FR2971765A1 - Pylon for fixing open-rotor pusher or pusher unducted fan engine in aircraft, has bored zone provided at upper face and/or lower face and comprising openings to allow passage of blown air from internal empty space toward outside of pylon - Google Patents

Abstract

The pylon (401) has a trailing edge (403) extended by an upper face and a lower face of the pylon. An internal empty space is formed between the upper face and the lower face to receive blown air. A bored zone (402) is provided at the upper face and/or the lower face, and comprises a set of openings (407) to allow the passage of the blown air from the internal empty space toward the outside of the pylon. A mobile grid comprises a set of openings that are positioned against the openings of the bored zone when the pylon is in open state.

Description

Fastening pylon with blow function for an aircraft engine with propellant propellers

TECHNICAL FIELD OF THE INVENTION The present invention relates to a fastening pylon with a blowing function for an aircraft engine, and in particular for an aircraft engine with unpaved propeller propellers (in English "open-rotor pusher" or " pusher unducted fan "). The field of the invention is that of fastening structures between aircraft and engines. Such structures are present in particular in engines of the propellant propeller propeller type, which comprise two contrarotating turbines each of which is integral in rotation with at least one propeller located outside the nacelle of the engine, the two propellers being arranged coaxially one behind the other at the downstream end of the engine. The propulsion system is thus hooked to the fuselage of the aircraft by means that transmit to the aircraft the forces generated by the engine during its various operating modes. The attachment means of the propulsion system generally comprise a very robust and very heavy piece called pylon which is arranged between the narrowing of the aircraft and the engine nacelle. The pylon extends substantially in a plane passing through the longitudinal axis of the engine, and comprises means of suspension of the engine through which pass all the forces transmitted between the engine and the aircraft. Such a configuration is shown diagrammatically in FIG. 1, which shows, in plan view, a pylon 101 connecting a motor 102, or propulsion system, of an aircraft, said engine 102 being of the non-propulsive propeller type. not careened, and the narrowing 103 (corresponding to the rear portion) of said aircraft. As illustrated, the motor 102 includes a first propeller 104 and a second propeller 105, propelling the aircraft in a direction 106. In another variant,

also concerned by the invention, a single helix is present; we then talk about turboprop engines in rear fuselage hanger. TECHNOLOGICAL BACKGROUND OF THE INVENTION The use of aircraft engines with propeller propellers not carinated necessarily leads to the appearance of a wake in the airflow meeting the pylon 101, said trail being generated by the pylon 101 ensuring the structural junction between the airplane and the propulsion system, a wake that impacts the blades of the propellers 104 and 105. This phenomenon is illustrated schematically in FIG. 2, on which is represented a sectional view of the pylon 101 in its conventional configuration, or conventional, and a sectional view of the propeller 104; in this figure, the speed of the air flow is represented by arrows 201, the length of which is representative of the value of the speed at the point considered. It is of course found that the speeds of the points situated at the height of the pylon 101 are less important than the speeds observed at the points where the airflow is not impacted by the presence of said pylon. These differences in speed give rise to a wake 202, constituted by all the points for which the speed of the air flow is affected by the presence of the pylon 101, in the air flow.

The existence of this wake has several disruptive consequences: it has a negative impact on performance in terms of fuel consumption; it has a negative impact on the noise level by constituting an additional source of noise, a source of annoying noise, especially at the time of take-off of the aircraft or the approach phase of the aircraft; it has a negative impact in mechanical and vibratory terms, creating an additional source of excitation.

In the state of the art, solutions have been proposed to try to minimize the impact of the wake created by the pylon on the blades of the propellers. Among these solutions, it has been proposed that schematically illustrated in Figure 3, in which a particular profile 301 pylon has been proposed. The particularity of the profile 301 resides in the shape of its trailing edge 302 situated at the base of the pylon, which has been truncated with respect to a conventional profile of the type shown in FIG. and an opening 303 which is used to blow the pulsed air 304 at said trailing edge 302. The air thus blown reduces or even compensate for the speed deficit at different points in the wake of air generated by the presence of the tower 301, speed deficit illustrated in Figure 2. For this purpose, the opening 303 is fed with pressurized air, for example by a nozzle of the aircraft, which is subject to relaxation until at ambient pressure, thereby obtaining blowing.

This solution, however, has a drawback related to the truncated form of the trailing edge. Such a shape is penalizing because it increases the shape of the wake mentioned above when the air is no longer blown through the opening. Or for reasons of fuel consumption, it is not possible to maintain the blowing during all phases of flight.

Thus, if the proposed solution is satisfactory during particular phases such as take-off or approach of the aircraft, which are phases of relatively short durations during which the blowing limits the negative impact in acoustic and vibratory terms of the wake born the presence of the pylon in front of the engine propellers, it poses a problem in terms of performance during the rest of the flight, because of the truncated form of the tower profile. GENERAL DESCRIPTION OF THE INVENTION The object of the invention offers a solution to the problem that has just been described by proposing a pylon of particular design making it possible to limit the damaging effects of the wake caused by the presence of the

tower and the positioning of the tower relative to the propellers of the aircraft engine with propeller propellers not keeled, while limiting an increased fuel consumption during certain phases of flight. To do this, the present invention proposes the use of a pylon whose trailing edge has an aerodynamically optimal shape, while maintaining the possibility of having a flow of air blown from the pylon. For this purpose, it is provided, in the towers according to the invention, to cause the flow of blown air to come not from the trailing edge of the pylon, but from the intrados (lower face) or extrados (upper face) faces in which openings were spared. Advantageously, it is expected that the openings in the lower and / or upper faces of the towers have variable sections that may change over time as a function of the flight phases observed by the aircraft, said openings being advantageously able to be closed.

The invention therefore essentially relates to a pylon for fixing an aircraft engine with propeller propellers not careened, said pylon ensuring the attachment of a propulsion system to the narrowing of the aircraft, said pylon having a trailing edge extended by a upper face and a lower face of said pylon, said pylon having an empty volume inside between the upper face and the lower face adapted to receive blown air, characterized in that the pylon has at least a first pierced zone having a first set openings, said first pierced zone being formed at the upper face and / or the lower face, and being able to let the air blown from the empty volume inside the outside of the pylon. Thus, the blown air does not come from a truncated trailing edge of the pylon, but from the upper and / or lower faces of said pylon, typically from areas at least about thirty centimeters from the end of the trailing edge. . In addition to the main features which have just been mentioned in the preceding paragraph, the pylon according to the invention may have one or more additional characteristics among the following,

considered individually or in any technically possible combination: the pylon comprises at least a first movable gate having a second set of openings, said at least one first movable gate being disposed at said at least one first pierced zone, said pylon having a first state, said open state, in which the openings of the at least one first movable grid are positioned opposite the openings of said at least one first pierced zone, and a second state, said closed state, in which the openings of said at least one pierced area is obstructed by solid areas of the at least one first movable gate; the pylon comprises a second movable gate with openings, and a second pierced zone with openings, the openings of the second movable gate being positioned facing the openings of the second pierced zone in the open state, and the openings of the second pierced zone being obstructed by solid areas of the second movable gate in the closed state, the first pierced zone and the second pierced zone being formed respectively on the upper face and on the lower face of the pylon; the first movable gate and the second movable gate are set in motion by independent actuators; each moving gate is able to move in movement within said pylon; each mobile grid is able to move in movement outside the pylon, along the skin of the pylon; each zone pierced with said pylon consists of a movable plate; each pierced zone is disposed in the downstream part of the pylon; the pylon has at least one intermediate state in which the openings of at least one of the mobile gates are partially obstructed by solid areas of the at least one first movable gate.

According to another aspect, the invention relates to an aircraft comprising the pylon according to the invention. The invention and its various applications will be better understood by reading the following description and examining the figures that accompany it. BRIEF DESCRIPTION OF THE FIGURES The figures are presented only as an indication and in no way limitative of the invention. The figures show: in FIG. 1, already described, a schematic representation of a pylon of the state of the art and its environment; FIG. 2, also already described, a schematic representation of the disturbances that can be experienced by the propellers of aircraft engines with propellant propellers that are not careened because of the existence of a wake in the air flow produced by the pylon positioning; - In Figure 3, also already described, a schematic representation of a pylon profile used in the state of the art to pulse air; in FIG. 4-A and in FIG. 4-B, various diagrammatic representations of a first example of a pylon according to the invention; - In Figure 5, schematic representations of different configurations of a second example of tower profile according to the invention. DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT OF THE INVENTION Unless otherwise specified, the same element appearing in different figures has a unique reference. Figures 4-A and 4-B show a first example of a pylon according to the invention in its preferred operating environment, namely aircraft engines with propeller propellers not careened respectively in top view and in sectional view.

In these figures, there is shown in plan view and schematically a pylon 401 providing the connection between the propulsion system 102 with its first propeller 104 and its second propeller 105, and the recess 103 of an aircraft. Pylon 401 has a trailing edge 403 which corresponds to the last zone of the pylon over which the air flow encountered by pylon 401 passes. As can be seen in FIG. 4-B, trailing edge 403 has an optimum aerodynamic profile. , no longer present, unlike the solution of the state of the art that has been described, truncated pellet. The fineness of the trailing edge 403 thus makes it possible not to increase the shape of the wake created by the presence of the pylon 401 in the flow of air reaching the propellers of the engine. In the invention, it is provided to provide at least one pierced zone 402 at an upper face 404 and / or a lower face 405 of the pylon 401. In the example shown, both the upper face 404 and the lower face 405 have such a pierced zone, which are designated respectively as the first pierced zone 402 and the second pierced zone 406. In other embodiments of the pylon according to the invention, a single pierced zone is produced, either on the face 404, or on the lower face 405. In the example shown, the pierced zones 402 and 406 are made directly by making openings 407 in the skin of the pylon 401, the skin of the pylon consisting of the material forming the thickness. between one of the visible faces of said pylon and an internal empty volume 408 formed between the upper face 405 and the lower face 404. The internal empty volume 408 receives the blown air, for example in as supplied with pressurized air through a nozzle of the aircraft, which can thus escape through the apertures 407. The shape, number and orientation of the openings 407 determines the air flow freed by the pylon. In the first embodiment described, provision is made to leave the openings 407 open at all times even when the blowing function is not filled by the pylon 401, which is the case in most of the flight phases of the aircraft. .

In order to optimize the aerodynamic aspect of the pylon according to the invention, it is advantageously provided that the pylon may pass from a closed state to an open state, and vice versa, the closed state corresponding to a situation where the openings of the pierced areas are obstructed, and the open state corresponding to a situation where the same openings are not obstructed. Such an advantageous solution is illustrated in FIG. 5. In this figure, in order to pass from an open state 501 to a closed state 502-1 and 502-2, it is proposed, in the example represented, to have, at the level of pierced zones 402 and 406, respectively a first movable gate 521 and a second movable gate 522 able to move so that openings 511 formed on said grids can adopt: - either a first position in which they are positioned opposite openings 407 of the pierced zone with which it is associated, thus placing the pylon in the open state 501; or a second position in which they are positioned in such a way that they are not facing the openings 407 of the pierced zone to which the gate is associated, thus placing the pylon in the closed state, corresponding to the references 502; 1 and 502-2. For this purpose, it can be provided that the movable gate is able to move in translation 503 towards the downstream part of the pylon along the pierced zone - the downstream part being formed by the part of the pylon placed near the trailing edge 403 typically between thirty centimeters and fifty centimeters from the trailing edge; it is advantageously provided that the movable gate is able to move in a radial direction 504 so that the solid portions 512 of the movable gates 521 and 522 are optimally blocking (closed state 502-2) the openings 407 of the pierced zone corresponding, the considered face of the pylon then having a smooth appearance. A set of intermediate states, corresponding to intermediate positions of the moving gates moving between the open state and the closed state, are furthermore defined, the openings 407 of each pierced zone being

left more or less open to obtain a desired flow of air, both in terms of flow in terms of orientation. In the example shown in FIG. 5, the mobile grids 521 and 522 are disposed inside the cavity 408. In other exemplary embodiments, provision is made to arrange the mobile grids outside the cavity 408. , said movable grids moving on the upper face 404 or on the lower face 405 outside the pylon. Advantageously, in the case where several mobile grids are present in the pylon according to the invention, and in particular when a first movable gate is present at the upper face and a second movable gate is present at the lower face. it is provided that the first movable gate and the second movable gate are controllable, for example by means of actuators, independently of one another.

In another embodiment, it is expected that the pierced zone is also movable, being for example constituted by a movable plate forming a portion of the upper or lower face of said pylon. The relative movements of the movable grid and the movable plate then to define more intermediate positions, and thus control the blowing flow. In the case of a plurality of mobile pierced zones, it is advantageously provided in the invention that the mobile pierced zones are controlled independently of one another. Thus, thanks to the pylons according to the invention, a fine trailing edge is preserved, advantageously corresponding to the conventional pylon profile in the flight phases without blowing, which makes it possible to suppress, even in the flight phases where the blowing function the pylon is not active, the drag penalty associated with a thick pellet at the trailing edge. It is thus possible to obtain an ad hoc distribution of the blowing between the intrados and extrados of the pylon, said distribution being adjustable according to the flight phases observed. The flow rate of the tower blowing function is controllable, in certain embodiments according to the invention, by

vary the effective opening surface of the mobile grids and / or movable plates, independently on the lower surface and on the upper surface.

Claims (10)

CLAIMS1 - Pylon (401) for fixing an aircraft engine propeller (104) propellant not careened, said pylon (401) ensuring the attachment of a propulsion system (102) to the necking (103) of the aircraft, said pylon (401) having a trailing edge (402) extended by an upper face (404) and a lower face (405) of said pylon (401), said pylon (401) having an interior empty space (408) between the face upper (404) and the lower face (405) adapted to receive blown air, characterized in that the tower (401) has at least one first pierced zone (402) having a first set of openings (407), said first pierced area (402) being provided at the top face (404) and / or the bottom face (405), and being able to let air blown from the interior void volume (408) escape to the outside of the pylon (401). 2- Pylon (401) for fixing according to the preceding claim characterized in that it comprises at least a first movable gate (521) having a second set of openings (511), said at least one first movable gate (521) being disposed at said at least one first pierced area (402), said pylon (401) having a first state (501), said open state, wherein the openings (511) of the at least one first movable gate (521) are positioned opposite the openings (407) of said at least one first pierced zone (402), and a second state (502-1; 502-2), said closed state, wherein the openings (407) of said at least a first pierced area (402) is obstructed by solid areas (512) of the at least one first movable gate (521). 3- Fixing pylon (401) according to the preceding claim characterized in that it comprises a second movable gate (522) with openings (511), and a second pierced zone (406) with openings (407), the openings (511) of the second movable gate (522) being positioned opposite the openings (407) of the second pierced zone (406) in the open state (501), and the openings (407) of the second zone 2971765 -12 - piercing (406) being obstructed by solid zones (512) of the second movable gate (522) in the closed state (502-1; 502-2), the first pierced zone (402) and the second pierced zone ( 406) being formed respectively on the upper face (404) and on the lower face (405) of the pylon (401). 5 4- Fixing pylon (401) according to the preceding claim characterized in that the first movable gate (521) and the second movable gate (522) are set in motion by independent actuators. 5. Pylon (401) according to any one of the preceding claims characterized in that each movable gate (521; 522) is adapted to evolve in motion (503; 504) within said pylon (401). 6. Pylon mounting (401) according to any one of claims 1 to 4 characterized in that each movable gate (521; 522) is adapted to move in movement outside the pylon (401), along the pylon skin (401). 15 7. A fastening pylon (401) according to any preceding claim characterized in that each pierced zone (402; 406) of said pylon (401) is constituted by a movable plate. 8- Pylon (401) according to any one of the preceding claims characterized in that each pierced zone (402; 406) is disposed in the downstream part of the pylon (401). 9- mounting pylon (401) according to any one of the preceding claims characterized in that said pylon (401) has at least one intermediate state in which the openings of at least one of the movable gates (521; 522) are partially obstructed by solid areas (512) of each movable gate (521; 522) considered. 10 - Aircraft characterized in that it comprises a fixing pylon (401) according to any one of the preceding claims. 30