Thrust reverser comprising a deployable sealing membrane in a mixed flow vein

Abstract

The invention relates to a thrust reverser (30) for an aircraft propulsion system through which a primary flow, a secondary flow, and a mixed flow (20C) pass. The reverser comprises a fixed structure (31) equipped with at least one flow deflection device (32), and a movable structure (29) comprising at least one reverser cover (33) radially delimiting outwards a mixed flow channel (21C) of the propulsion system, arranged downstream of the secondary flow channel (21B) and intended to be traversed by the mixed flow (20C). According to the invention, the reverser is designed such that when the movable structure (29) is in the thrust reversal position, a deployed sealing membrane (58) is arranged at least partially within the mixed flow channel (21C). Figure for the abstract: Fig. 3

Description

Title of the invention: THRUST REVERSER COMPRISING A SHUT-OFF MEMBRANE DEPLOYABLE IN A MIXED FLOW VEIN Technical field

[0001] The invention relates to the field of nacelles and thrust reversers for aircraft propulsion systems, and, more particularly, to nacelles equipped with reversers with fixed flow deflection members, such as deflection grilles. State of the prior art

[0002] Thrust reversers are devices for diverting the airflow passing through the propulsion unit forward, so as to shorten landing distances and limit the stress on the brakes on the landing gear.

[0003] The grid reversers currently used in the aeronautical sector comprise deflection grids integrated into a fixed structure of the reverser, intended to be connected to a turbomachine casing. A movable structure of the reverser comprises one or more movable reverser cowls, and it is mounted so as to be movable in translation relative to the fixed structure between an advanced direct thrust position and a retracted thrust reverser position. In the advanced direct thrust position, the deflection grids are arranged in the housing of the reverser cowls, and they are isolated from the secondary flow path of the propulsion unit by a radially internal wall of the reverser cowls. On the other hand, in the retracted thrust reverser position, the retracted radially internal wall of the reverser cowls defines a passage opening towards the deflection grids.

[0004] Usually, to divert at least part of the secondary flow towards this passage opening in the direction of the grilles, the inverter is also equipped with shutters, which, when deployed, at least partially close the secondary vein. In a known manner, this forces the air of the secondary flow to pass through the passage opening and reach the grilles, which then generate the counter-thrust air flow towards the front.

[0005] The flaps are generally pivotally mounted on the radially internal wall of the inverter cowls, this wall delimiting the secondary vein radially outwards.

[0006] Thus, recesses are provided in this radially internal wall of the reverser cowls in order to receive the shutter flaps in the retracted position, as adopted in direct jet. However, in direct jet, the presence of the recesses and the flaps is a source of aerodynamic disturbances on the secondary flow. In addition, this locally limits the installation of an acoustic panel on the radially internal wall of the inverter covers.

[0007] To provide a technical solution to these problems, it has been proposed to replace the shutters with one or more membranes for closing the secondary vein. Such a design is known, for example, from document FR 3 076 864 A1.

[0008] However, the solutions proposed with sealing membranes remain perfectible, particularly with regard to the efficiency and performance of the inverter. Statement of the invention

[0009] The invention firstly relates to a thrust reverser for an aircraft propulsion unit traversed by a primary flow, a secondary flow, as well as a mixed flow, the reverser comprising a fixed structure equipped with a radially internal delimiting wall of a secondary vein of the propulsion unit intended to be traversed by the secondary flow, the reverser also comprising a movable structure comprising at least one reverser cowl delimiting radially outwards a mixed flow vein of the propulsion unit, arranged downstream of the secondary vein and intended to be traversed by the mixed flow, the reverser also comprising at least one flow deflection member, the movable structure being movable in translation relative to the fixed structure along a longitudinal central axis of the reverser, between an advanced direct thrust position and a retracted thrust reversal position,the thrust reverser also comprising at least one shut-off membrane designed to divert at least part of the gases from the propulsion unit towards the flow diversion member, when the mobile structure is in the retracted thrust reversal position.

[0010] According to the invention, the reverser is designed so that when the mobile structure is in the retracted thrust reversal position, the deployed shut-off membrane is arranged at least partly in the mixed flow vein.

[0011] Unlike the previously proposed embodiments in which the membrane closes the secondary flow, the invention now provides for closing the flow through which the mixed flow passes, namely the flow located downstream and resulting from the mixing of the primary and secondary flows. This possibility is offered by the ability of such membranes to withstand high temperatures, of the type encountered in the mixed flow. This results in greater efficiency and higher performance for the inverter, by acting on the mixed flow located downstream of the ejection of the primary and secondary flows, i.e. downstream of a flow mixer which is preferably provided on the propulsion unit.

[0012] In addition, the use of sealing membranes provides savings in terms of cost, mass, acoustic and aerodynamic performance. The invention is therefore the result of technological research aimed at significantly improving aircraft performance and, in this sense, contributes to reducing the environmental impact of these aircraft (decarbonization).

[0013] The invention preferably provides at least one of the following optional technical features, taken alone or in combination.

[0014] Preferably, the mobile reverser cowl has a housing open upstream and delimited between a radially external wall and a radially internal wall of this mobile reverser cowl, the flow deflection member being arranged, in the forward direct thrust position of the mobile structure, in the housing of the mobile reverser cowl while being isolated from the secondary flow stream and from the mixed flow stream by the radially internal wall of the mobile reverser cowl, and, in the retracted thrust reverser position of the mobile structure, the retracted radially internal wall of the mobile reverser cowl revealing upstream a passage opening towards the flow deflection member, the closure membrane being designed to deflect at least a portion of the mixed flow towards the passage opening and the flow deflection member, when the mobile structure is in the retracted thrust reverser position.

[0015] Preferably, the reverser also comprises at least one member for deploying the closure membrane, comprising a first end connected to the membrane, and a second end opposite the first end, said second end being connected to the mobile reverser cowl, or to the radially internal delimiting wall of the secondary vein, or to a flow mixer, or to a gas ejection cone. In the case of a connection to the mobile reverser cowl, in the direct thrust configuration, the deployment member such as a connecting rod generates little or no aerodynamic disturbances on the flow.In fact, the connecting rod is then preferably designed to be moved from a folded position, preferably upstream, adopted when the mobile structure occupies its forward direct thrust position, to a projecting position in the secondary vein, adopted when the mobile structure occupies its rearward thrust reversal position. This contributes even further to reducing the environmental impact of these aircraft.

[0016] Furthermore, by integrating the deployment member into the movable cover of the reverser in this way, the result is a reverser module which remains easy to mount within the propulsion unit, as well as to dismount. This results in savings in terms of time and costs.

[0017] Preferably, as mentioned above, the deployment member comprises a connecting rod and / or a cable, or a strap, or any other force transmission element of a flexible nature and of elongated shape.

[0018] In the invention, the flow deflection member may be an integral part of the fixed structure of the inverter, or of the mobile structure.

[0019] Preferably, the inverter comprises a device for actuating the deployment member, preferably comprising at least one spring for actuating this member. Thus, the actuating device is preferably of passive design, and it comprises elastic return means, preferably at least one compression spring. Alternatively, these could be controlled means, and activated only during the times when the stress is desired, for example during the opening and / or closing of the inverter, or only during certain phases of these operations on the inverter. As indicated above, a passive design is nevertheless preferred which also makes it possible to generate the desired forces in direct jet, in order to tension the membrane and reinforce its stability in the cavity in which it remains stored.

[0020] A hybrid design is also conceivable, in which elastic means would make it possible to generate the desired forces, but in combination with control means to adjust the stiffness of these elastic means according to the needs. For example, the stiffness could be adjusted during the opening of the reverser, so that the intensity of the forces generated remains sufficiently high to maintain the desired effect.

[0021] Preferably, in the thrust reversal configuration, the shut-off membrane extends over 360° around the longitudinal central axis of the reverser, at least partly in the mixed flow vein, and preferably entirely in this same vein.

[0022] The sealing membrane is therefore unique and continuous circumferentially over 360°, which limits edge effects, and advantageously allows self-balancing of this membrane. In addition, in the event of damage to one of the deployment members acting on this sealing membrane, the pressure forces applied to this membrane can be easily absorbed by the other deployment members associated with this membrane.

[0023] It is noted that the continuous nature of the sealing membrane, over 360° giving it a general annular shape, is also observed in its folded position, in direct thrust configuration.

[0024] Furthermore, it is also noted that such a 360° continuous sealing membrane could alternatively be used to divert the secondary flow into the secondary vein, in embodiments identical or similar to those presented for the present invention.

[0025] Preferably, in the forward position of direct thrust of the mobile structure, at least a portion of the sealing membrane is arranged radially between the deflection member and the radially internal wall of the mobile reverser cover, in the accommodation.

[0026] Preferably, still in the forward position of direct thrust of the mobile structure, the closure membrane bypasses downstream a rear frame supporting the flow deflection member, and it also has a part arranged radially between the deflection members and the radially external wall of the mobile cover, in the housing.

[0027] Alternatively, the end of the membrane could be fixed to the rear support frame of the flow deflection member, without departing from the scope of the invention.

[0028] Preferably, the sealing membrane is partly in abutment against an upstream end of the radially internal wall of the mobile reverser cowl or upstream and at a distance from this upstream end, when the mobile structure occupies its retracted thrust reverser position.

[0029] Preferably, when the mobile structure adopts its forward direct thrust position, the end of the sealing membrane is pinched between the upstream end of the radially internal wall of the mobile reverser cover, and a deflection edge belonging to the fixed structure of the reverser.

[0030] Preferably, one end of the sealing membrane is fixed to an upstream end of the radially external wall of the movable cover.

[0031] Alternatively, this end of the membrane could be fixed to the rear support frame of the flow deflection member, without departing from the scope of the invention.

[0032] Preferably, the sealing membrane is partly in abutment against an upstream end of the radially internal wall of the mobile reverser cowl or upstream and at a distance from this upstream end, when the mobile structure occupies its retracted thrust reverser position.

[0033] Preferably, when the mobile structure adopts its forward direct thrust position, the end of the sealing membrane is pinched between the upstream end of the radially internal wall of the mobile reverser cover, and a deflection edge belonging to the fixed structure of the reverser.

[0034] The invention also relates to a nacelle for an aircraft propulsion unit, comprising at least one fan cowl, as well as a thrust reverser as described above.

[0035] Finally, the invention also relates to a propulsion unit for an aircraft, comprising a turbomachine and such a nacelle.

[0036] Other advantages and characteristics of the invention will appear in the detailed non-limiting description below. Brief description of the drawings

[0037] The following detailed description refers to the accompanying drawings in which:

[0038] [Fig.l] is a schematic half-view in longitudinal section of a propulsion assembly, comprising a thrust reverser according to a preferred embodiment of the invention, and shown in direct thrust configuration;

[0039] [Fig.2] is a schematic half-view in longitudinal section of the reverser equipping the propulsion unit shown in [Fig.l], with the reverser in direct thrust configuration;

[0040] [Fig.3] is a schematic half-view of the reverser shown in [Fig.2], shown in the thrust reverser configuration;

[0041] [Fig.4] is a perspective view of the reverser shown in Figures 2 and 3, shown in a direct thrust configuration with a movable reverser cowl of “D” architecture;

[0042] [Fig.5] is a front view of the reverser similar to that of [Fig.4], with the reverser shown in the thrust reverser configuration, and having an “O” architecture;

[0043] [Fig.6] is a longitudinal sectional view of a reverser according to another preferred embodiment of the invention, the top half-section showing the reverser in the direct thrust configuration, and the bottom half-section showing the reverser in the reverse thrust configuration;

[0044] [Fig.7] is a longitudinal sectional view similar to that of the preceding figure, with the inverter being presented according to another preferred embodiment of the invention;

[0045] [Fig.8] is a longitudinal sectional view similar to that of the preceding figure, with the inverter being presented according to yet another preferred embodiment of the invention. Detailed description of embodiments

[0046] [Fig.l] shows an aircraft propulsion unit 1, having a longitudinal central axis A1.

[0047] Subsequently, the terms “upstream” and “downstream” are defined relative to a general direction SI of flow of the gases through the propulsion unit 1, along the axis A1 when the latter generates thrust. These terms “upstream” and “downstream” could respectively be substituted by the terms “front” and “rear”, with the same meaning.

[0048] The propulsion unit 1 comprises a turbomachine 2, a nacelle 3 as well as a mast (not shown), intended to connect the propulsion unit 1 to a wing (not shown) of the aircraft.

[0049] The turbomachine 2 is in this example a double-flow, double-spool turbojet comprising, from front to rear, a fan 5, a low-pressure compressor 6, a high-pressure compressor 7, a combustion chamber 8, a high pressure turbine 9 and a low pressure turbine 10. Compressors 6 and 7, combustion chamber 8 and turbines 9 and 10 form a gas generator. The turbojet 2 is provided with a fan casing 11 connected to the gas generator by structural arms 12.

[0050] The nacelle 3 comprises a front section forming an air inlet 13, a middle section which comprises two fan cowls 14 surrounding the fan casing 11, and a rear section 15.

[0051] In operation, an air flow 20 enters the propulsion unit 1 through the air inlet 13, passes through the fan 5 and then divides into a primary flow 20A and a secondary flow 20B. The primary flow 20A flows in a primary gas circulation vein 21A passing through the gas generator. The secondary flow 20B flows in a secondary vein 21B surrounding the gas generator. The secondary vein 21B is delimited radially inwards by a fixed internal fairing which envelops the gas generator. In this example, the fixed internal fairing comprises a first section 17 belonging to the middle section 14, and a second section 18 extending rearwardly from the first section 17, so as to form a part of the rear section 15. This second section 18 is an integral part of a fixed structure of a thrust reverser which will be described below.This same section will subsequently be called wall 18 of radially internal delimitation of secondary vein 21B.

[0052] Radially outwardly, the secondary vein 21B is delimited by the fan casing 11, and, in the configuration of [Fig.l], by one or more movable reverser cowls 33 forming a part of the rear section 15 of the nacelle 3, and which will be described later. More precisely, between the fan casing 11 and the movable reverser cowls 33, there is provided an outer shroud 40 of an intermediate casing 42, the latter comprising the aforementioned structural arms 12, the radially outer end of which is fixed to this shroud 40. The latter therefore also participates in delimiting the secondary vein 21B radially outwardly, by being located in the downstream axial extension of the fan casing 11.

[0053] It is noted that the radially internal delimiting wall 18 of the secondary vein 21B is extended downstream by a flow mixer 71, used to mix the primary and secondary flows 20A, 20B. The flow mixer 71 is of conventional design, of the type comprising external / internal lobes, corresponding to bumps and hollows, arranged alternately in the circumferential direction and visible in the figures. This mixer 71 is intended to promote the mixing of the primary and secondary flows. This gives rise, downstream of the mixer 71, to a mixed flow 20C in a vein 21C of mixed flow, delimited radially outwards by the movable cowl 33, partly by its internal wall 52, and radially inwards by a gas ejection cone 74. This is preferably the entirety of the radially internal surface of the movable cover 33 which delimits radially outwards the vein 21C, in addition possibly, with its upstream part, to delimiting radially outwards a portion of the secondary vein 21B.

[0054] The nacelle 3 therefore comprises a thrust reverser 30 centered on the axis A1 and comprising on the one hand a fixed structure 31 secured to the fan casing 11, and on the other hand a structure 29 movable relative to the fixed structure 31. The fixed structure 31 comprises for example a front frame 46 which connects it fixedly to the fan casing 11, preferably via a knife-edge flange assembly located downstream of the outer shroud 11. This front frame 46 contains a profiled aerodynamic part called a deflection edge 46B, which guides the flow in an inverted jet.

[0055] The fixed structure also comprises a plurality of deflection grids 32 arranged adjacent to each other around the axis A1, in a circumferential direction of the reverser 30 and the propulsion assembly 1. These grids 32 thus form flow deflection members to generate the counter-thrust. In this regard, it is noted that this flow reversal function can alternatively or simultaneously be carried out using a flexible structure, of the membrane / textile type.

[0056] Furthermore, the mobile structure 29 comprises the covers mobile reverser 33 mentioned above, for example two cowls 33 each extending over an angular amplitude of approximately 180°. This configuration with two cowls 33 is particularly well suited in the case of a nacelle design in which the cowls / walls 18 are also mounted articulated, so that the reverser 30 then has a so-called “D-shaped” architecture, known by the Anglo-Saxon name “D-Duct”. In this architecture, the cowls 18, 33 are connected so as to open / close simultaneously during maintenance operations on the engine. However, other architectures are possible, such as for example a so-called “C-shaped” architecture, known by the Anglo-Saxon name “C-Duct”, or even a so-called “O-shaped” architecture which is particularly preferred here, and known by the Anglo-Saxon name “O-Duct”. In this latter architecture, a single movable cover 33 is preferably provided, extending 360° around the axis AL

[0057] Each movable reverser cowl 33 comprises a radially external wall 50 forming an external nacelle aerodynamic surface, as well as a radially internal wall 52 participating in the delimitation of the secondary vein 21B radially outwards. This wall 52 is located in the downstream continuity of the deflection edge 46B. The two walls 50, 52 define a housing 54 open axially at the upstream end of the movable reverser cowl 33.

[0058] [Fig.l] shows the reverser 30 in a forward thrust configuration, called “direct jet”, corresponding to a standard flight configuration. In this configuration, the cowls 33 of the mobile structure 29 are in a closed position, called advanced thrust or “direct jet” position, in which these reverser cowls 33 bear on the fixed structure 31, in particular on the deflection edge 46B forming an integral part of the latter. Indeed, in the direct thrust configuration, the upstream end 52a of the radially internal wall 52 of each cowl 33 bears axially against the deflection edge 46B.

[0059] The mobile structure 29 is thus movable in translation relative to the fixed structure 31 along the axis A1 of the reverser, between the forward direct thrust position shown in [Fig.l], and a retracted thrust reversal position which will be described later. In the forward direct thrust position of the mobile structure 29, the deflection grids 32 are arranged in the housing 54 of the reverser cowls 33, being isolated from the secondary vein 21B and from the mixed flow vein 21C by the radially internal wall 52 of these sliding reverser cowls 29. This wall 52, forming the external wall of the secondary vein and also of at least a portion of the mixed flow vein, is also called an acoustic internal panel.

[0060] This direct thrust configuration is also shown in Figures 2 and 4, while the retracted thrust reversal position of the mobile structure 29 is shown in Figures 3 and 5. In [Fig. 3], it is shown that the retracted internal acoustic panel 52 of the reverser cowls reveals upstream a passage opening 56 towards the deflection grilles 32. This opening 56 is located either in the secondary flow path 21B, or in the mixed flow flow path 21C, or in a part of each of these two flow paths.

[0061] The opening 56 is also delimited upstream by the deflection edge 46B, which flares radially outwards going towards the rear, to delimit an air flow intended to pass through the grilles 32 when the mobile system is in this rearward thrust reversal position. In other words, the deflection edge 46B gradually moves away from the axis A1 going from the front to the rear, to guide / deflect the air towards the grilles 32 in the thrust reversal configuration.

[0062] In order to divert at least a portion of the mixed flow 20C toward the passage opening 56 defined axially between the diversion edge 46B and the upstream end 52a of the radially inner wall 52 of each cover 33, the inverter 30 comprises one or more shut-off membranes 58. Subsequently, an embodiment will be described in which a single membrane 58 is associated with each mobile inverter cover 33 while having an identical or similar angular amplitude, but it remains conceivable to provide several circumferentially adjacent membranes associated with each cover 33. Similarly, only the cooperation between a membrane 58 and its associated cover 33 will be described below, it being understood that this cooperation is identical or similar for each cover of the inverter 33.

[0063] The membrane 58 can be made of a material known to those skilled in the art. for this type of application. For example, it may be a non-impregnated fabric, for example aramid fibers. The membrane 58 may also be made using a composite material whose matrix is ​​particularly flexible, for example aliphatic polyurethane, which allows use in different temperature conditions, in particular lower temperatures in the case of an aliphatic polyurethane membrane than in the case of a silicone membrane. For example, Kevlar fabrics provide excellent resistance to high temperatures for the membranes, and are therefore particularly well suited to cooperate with the mixed flow 20C, in the corresponding vein 21C. For example, such membranes can withstand temperatures of up to 300°C, or even 500°C.

[0064] The matrix provides a low bending recovery capacity and the behavior of the structure obtained is indeed that of a membrane. One of the major properties of this membrane 58 is that it can bend in a perfectly reversible manner (elastic or by fiber sliding) with a very small radius of curvature relative to its surface, and to have a very small thickness, for example of the order of 0.1 to 3 mm. For information purposes, it is observed that this membrane 58 behaves like a boat sail or a parachute / a flying wing when it is put under pressure.

[0065] Below, the attachment of the membrane 58 to the inverter 30 will be described. Still with reference to FIGS. 1 to 5, attachment means are provided connecting a first end 58a of the closing membrane 58 to an upstream end 50a of the radially external wall 50 of the movable cover 33. Alternatively, the first end of the membrane 58a is fixed to a rear frame 60 for supporting the grids 32, this annular support or support in the form of an annular section in fact connecting the rear end of several adjacent grids.

[0066] In addition, a second end 58b of the sealing membrane 58, opposite the first membrane end 58a, is connected to the movable cover 33 using deployment members 62, which will be described later and which here preferably correspond to connecting rods.

[0067] Furthermore, as is best seen in [Fig. 2], when the mobile structure 29 occupies its forward direct thrust position, a portion of the closure membrane 58 is arranged radially between the deflection grids 32 and the radially inner wall 52 of the mobile reverser cowl 33, in the housing 54. In addition, the closure membrane 58 bypasses the rear support frame 60 downstream, and it also has another portion arranged radially between these deflection members 32 and the radially outer wall 50 of the mobile cowl 33, still in the housing 54.

[0068] Preferably, the two parts of the membrane 58 which are located in this housing 54 of the mobile inverter cover 33, each radially cover the entire length of the grids 32. The membrane 58 is thus housed in the housing 54 by being folded radially on either side of the grids 32, with a fold defined at the level of the contact zone with the downstream end of the rear grid support frame 60.

[0069] When the mobile structure 29 adopts its forward direct thrust position, the second end 58b of the membrane 58 is pinched between the upstream end of the internal wall 52 of the mobile cover, and the deflection edge 46B. In order to avoid possible damage to the membrane 58 due to this pinching, the deflection edge 46B may locally have a notch of a shape adapted to receive the upstream end 52a of the wall 52. Thus, the membrane 58 is also pressed into this notch of the deflection edge 46B, by the support of the upstream end of the wall 52.

[0070] Also, as can be seen in [Fig. 3], when the mobile structure 29 moves and occupies its rearward thrust reversal position at the end of this movement, the closing membrane 58 is partly in abutment against the upstream end 52a of the radially internal wall 52 of the mobile reverser cowl, thus corresponding to the acoustic panel. More precisely, during the rearward movement of the mobile structure 29, the membrane 58 slides on this upstream end 52a of the radially internal wall 52.

[0071] Thus, the part of the membrane 58 which is located radially outwards relative to its bearing zone on the wall 52 closes the upstream axial opening of the housing 54, while the other part located radially inwards closes at least part of the secondary vein 2IB or of the mixed flow vein 21C, thereby diverting at least part of the gases from the propulsion unit towards the passage opening 56, in the direction of the grids 32.

[0072] One of the particularities of this embodiment lies in the fact that the second membrane end 58b is no longer connected to the wall 18 (also called IFS, from the English “Inner Fixed Structure”), but it is connected to the movable cover 33.

[0073] To do this, several deployment rods 62 are provided here, circumferentially spaced from each other. Each rod 62 comprises a first rod end 62a connected to the second membrane end 58b, as well as a second rod end 62b opposite the first, and connected to the movable reverser cover 33.

[0074] Preferably, this second connecting rod end 62b is connected in an articulated manner to the movable cover 33, via a ball joint 64 arranged on the internal wall 52, or downstream of the latter, as shown in [Fig. 2]. In the forward direct thrust position, the second connecting rod end 62b is located downstream of the first connecting rod end 62a, with this connecting rod 62 arranged in the upstream folded position, and of axial or substantially axial orientation. When the mobile structure 29 occupies its retracted thrust reversal position, the connecting rod 62 then adopts a projecting position in the mixed flow vein 21C, after having pivoted radially inwards around the connection 64. In this position, the first connecting rod end 62a is located for example downstream of the flow mixer 71, but still upstream of the second connecting rod end 62b, for example by bearing against the gas ejection cone 74 of the propulsion unit.

[0075] Consequently, one of the particularities of the invention lies in the fact that the deployed sealing membrane 58 is arranged at least partly in the vein 21C, and preferably entirely in the latter, in order to be able to seal at least partly the mixed flow 20C formed downstream of the mixer 71. It is thus this mixed flow 20C which is at least partly sealed, then directed towards the grids 32 in order to generate the desired counter-thrust.

[0076] When the movable cowl 33 is opened, corresponding to its movement towards the rear, the part of the membrane 58 located close to its second end 58b is exposed to the secondary flow 20B and / or to the mixed flow 20C, which causes the deployment of the membrane 58 in the corresponding vein(s), as well as that of the connecting rod. To ensure this good deployment, the reverser can be equipped with an actuating device 70 associated with one or more of the connecting rods 62. The device 70 is preferably installed on the movable cowl 33, comprising for example a compression spring acting on the connecting rod 62, in order to force it towards its projecting position in the vein 21C. It is noted that the actuating device 70 and the articulated connection 64 could be produced within the same assembly, without departing from the scope of the invention.

[0077] Thanks to this actuating device 70, the connecting rod 62 forces the membrane 58 to deploy correctly during the initial phase of opening the reverser, and thus avoids the risks of this membrane being pressed against the wall 52 of the movable cowl 33. Furthermore, in the direct thrust configuration, the elastic means of this device 70, which act on the folded connecting rod 62, make it possible to keep the membrane in tension when it is stored in the cowl cavity 54. This contributes to its stability, and facilitates its deployment during a subsequent operation of opening the reverser.

[0078] When the reverser is closed, the connecting rod 62 folds back automatically, due to the force exerted by the membrane 58 on the first end of the connecting rod 62a. This force is itself generated by the support of the moving membrane, on the rear support frame 60, on either side of which this membrane 58 folds back. The folding back of the connecting rod 62 also leads to the reloading of the elastic return means of the actuating device 70. It is noted that this actuating device 70, or any another similar device, could be configured to also participate in folding the connecting rod 62 during the closing stroke of the movable hood 33, without departing from the scope of the invention.

[0079] It is also specified that in the direct thrust configuration, the deployment rod 62 can be held in the folded position by a controlled mechanism, configured to release this rod as soon as the reverser opens.

[0080] In order to limit the aerodynamic impact of the connecting rod 62 on the secondary flow and / or on the mixed flow in the direct thrust configuration, this connecting rod can be buried or partially buried in the movable cowl 33. To do this, in the advanced direct thrust position of the movable structure, the connecting rod 62 is housed at least in part, and preferably in its entirety, in a recess 72 provided on the radially internal wall 52 of the cowl 33.

[0081] This recess 72, which is open radially inwards to allow the connecting rod 62 to penetrate into this recess, and to extract itself therefrom during the opening of the reverser, here extends downstream beyond the housing 54, as is best seen in [Fig. 3]. The recess 72, in the form of an imprint of the connecting rod 62, can thus be produced locally in the acoustic panel, without damaging the primary function of this panel.

[0082] In [Fig. 5] showing the membrane 58 in the deployed position in the mixed flow vein, this sealing membrane has an angular extent of 360°, that is to say that it remains uninterrupted in the circumferential direction, around the axis A1 around which this membrane is preferentially centered. As indicated previously, this membrane could alternatively be segmented into several membranes succeeding one another in the circumferential direction, without departing from the scope of the invention.

[0083] In the case of a single membrane 58 continuous over 360°, at least its radially internal portion is located in the mixed flow vein 21C, downstream of the mixer. But it is preferably the entirety of this single, annular membrane 58 which is located in the vein 21C.

[0084] Another preferred embodiment of the invention is shown in [Fig.6]. Here, the second end of the connecting rod 62b is articulated via the connection 64 on the fixed part 31 of the reverser, preferably on the outer shell 40 which delimits the secondary vein 21B, radially outwards. The tilting of the connecting rod 62 is thus carried out downstream and radially inwards.

[0085] Another preferred embodiment of the invention is shown in [Fig.7], showing a deployment member corresponding to a connecting rod, a cable, or the combination of the two. The first end 62a remains connected to the second membrane end 58b, while the second end 62b is connected to the wall 18, or on the mixer which extends it downstream.

[0086] Finally, another preferred embodiment is shown in [Fig. 8], showing the deployment members 62 in the form of cables, a first end 62a of which is connected to the second membrane end 58b, and a second end 62b of which is connected to the actuating device 70, in the form of a cable tensioning device. This device 70 is here preferentially installed on the gas ejection cone, in the vein 21C.

[0087] Various modifications may be made by those skilled in the art to the invention which has just been described, solely by way of non-limiting examples, and the scope of which is defined by the appended claims. For example, the thrust reverser 30 may alternatively have a “D”, “C” or “O” architecture. In addition, all the features disclosed above, in the various preferred embodiments and their alternatives, are combinable with each other. Moreover, it is noted that in all the figures which have been described above, the elements which bear the same numerical references correspond to identical or similar elements.

[0088] It is noted that if the preferred embodiments which have been described above provide a flow deflection member 32 integrated into the fixed structure 31 of the inverter, it could alternatively be part of the mobile structure 29, for example by being fixed to the front of the mobile inverter cover 33.

Claims

Claims

1. Thrust reverser (30) for an aircraft propulsion unit traversed by a primary flow, a secondary flow, and a mixed flow, the reverser comprising a fixed structure (31) equipped with a radially internal delimiting wall (18) of a secondary vein (21B) of the propulsion unit intended to be traversed by the secondary flow (20B), the reverser also comprising a movable structure (29) comprising at least one reverser cowl (33) radially outwardly delimiting a vein (21C) of mixed flow of the propulsion unit, arranged downstream of the secondary vein (21B) and intended to be traversed by the mixed flow (20C), the reverser comprising at least one flow deflection member (32), the movable structure being movable in translation relative to the fixed structure along a longitudinal central axis (A1) of the reverser, between an advanced direct thrust position and a retracted position reverse thrust,the thrust reverser also comprising at least one shut-off membrane (58) designed to divert at least part of the gases from the propulsion unit towards the flow diverting member (32), when the mobile structure (29) is in the retracted thrust reversal position, characterized in that the reverser is designed so that when the mobile structure (29) is in the retracted thrust reversal position, the deployed shut-off membrane (58) is arranged at least partly in the mixed flow stream (21C).,

2. A reverser according to claim 1, characterized in that the mobile reverser cowl (33) has a housing (54) open upstream and delimited between a radially external wall (50) and a radially internal wall (52) of this mobile reverser cowl (33), the flow deflection member (32) being arranged, in the forward direct thrust position of the mobile structure, in the housing (54) of the mobile reverser cowl, being isolated from the secondary flow stream and the mixed flow stream by the radially internal wall (52) of the mobile reverser cowl (33), and, in the retracted thrust reversal position of the mobile structure (29), the retracted radially internal wall (52) of the mobile reverser cowl revealing upstream a passage opening (56) towards the deflection member (32), the closing membrane (58) being designed to deflect at least part of the flow mixed (20C) towards the passage opening (56) and the deflecting member (32), when the mobile structure (29) is in the rearward thrust reversal position.

3. Inverter according to claim 1 or 2, characterized in that the inverter also comprises at least one member (62) for deploying the closure membrane, comprising a first end (62a) connected to the membrane, and a second end (62b) opposite the first end, said second end (62b) being connected to the movable inverter cover (33), or to the radially internal delimiting wall (18) of the secondary vein (21B), or to a flow mixer (71), or to a gas ejection cone (74).

4. Inverter according to the preceding claim, characterized in that the flow deflection member (32) is part of the fixed structure (31) of the inverter, or of the mobile structure (29).

5. Inverter according to any one of the preceding claims, characterized in that it comprises a device (70) for actuating the deployment member (62), preferably comprising at least one spring for actuating this member.

6. Reversal according to any one of the preceding claims, characterized in that in the thrust reversal configuration, the closure membrane (58) extends over 360° around the longitudinal central axis (Al) of the reversal, at least partly in the mixed flow vein (21C), and preferably entirely in this same vein (21C).

7. Inverter according to any one of the preceding claims combined with claim 2, characterized in that in the advanced position of direct thrust of the mobile structure (29), at least a part of the closing membrane (58) is arranged radially between the deflection member (32) and the radially internal wall (52) of the mobile inverter cover (33), in the housing (54).

8. Inverter according to claim 7, characterized in that in the advanced position of direct thrust of the mobile structure (29), the closure membrane (58) bypasses downstream a rear frame (60) supporting the flow deflection member (32), and it also has a part arranged radially between the deflection members (32) and the radially external wall (50) of the mobile cover (33), in the housing (54).

9. Nacelle (3) for an aircraft propulsion unit, comprising at least one fan cowl (14), as well as a thrust reverser (30) according to any one of the preceding claims.

10. Propulsion assembly (1) for aircraft, comprising a turbomachine (2) and a nacelle (3) according to the preceding claim.