part 39. In such a thrust reverser, the movable part 39 defines one or more pivoting gates relative to the fixed part 29, typically 2 or 4 gates, typically rotatable in the plane perpendicular to the engine axis. The gates 39 can pivot under the action of the actuator 33 between a closed configuration in which the gates 39 are extensions of the fixed part 29, and an open configuration as shown in [Fig. 6], in which the air passage within the nacelle is at least partially obstructed, so that the airflow symbolized by an arrow is at least partially redirected by the gates 39 towards a radial opening that has been uncovered by the pivoting of the gates 39.In the case of a gated reversing valve, this radial opening is typically not equipped with a grid. The orientation of the gates 39 and, where applicable, their geometry will allow all or part of the flow to be redirected upstream, and to generate a thrust reversal.

[0045] A ferrule 25, at the rear of the thrust reverser 20, is fixed and coaxial with the fixed part 29 upstream of the reverser. [Fig. 6] shows a detailed cross-sectional view of such an example of a thrust reverser with gates.

[0046] Figure 4 shows a side view of another example of a thrust reverser assembly 20, which is usually referred to as a thrust reverser. Target type.

[0047] The thrust reverser 20 comprises a fixed part 29, including the fixed parts in the engine's frame of reference, and a movable part 39. This movable part 39 comprises one or more movable elements that rotate in the plane perpendicular to the engine axis and that at least partially obstruct the airflow passing through the nacelle in order to redirect it, as in the case of a thrust reverser with gates as described with reference to [Fig. 3]. Unlike the example described in [Fig. 3], the thrust reverser 20 shown in [Fig. 4] does not include a ferrule downstream of the thrust reverser 20. The counter-thrust opening is defined here between the movable elements and the fixed part 29.

[0048] It is understood that one problem is to direct the airflow towards the counter-thrust opening or towards the grids depending on the type of thrust reverser.

[0049] For this purpose, the fixed part 29 of the thrust reverser 20 has a deflection edge 40. This deflection edge forms the portion of the fixed part 29 immediately upstream of the counter-thrust opening or the grids.

[0050] The airflow along this deflection edge depends on several characteristics.

[0051] A phenomenon of airflow separation from the deflection edge is observed, resulting from a known phenomenon of airflow boundary layer separation as schematically illustrated in [Fig. 7], which depicts the airflow boundary layer separation for a thrust reverser 20 with a grid, it being understood that this phenomenon is also observed for a thrust reverser with a gate. In this figure, the airflow is represented by an arrow F. It can be seen in this figure that the airflow gradually moves away from the surface of the deflection edge 40 due to air recirculation symbolized by the arrow Rc.

[0052] Indeed, given the operating conditions of a propulsion system, and in particular the airflow velocity, such a separation phenomenon tends to occur when the geometry of the deflection edge is not suitable. The laminar flow along the deflection edge 40 causes the air to move at a speed too high to follow the profile of the deflection edge 40, resulting in boundary layer separation. A low-pressure recirculation zone is thus formed between the separated boundary layer and the deflection edge 40, this recirculation zone being, in effect, non-functional.

[0053] Boundary layer separation will reduce the airflow through the grids 23 or the thrust reverser opening 20 due to low pressure recirculation zones, thus reducing the airflow through the thrust reverser 20, and therefore decreasing the performance of the thrust reverser 20.

[0054] A conventional solution is to modify the dimensions of the edge of The deviation 40 is increased in length, that is, its dimension along the axial direction, so that the evolution of the deviation edge 40 is more gradual and less abrupt. However, such an increase in the length of the deviation edge 40 increases the mass and size of the assembly, which is detrimental to a propulsion system.

[0055] The present invention thus proposes a solution to minimize the separation of the airflow while minimizing the size and mass of the deflection edge 40 and therefore more generally of the thrust reverser 20.

[0056] Figure 8 schematically illustrates one effect of the invention.

[0057] This figure shows a modified deflection edge 40 according to the invention, having a surface configured to generate turbulence in the fluid flow along the deflection edge.

[0058] Such a surface structure of the deflection edge 40 will disrupt the fluid flow, thereby preventing the boundary layer from separating from the deflection edge 40. The fluid flow will thus follow the contour of the deflection edge 40, which will reduce or eliminate boundary layer separation. Consequently, the adhesion of the airflow to the deflection edge 40 will increase, maximizing the airflow through the grids 23 or the thrust reverser opening 20, and thus maximizing the effect of the thrust reverser 20.

[0059] The invention as proposed thus aims to modify the surface of the deflection edge 40 by introducing irregularities 50 in order to generate turbulence in the flow, and thus to optimize the airflow through the thrust reverser 20 by avoiding or reducing the separation of the airflow.

[0060] In the example shown schematically in [Fig.8], the deflection edge 40 is provided with cavities or concavities arranged in the surface of the deflection edge which define such irregularities 50 which form vortices which disturb the flow of fluid on the surface of the deflection edge 40 and which thus prevent the flow from separating.

[0061] Fig. 9 is a perspective representation of such an embodiment, in which the irregularities 50 are concave pits or recesses formed on the surface of the deflection edge 40. These pits or recesses typically have the shapes of a portion of a sphere, and are, for example, regularly distributed over all or part of the surface of the deflection edge 40.

[0062] Fig. 10 schematically represents another embodiment, in which the surface of the deflection edge 40 has irregularities 50 which are convex alveoli, forming protrusions from the surface of the deflection edge 40. These protrusions typically have the shapes of a portion of a sphere, and are, for example, regularly distributed over all or part of the surface of the deflection edge 40.

[0063] Figure 11 schematically represents another embodiment, in which the surface of the deflection edge 40 has an irregularity 50 formed by a concave groove in the deflection edge 40. The groove typically extends radially with respect to an axis of rotation of the turbomachine or nacelle under consideration, i.e., perpendicularly to the direction of flow of the flux F. The groove is shown here with a rectangular cross-section. It is understood that one or more grooves may be formed, extending radially or otherwise, with a rectangular or other cross-section.

[0064] Figure 12 schematically represents another embodiment, in which the surface of the deflection edge 40 has irregularities 50 formed by several concave grooves formed in the deflection edge 40. In the illustrated example, the concave grooves have a rectangular cross-section and are formed so as to extend in the direction of the flow F. It is understood that the number and shape of the grooves thus formed can vary.

[0065] Figure 13 schematically represents another embodiment, in which the irregularities 50 are formed by a plurality of cracks on the surface of the deflection edge 40. In the illustrated example, a plurality of parallel cracks are formed, extending perpendicularly to the direction of flow of the flux F from the external surface of the deflection edge 40. As an example, several cracks can be formed next to each other, each having a width between 1 mm and 10 mm.

[0066] Fig. 14 schematically represents another example of an embodiment in which the surface of the deviation edge 40 is modified so as to define a portion having increased roughness which thus define irregularities 50.

[0067] By increased roughness, we mean here that the surface condition of a portion is locally degraded, that is to say, that a portion of the surface of the deflection edge 40 has a surface condition that is degraded relative to the surface condition of the rest of the deflection edge 40, for example, a higher roughness. By way of example, the portion in question may have a roughness coefficient Ra between 10 pm and 200 pm, or between 50 pm and 200 pm.

[0068] Fig. 15 schematically represents another example of an embodiment in which the surface of the deflection edge 40 includes irregularities 50 which are formed by vortex generators.

[0069] The vortex generators as presented are formed by thin blades protruding from the surface of the deflection edge 40. They are typically installed in pairs, each of the vortex generators being inclined with respect to the direction of fluid flow so as to define a V-shaped configuration.

[0070] These different embodiments thus present different alternatives for to disrupt the airflow at the deflection edge 40, and thus generate turbulence such as vortices to prevent, minimize or reduce the boundary layer separation effect along the deflection edge 40, and thus maximize the airflow through the grids or the thrust reverser opening 20, i.e. the airflow contributing to thrust reversal, without requiring an increase in the volume of the deflection edge 40. More generally, the invention aims to create one or more irregularities so as to generate a low pressure area via a non-smooth or irregular surface of the deflection edge 40, this low pressure area thus disrupting the airflow to avoid or reduce the separation phenomenon.

[0071] Such a modification of the deflection edge 40 finds a particular application in the context of a nacelle, or more precisely of a propulsion assembly which may in particular equip an aircraft.

[0072] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than a restrictive sense.

Claims

Demands

1. Thrust reverser (20) for a propulsion system (10), having a main axis (A), comprising a fixed part (29), adapted to be mounted on a propulsion system (10) so as to encircle the latter, a movable part (39) attached in a sealed manner against the fixed part (29) by blocking a counter-thrust opening in the closed state, while the counter-thrust opening is released in the deployed state, and an actuation device (38), adapted to move the movable part (39) between the closed state and the deployed state, the fixed part comprising a deflection edge (40) adapted to direct an airflow from the inside of the thrust reverser to the outside through the counter-thrust opening,wherein said deflection edge (40) has a surface (50) configured to generate turbulence in the fluid flow along the deflection edge (40) and minimize fluid separation along said deflection edge (40), characterized in that said surface of the deflection edge (40) has concave recesses formed in said surface of the deflection edge (40).

2. Thrust reverser (20) according to claim 1, wherein said recesses are concave cavities having a surface in part of a sphere.

3. Thrust reverser (20) according to claim 1, wherein said recesses are grooves formed in the surface of the deflection edge (40), said grooves extending parallel or perpendicular to a direction of airflow over the deflection edge (40).

4. Nacelle comprising a thrust reverser (20) according to any one of the preceding claims.

5. Propulsion assembly for an aircraft, comprising a nacelle according to claim 4 and a propulsion system.

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