Propulsion system comprising guide vanes attached to pivoting cowlings

Abstract

The invention relates to a propulsion system (1) with a longitudinal axis (X) comprising an internal structure (3); a hull (10) circumscribing at least a part of the internal structure (3) and comprising a fixed part (11) and hoods (13) pivoting relative to said fixed part (11), said hoods (13) being configured to be movable between an operating position (P1) in which the hoods (13) rest on each other, and a maintenance position (P2) in which at least one of the hoods (13) is pivoted radially away from the internal structure (3), so as to allow access to a part of the internal structure (3) located under said at least one of the hoods (13); at least one propeller (5); and a row of guide vanes (9) arranged on the hoods (13) of the hull (10) and integral with the hoods (13) of the hull (10). Figure 2

Description

Title of the invention: Propulsion system comprising guide vanes attached to pivoting covers. Technical field of the invention

[0001] The present invention relates to a propulsion system, for example used to propel an aircraft. State of the art

[0002] It is known from the prior art of turbofan engines that operate on the principle that a gas turbine engine drives a fan. The fan is generally located radially between an engine nacelle and the engine hub. An engine with unfaired rotor(s) or with unfaired rotor and stator operates differently, with the fan located radially to the axis of rotation of the central engine, outside the central engine nacelle. This allows the use of fan blades (or propellers) that can be larger and capable of acting on a greater volume of air than for a ducted turbofan engine. This can improve the bypass ratio (BPR) and propulsive efficiency compared to conventional engines.

[0003] Turbomachines comprising at least one unducted propeller are known by the English terms "open rotor," "open fan," or "unducted fan." Within this category of turbomachine, there are those with two counter-rotating unducted propellers (known by the English acronym UDF for "Unducted Dual Fan") or those with a single unducted propeller and a stator comprising several stator blades (known by the English acronym USF for Unducted Single Fan). The propeller or propellers forming the propulsion section may be located at the rear of the gas generator (or engine) so as to be of the pusher type or at the front of the gas generator so as to be of the tractor type. The use of an unfaired propeller allows the dilution rate to be increased very significantly without being penalized by the mass of the housings or nacelles intended to surround the blades of the propeller or blower.

[0004] Furthermore, turbomachinery with unducted propeller(s) are architectures that reduce fuel consumption. Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft and those already in service. requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been mobilizing for several years now to contribute to the fight against climate change.

[0005] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0006] A disadvantage of turbomachinery as described above, and in particular USF turbomachinery, is that they generate a considerable amount of noise. This noise originates from the gas generator but also from the interaction of the wake and the vortex generated by the winding of the streamlines at the tips of the propeller blades and the stator blades.

[0007] In order to reduce the noise generated by the turbomachine, solutions have been developed that involve the position and shape of the unfaired blades. For example, document FR3125797A1 discloses an aeronautical propulsion system comprising two sets of unfaired blades, where the second set of blades includes at least one leading edge with corrugations designed to limit the noise generated by the propulsion system. Document FR3114612A1 discloses a turbomachine with stator blades arranged to reduce the acoustic impact of the unfaired turbomachine while avoiding significant structural modifications to it.

[0008] Although these solutions are satisfactory in that they reduce the noise generated by the turbomachine, they impose design constraints on the turbomachine that hinder easy access to the engine for maintenance. Documents FR3119648A1 and FR3078998A1 disclose thrust reversers with movable grids comprising movable cowlings allowing access to the engine for maintenance; however, these cowlings are systematically positioned on the side opposite the propellers, which prevent easy access to the engine.

[0009] Thus, to perform maintenance on propeller engines and / or unshod stator blades, it is necessary to remove the panels screwed around the blades that remain in place. It is sometimes even necessary to remove the blades to access the engine under the cowlings. Such maintenance operations are very time-consuming and carry a risk of losing parts (such as screws or nuts), which can fall into the engine and damage it.

[0010] There is therefore a need to find a practical, safe and quick solution for carrying out maintenance operations on the engine parts located under the propeller blades and / or under the stator blades of a turbomachine.

[0011] Object and invention

[0012] The present invention aims to provide a solution that addresses all or part of the aforementioned problems.

[0013] This goal can be achieved through the implementation of a longitudinal axis propulsion system comprising: - a fixed internal structure; - a shell circumscribing at least a part of the internal structure and having an external surface defining an airflow along the external surface, said shell comprising a fixed part and hoods, the hoods being pivotable relative to said fixed part, said hoods being configured to be mobile between an operating position in which the hoods lean on each other, so as to ensure aerodynamic continuity of the airflow and a maintenance position in which at least one of the hoods is pivoted radially away from the internal structure, so as to allow access to a part of the internal structure located under said at least one of the hoods. - at least one propeller comprising a plurality of blades extending radially outside the internal structure, said at least one propeller being rotationally mobile; - a row of guide vanes arranged on the hull cowlings and downstream of at least one propeller in the direction of the airflow, said guide vanes extending radially outwards from the cowlings and being configured to straighten at least a part of the airflow from at least one propeller; the guide vanes being attached to the hull cowlings.

[0014] The above-described provisions make it possible to propose a propeller and guide vane propulsion system with simplified maintenance. Indeed, the ability to retract a portion of the hull containing the guide vanes allows easier access to the internal structure of the propulsion system, without requiring the removal of the guide vanes.

[0015] The propulsion system may also have one or more of the following characteristics, taken alone or in combination.

[0016] According to one embodiment, the guide vanes are configured to straighten the entire airflow.

[0017] According to one embodiment, the hoods comprise two semicircular hoods.

[0018] According to one embodiment, the annular row comprises sixteen guide vanes.

[0019] According to one embodiment, at least one propeller is driven in rotation by the internal structure.

[0020] According to one embodiment, the hoods are mounted to pivot relative to said fixed part by means of a hinge.

[0021] Thus, the guidance of the hoods in pivoting is facilitated.

[0022] According to one embodiment, the propulsion system further comprises a guidance system, the guide vanes being pivotally mounted relative to the guidance system around a pivot axis.

[0023] Thus, it is possible to orient the guide vanes around their extension axis by pivoting.

[0024] According to one embodiment, the orientation system includes a blade actuation member configured to orient the guide blades around the pivot axis.

[0025] According to one embodiment, the extension axis of the guide vanes is parallel or coincides with the pivot axis of the guide vanes.

[0026] In this way, it is possible to orient the guide vanes according to the flow requirements of the second airflow.

[0027] According to one embodiment, the orientation system comprises, for each hood, a guide belt associated with said hood and in sliding connection with said hood to which it is associated.

[0028] Thus, the guide belt allows the entire set of guide vanes to be oriented simultaneously when the guide belt is moved relative to the hoods.

[0029] According to one embodiment, the orientation system includes, for each hood, a guide belt in sliding connection with the internal structure.

[0030] Thus, the guide belt allows the entire set of guide vanes to be oriented simultaneously when the guide belt is moved relative to the internal structure.

[0031] According to one embodiment, the propulsion system further includes a locking device configured to lock the hoods in the operating position or alternatively to allow the hoods to be varied from the operating position to the maintenance position.

[0032] Thus, it is possible to ensure good locking of the hoods in the operating position, which makes the use of the propulsion system safer, while allowing the hoods to be opened in the maintenance position to access the internal structure.

[0033] According to one embodiment, the propulsion system includes at least one retaining element configured to allow the hoods to be held in the maintenance position.

[0034] Thus, it is possible for the user of the propulsion system to perform maintenance on it without the hoods returning to the operating position by the action of gravity.

[0035] According to one embodiment, the shell comprises a compressor section, a combustion chamber section and a turbine section arranged in series along the longitudinal axis.

[0036] According to one embodiment, at least one propeller is arranged upstream of the compressor section in the direction of the airflow.

[0037] According to one embodiment, the guide vanes are arranged at the compressor section, or downstream of the compressor section.

[0038] Thus, it is possible to allow air to be admitted via at least one propeller at the compressor section, while allowing the compression of the air before it enters the combustion chamber.

[0039] According to one embodiment, the guide vanes are fixed to the hull covers both in the operating position and in the maintenance position.

[0040] Thus, maintenance of the internal structure is facilitated, as the hoods and guide vanes can be moved simultaneously during a single operation.

[0041] Brief description of the drawings

[0042] Other aspects, objectives, advantages and features of the invention will become more apparent upon reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0043] [Fig-1] Fig. 1 is a schematic perspective view of a system of propulsion according to a particular embodiment of the invention, in which the hoods are in the operating position.

[0044] [Fig.2] The [Fig.2] is a schematic perspective and cross-sectional view of the propulsion system of the [Fig.1] in which the hoods are in the maintenance position.

[0045] [Fig.3] The [Fig.3] is a schematic cross-sectional view of a propulsion system according to a particular embodiment of the invention.

[0046] [Fig.4] The [Fig.4] is a schematic longitudinal cross-sectional view of the propulsion system of the [Fig.3].

[0047] [Fig.5] The [Fig.5] is a schematic cross-sectional view of a propulsion system according to a particular embodiment of the invention in which the hoods are in the operating position.

[0048] [Fig.6] The [Fig.6] is a schematic cross-sectional view of the propulsion system of the [Fig.5] in which the hoods are in the maintenance position.

[0049] [Fig.7] The [Fig.7] is a schematic longitudinal cross-sectional view of the propulsion system of the [Fig.5]. Detailed description

[0050] In the figures and throughout the description, the same reference numerals represent identical or similar elements. Furthermore, the various elements are not drawn to scale in order to enhance the clarity of the figures. Moreover, the different embodiments and variations are not mutually exclusive and may be combined.

[0051] As illustrated in Figures 1 to 6, the invention relates to a propulsion system 1 with a longitudinal axis denoted "X". This propulsion system 1 can serve as an aeronautical propulsion system, and can in particular form an aircraft turbojet engine, for example a turbofan engine.

[0052] The propulsion system 1 includes an internal structure 3 which is generally disposed at the center of the propulsion system 1 and having a central axis coinciding with the longitudinal axis X. Generally, the internal structure 3 is a gas generator comprising a compressor, a combustion chamber and a turbine.

[0053] The propulsion system also includes a shell 10 enclosing at least part of the internal structure 3. The shell 10 may include a compressor section 10a, a combustion chamber section 10b and a turbine section 10c arranged in series along the longitudinal axis X. For example, the compressor section 10a may surround one or more compressors (not shown), the combustion chamber section 10b may surround a combustion chamber (not shown), and the turbine section 10c may surround one or more turbines (not shown).

[0054] According to one embodiment, the shell 10 may internally define a passage for an internal airflow. Such a construction is not, however, limiting, and as shown in the figures, the shell 10 can be configured to enclose the internal structure 3 without defining a passage for an internal airflow.

[0055] The hull 10 has an external surface s 10 defining an airflow F2 along the external surface s 10. Hereafter, the terms "front" and "rear" are considered in a direction opposite to the main flow direction of the airflow F2 outside the hull 10. This main flow direction is generally parallel to the longitudinal axis X of the propulsion system 1. In contrast, the terms "upstream" and "downstream" are considered in the main flow direction of the airflow F2.

[0056] The hull 10 includes a fixed part 11 and cowlings 13. Generally, the fixed part 11 is attached to a mast 2 allowing the propulsion system 1 to be connected to the structure of an aircraft.

[0057] The cowlings 13 are mounted to pivot about said fixed part 11. Generally, the cowlings are mounted to pivot about one or more axes parallel to the longitudinal axis of the propulsion system 1. The cowlings 13 are further configured to be movable between an operating position PI in which the cowlings 13 rest on each other, so as to ensure aerodynamic continuity of the airflow F2, and a maintenance position P2 in which at least one of the cowlings 13 is pivoted radially away from the internal structure 3, so as to allow access to a portion of the internal structure 3 located under said at least one of the cowlings 13. Figures 1, 2A, 3, and 5 represent the propulsion system 1 with the cowlings 13 in the operating position PI, and Figures 2B and 6 represent the propulsion system 1 with the cowlings 13 in the maintenance position P2.The figures illustrate, in particular, embodiments in which the hoods 13 comprise two semicircular hoods 13. These hoods 13 can advantageously be pivotally mounted relative to the fixed part 11 by means of a hinge 15. Thus, the pivoting guidance of the hoods 13 is facilitated.

[0058] As can be seen in Figures 3, 5, and 6, a locking device 30 can be provided to lock the covers 13 in the operating position PI or, alternatively, to allow the covers 13 to be moved from the operating position PI to the maintenance position P2. Such a locking device 30 may, for example, comprise a male element (such as a ring) cooperating with a female element (such as a hook) to move between a locked and an unlocked position. This configuration is not, however, limiting, and other types of locking devices 30 may be provided that are suitable for providing a reversible locking function between the covers 13. In this way, it is possible to ensure that the covers 13 are securely locked in the operating position PI, while also allowing the covers 13 to be opened in the maintenance position P2 to access the internal structure 3.

[0059] It may also be advantageous to provide at least one retaining member 40 configured to hold the covers 13 in the maintenance position P2. Advantageously, the retaining member 40 may also be provided to assist in opening the covers 13 from the operating position PI to the maintenance position P2. For simplicity, Figures 3, 5, and 6 show only one retaining member 40. However, it is advantageous to provide one retaining member 40 to hold each cover 13 open in the maintenance position. P2. In this way, it is possible for the user of the propulsion system 1 to carry out maintenance on it without the hoods 13 returning to the operating position PI, in particular by the action of gravity.

[0060] The propulsion system 1 also includes at least one propeller 5, which comprises a plurality of blades 7 extending radially outside the internal structure 3. In order to avoid cluttering the representation in the figures, the reference numbers of the blades 7 have not been shown for each one. The propeller(s) 5 may be of the high-flow fan type and / or of the unducted rotor type, also known as unducted propellers. The corresponding established Anglo-Saxon terminology is sometimes used: open rotor / ultra-high bypass ratio, unducted fan type. In the non-limiting variant shown in Figures 1 and 2, the propulsion system 1 comprises a single propeller 5 arranged upstream of the internal structure, upstream of the compressor section 10a.Thus, it is possible to allow air to be admitted via at least one propeller 5 upstream of the compressor section 10a, while allowing the air to be compressed before entering the combustion chamber.

[0061] The absence of a nacelle or other housing surrounding the rotating blades 7 of the propeller 5 (i.e. of the unfaired fan) allows for a more fuel-efficient propulsion system at the cruising speeds of commercial aircraft.

[0062] Said at least one helix 5 is mobile in rotation, generally around the longitudinal axis X. For example, the at least one helix 5 is driven in rotation by the internal structure 3.

[0063] The propulsion system 1 also includes at least one row of guide vanes 9 (or OGVs, from the English "Outlet Guide Vane" according to established Anglo-Saxon terminology), for example, arranged in an annular pattern around the longitudinal axis X. These guide vanes 9 may be unfaired. These guide vanes 9 extend radially outwards from the cowlings 13 and are arranged on the cowlings 13 of the hull 10 and downstream of at least one propeller 5 in the direction of the airflow F2. The figures illustrate embodiments in which the annular row comprises sixteen guide vanes 9, the numerical references of which have not been given for each one, so as not to clutter the representation of the figures. These guide vanes 9 may extend along an axis of extension between a proximal part 9p and a distal part 9d.

[0064] These stator guide vanes 9 can be spaced circumferentially from each other, for example at the compressor section 10a of the casing 10, or downstream of it. These guide vanes 9 allow the airflow F2 to be straightened after it passes through the propeller 5. In other words, said guide vanes 9 are configured to guide at least a portion of the airflow F2 coming from at least one propeller 5. The guide vanes 9 are integral with the cowling covers 13 of the casing 10, particularly when they are moved from the operating position PI to the maintenance position P2. In other words, the guide vanes 9 can be pivotally fixed to the hoods 13 around the pivot axis of the hoods 13, so that they are fixed to the hoods 13 both in the operating position PI and in the maintenance position P2.

[0065] As illustrated in the figures, the guide vanes 9 can also be pivotally mounted on the hoods 13. Thus, it is possible to orient the guide vanes 9 around their extension axis by pivoting.

[0066] The shell 10 may also include a locking device 12, 14 configured to lock the covers 13 along the longitudinal axis X. As shown in Figures 4 and 7, the locking device 12, 14 may include a male element 12 projecting radially inward from the cover 13. The male element 12 may then be configured to cooperate with a female element 14 integral with the internal structure 3 and forming a groove with which the male element 12 cooperates.

[0067] Figures 3 to 7 illustrate two particular embodiments of the invention in which the propulsion system 1 further comprises a steering system 20. This steering system 20 may include a blade actuating member 27 configured to orient the guide vanes 9 around their extension axis. For example, such a blade actuating member 27 may include a motor driving the guide vanes 9 in rotation relative to the cowling 13. In this way, it is possible to orient the guide vanes 9 according to the airflow requirements F2.

[0068] Figures 3 and 4 illustrate a first embodiment in which the orientation system 20 comprises, for each hood 13, a guide belt 21 associated with said hood 13 and in a sliding connection with said hood 13 to which it is associated. Thus, the guide belt 21 makes it possible to simultaneously orient all the guide vanes 9 when the guide belt 21 is moved relative to the hoods 13.

[0069] Figures 5 to 7 illustrate a second embodiment in which the orientation system 20 comprises, for each hood 13, a guide belt 21 in sliding connection with the internal structure 3. Thus, the guide belt 21 makes it possible to simultaneously orient all the guide vanes 9 when the guide belt 21 is moved relative to the internal structure 3. In this case, and in order to allow each hood 13 to move from the operating position PI to the maintenance position P2, it is possible to provide a reversible fixed connection between the orientation system 20 and the internal structure 3. Such a connection can be made by a ball joint snapped into a corresponding collar, or by dog ​​clutches.

[0070] Although this is not shown (to simplify the reading of the figures), and regardless of the embodiment chosen, it is naturally possible to provide a guide belt 21 per hood 13.

[0071] All the arrangements described above make it possible to propose a propulsion system 1 with a propeller 5 and guide vanes 9 whose maintenance is facilitated. Indeed, the fact that a portion of the hull 10, including the guide vanes 9, can be retracted allows easier access to the internal structure 3 of the propulsion system 1, without requiring the removal of the guide vanes 9.

Claims

Demands

1. Propulsion system (1) with longitudinal axis (X) comprising: • a fixed internal structure (3); • a shell (10) circumscribing at least a part of the internal structure (3) and having an external surface (s10) defining an airflow (F2) along the external surface (s10), said shell (10) comprising a fixed part (11) and hoods (13), the hoods (13) being pivotable relative to said fixed part (11), said hoods (13) being configured to be movable between an operating position (PI) in which the hoods (13) rest on each other, so as to ensure aerodynamic continuity of the airflow (F2) and a maintenance position (P2) in which at least one of the hoods (13) is pivoted radially away from the internal structure (3), so as to allow access to a part of the internal structure (3) located under said at least one of the hoods (13).• at least one propeller (5) comprising a plurality of blades (7) extending radially outward from the internal structure (3), said at least one propeller (5) being rotationally movable; • a row of guide vanes (9) arranged on the cowlings (13) of the hull (10) and downstream of the at least one propeller (5) in the direction of the airflow (F2), said guide vanes (9) extending radially outward from the cowlings (13) and being configured to straighten at least a portion of the airflow (F2) from the at least one propeller (5); propulsion system (1) in which the guide vanes (9) are integral with the cowlings (13) of the hull (10).

2. Propulsion system (1) according to claim 1, wherein the hoods (13) are pivotally mounted relative to said fixed part (11) by means of a hinge (15).

3. Propulsion system (1) according to any one of claims 1 or 2, further comprising a steering system (20), the blades guide (9) being mounted to pivot relative to the orientation system (20) around a pivot axis.

4. Propulsion system (1) according to claim 3, wherein the steering system (20) comprises a blade actuation member (27) configured to orient the guide blades (9) around the pivot axis.

5. Propulsion system (1) according to any one of claims 3 or 4, wherein the guidance system (20) comprises for each hood (13), a guide belt (21) associated with said hood (13) and in sliding connection with said hood (13) to which it is associated.

6. Propulsion system (1) according to any one of claims 3 or 4, wherein the orientation system (20) comprises for each hood (13), a guide belt (21) in sliding connection with the internal structure (3).

7. Propulsion system (1) according to any one of claims 1 to 6, further comprising a locking device (30) configured to lock the hoods (13) in the operating position (PI) or alternatively permit variation of the hoods (13) from the operating position (PI) to the maintenance position (P2).

8. Propulsion system (1) according to any one of claims 1 to 7, comprising at least one retaining member (40) configured to allow the hoods (13) to be held in the maintenance position (P2).

9. Propulsion system (1) according to any one of claims 1 to 8, wherein the shell (10) comprises a compressor section (10a), a combustion chamber section (10b) and a turbine section (10c) arranged in series along the longitudinal axis (X).

10. Propulsion system (1) according to any one of claims 1 to 9, wherein the guide vanes (9) are integral with the cowlings (13) of the hull (10) both in the operating position (PI) and in the maintenance position (P2).

Images