AERONAUTICAL PROPELLER WITH RIGHTING

Abstract

The aeronautical propulsion system for an aircraft, comprising: - an outer casing; - a hub mounted pivoting relative to the outer casing about a principal axis (X); - a propeller mounted on the hub to rotate relative to the outer casing; and - a stator mounted on the outer casing downstream of the propulsion propeller along the principal axis (X), the stator extending around the principal axis (X), the stator comprising stator blades (114) each having: a stator leading edge (BA') having a belly (BA'_V), a stator inner radius, a stator outer radius, a stator blade height (H') equal to the difference between the stator outer radius and the stator inner radius, and a stator sweep angle at each point of the stator leading edge (BA').For at least one stator blade (114), the belly (BA'_V) of the stator leading edge (BA') is located between 10% and 30% of the stator blade height (H') measured from the stator inner radius (Ri'), and the stator sweep angle is greater than 30° over at least 40% of the stator blade height (H'). Figure for the abbreviation: Fig. 7.

Description

Title of the invention: AERONAUTICAL PROPELLER WITH RIGHTING Technical field of the invention

[0001] The present invention relates to an aeronautical propulsion system for an aircraft, as well as an aircraft comprising such an aeronautical propulsion system. Technological background

[0002] An aeronautical propulsion system for an aircraft, of the type comprising: - an external casing; - a hub mounted pivoting relative to the external casing around a main axis extending in an upstream-downstream direction of the aircraft; - a propeller mounted on the hub to rotate relative to the external casing; and - a straightener mounted on the external casing downstream of the propulsion propeller along the main axis, the straightener extending around the main axis, the straightener comprising stator blades each having: a stator leading edge having a belly, a stator internal radius, a stator external radius, a stator blade height equal to the difference between the stator external radius and the stator internal radius, and a stator sweep angle at each point of the stator leading edge.

[0003] The propeller is designed to drive a PHI airflow downstream.

[0004] The fixed stator is designed to straighten the airflow from the propeller in order to generate thrust that helps propel the aircraft forward. More specifically, this thrust is generated by deflecting the airflow over the stator blades, resulting in different inlet and outlet angles. The stator thus maximizes propulsive efficiency.

[0005] It is known that a vortex forms at the tip of each rotor blade of the propulsion propeller. These vortices impact the stator blades, so that each impacted portion of the stator blades becomes a source of noise. To reduce this noise, hereafter referred to as vortex interaction noise, it is known to truncate the stator blades so that the vortices pass, at least partially, over the truncated stator blades. It is further known to provide a high stator sweep angle at the tip of the stator blade to decouple or phase-shift the noise sources located there, excited by the vortex impact. Thus, providing a sweep angle The high stator at the top of the stator blade helps to reduce vortex interaction noise.

[0006] Furthermore, it is known that the flow over each rotor blade can undergo separation, particularly at the belly of the rotor blade, which produces wakes that also interact with the stator blades. Each part of the stator blades interacting with the wake thus becomes a source of noise, hereafter referred to as wake interaction noise. This separation on the rotor blades can occur during flight phases with high thrust on the rotor blades and / or flight phases with high angles of attack of the aircraft, such as takeoff. To reduce this wake interaction noise, it is known to provide a large sweep angle along the stator leading edge, again to decouple the noise sources located there, excited by the impact of the rotor blade wake.However, it is not possible to achieve a significant sweep angle over a large height, as the resulting stator blade geometry is difficult to implement in practice. Furthermore, wakes are primarily generated at the antinodes of the rotor blades. However, the antinodes of the stator blades are generally located at a radius close to that of the antinodes of the rotor blades. Therefore, the wakes reach the stator blades at their antinodes, where the sweep angle is not very large, which is unsuitable for reducing wake interaction noise.

[0007] The invention aims to provide an aeronautical propulsion system that addresses at least some of the aforementioned problems and constraints. Summary of the invention

[0008] An aeronautical propulsion system is therefore proposed for an aircraft of the aforementioned type, characterized in that, for at least one stator blade, the belly of the stator leading edge is located between 10% and 30% of the stator blade height from the internal stator radius, and in that the stator sweep angle is greater than 30° over at least 40% of the stator blade height.

[0009] Thanks to the invention, since the belly of the stator leading edge is offset towards the root of the stator blade, it is possible to design the stator blade with a significant sweep angle over a considerable height above the belly, i.e., a large radial portion of the stator blade. This downward offset of the belly also allows the wakes from the rotor blade bellies to reach the stator blades above their bellies, where the sweep angle is already significant. Thus, wake interaction noise is limited. Furthermore, due to the significant sweep angle over a considerable height, the stator blades are more curved downstream and can therefore have a less pronounced stator outer radius, allowing to allow the vortices to pass at least partially above. Thus, the vortex interaction noise is limited.

[0010] Furthermore, when the stator blades have variable pitch around a pitch axis, the presence of the belly at the root of the stator blade allows the portion of the stator blade at the belly to extend upstream of the pitch axis, while the tip portion extends downstream of the pitch axis. Thus, these two parts counterbalance each other to prevent the stator blade from having a center of gravity too far from the pitch axis. This reduces the moment generated by the aerodynamic forces around the pitch axis of the stator blade, which facilitates the modification of the pitch angle.

[0011] This invention makes it possible in particular to reduce the tonal noise for the blade passing frequencies (from the English "Blade Passing Frequency" or BPF), which is generated mainly on the lower half of the stator, and this at several operating regimes of the aeronautical propulsion, in particular in the take-off phase (from the English "Take-Off / Sideline") and in the climb phase ("Cutback" in English).

[0012] The invention may further include one or more of the following optional features, according to any technically possible combination.

[0013] Optionally, a stator trailing edge antinode is located in the first 35% of the stator blade height from the stator inner radius, preferably in the first 30%.

[0014] Optionally also, a belly of a stator trailing edge is located at a foot of the stator trailing edge and the stator trailing edge extends monotonically downstream from the foot of the stator trailing edge.

[0015] Optionally also, Ax / H' > 0.65, preferably greater than 0.70 where Ax = max{xBF'} - min{xBA'}, max{xBF'} being the position on the principal axis of the most downstream point of a stator trailing edge and min{xBA'} being the position on the principal axis of the antinode of the stator leading edge, and H' being the stator blade height.

[0016] Optionally also, the stator blade has a stator chord having a maximum at a radius equal to the radius, with respect to the main axis, of the belly of the stator leading edge to within 5% of the stator blade height.

[0017] Optionally also, the stator blade has a stator chord which, for any radius with respect to the main axis, is between 5% and 45% of the stator blade height.

[0018] Optionally also, the stator blade has a stator chord that is strictly decreasing with the radius relative to the main axis between 40% and 100% of the stator blade height, with a rate of decrease at least twice as great between 85% and 95% as between 40% and 60% of the stator blade height.

[0019] Optionally also, the stator blade having a stator chord, there is a ratio between the stator chord at the belly of the stator leading edge and a distance between the pitch axes of respectively a rotor blade of the propeller and the stator blade of the rectifier, between 0.1 and 0.8, preferably between 0.3 and 0.6.

[0020] Optionally also, at least two stator blades have different ratios between the stator chord at the belly of the stator leading edge and a different distance between alignment axes.

[0021] Optionally also, a difference between a radius with respect to the main axis of the belly of the stator leading edge and a point of the outer casing located between a beak and a foot of the stator leading edge is greater than 8% of the stator blade height and less than 30% of the stator blade height.

[0022] Optionally also, a radius, with respect to the main axis, of a belly of a rotor blade of the propeller is greater than a radius r, with respect to the main axis, of the belly of the stator blade, preferably greater than at least 20% of the stator blade height, preferably even greater than at least 25% of the stator blade height.

[0023] Optionally also, the stator blade has a negative stator sweep angle below the belly of the stator leading edge over a height of between 10% and 30% of the stator blade height.

[0024] Optionally also, the stator blade has a stator deflection angle greater than 20° over at least 60% of the stator blade height and negative over at least 10% of the stator blade height.

[0025] Optionally also, the stator blade has a stator deflection angle greater than 40° over at least 20% of the stator blade height on an upper panel of the rectifier.

[0026] Optionally also, with the stator blade having variable pitch, an airflow driven by the propeller exerts, over the whole of a flight domain of an aircraft equipped with the aeronautical propulsion system, a moment resulting from pressure and friction forces, around a stator pitch axis of less than 500N*m, in particular less than 400N*m.

[0027] Optionally also, the stator blade has a stator sweep angle of at least 45° at at least one point on the stator leading edge above the belly of the stator leading edge and / or between -20° and -5° at at least one point on the stator leading edge below the belly of the stator leading edge.

[0028] Optionally also, the stator leading edge has a tangential displacement in an azimuthal direction, having a local maximum or minimum on the side of an extrados of the stator blade located at a radius equal to the radius of the belly of the stator leading edge to within 35% of the stator blade height.

[0029] Optionally also, a relative height of the local maximum or minimum of the tangential displacement, defined as: k _ r <!Xt ~ ruA-P où rext lUxtremumy^ - rBA rrBA p is the radius where the local maximum or minimum of the tangential displacement is located, where rBÀjP is the radius of a foot of the stator leading edge, and where rBA'_T is the radius of a head of the stator leading edge, is between 5% and 50%.

[0030] Optionally also, a rotor blade of the propeller has a rotor trailing edge with serrations starting at a radius, relative to the main axis, substantially greater than a radius, relative to the main axis of the belly of the stator leading edge.

[0031] Optionally also, a rotor blade of the propeller has a rotor trailing edge with serrations starting at a radius, relative to the main axis, less than a radius, relative to the main axis, of the belly of the stator leading edge and extending over a height less than 60% of the stator blade height.

[0032] Optionally also, the stator blade having for each section perpendicular to a radius with respect to the main axis, a skeleton such as the mid-distance curve of an intrados and an extrados of the stator blade, the skeleton making, at the stator leading edge, an angle [3 with the main axis having an absolute value having a local minimum at a radius, with respect to the main axis, equal to a radius, with respect to the main axis of the belly of the stator leading edge to within 10% of the stator blade height.

[0033] Optionally also, the stator blade having for each section perpendicular to a radius with respect to the main axis, a skeleton such as the curve at mid-distance of an intrados and an extrados of the stator blade, the skeleton making, at the stator leading edge, an angle [3 with the main axis varying in absolute value, over the entire height of the stator blade, between 14° and 26° at most.

[0034] Optionally also, po . . rc, preferably even 77^ S~h^ <45' with S-top and S_bottom correspond to the mathematical area under a stator string as a function of a radius relative to the main axis, above and below the belly of the stator leading edge, respectively.

[0035] Optionally also, 7 q - SJumtJns rr, preferably still S_bas__bis J 2.7 < S high bis. c S bas bis < , where S_haut_bis and S_bas_bis correspond to the area mathematical function under a stator string as a function of a radius relative to the main axis, above and below the radius of the maximum string, respectively.

[0036] An aircraft comprising an aeronautical propulsion system according to the invention is also proposed. Brief description of the figures

[0037] The invention will be better understood with the aid of the following description, given solely by way of example and made with reference to the accompanying drawings in which: - Fig. 1 is a cross-sectional view of an aeronautical propulsion system according to the invention, - [Fig.2] is a side view of a rotor blade of a propeller of the aeronautical propulsion system of [Fig.1], - [Fig.3] is a front view of a leading edge of the rotor blade of [Fig.2], - [Fig.4] is a front view of a trailing edge of the rotor blade of [Fig.2], - [Fig. 5] is a view similar to [Fig. 3], further illustrating a cross-section of the rotor blade, - [Fig.6] is a view similar to [Fig.2] further illustrating a rotor deflection angle, - [Fig.7] is a side view of a stator blade of a rectifier of the aeronautical propulsion system of [Fig.1], - [Fig.8] is a front view of a stator leading edge of the stator blade of [Fig.7], - [Fig.9] is a front view of a stator trailing edge of the stator blade of [Fig.7], - [Fig. 10] is a view similar to [Fig. 8], further illustrating a cross-section of the stator blade, - [Fig. 1 1] is a view similar to [Fig. 7] further illustrating a stator deflection angle, - [Fig. 12] is a view similar to [Fig. 7] further illustrating a variation of the stator deflection angle as a function of a radius, - Figure 13 is a side view of two stator blades according to the invention, - [Fig. 14] is a view similar to [Fig. 7] further illustrating a variation of a stator string as a function of a radius, - Figure 15 is a side view of a stator blade according to the invention, - [Fig. 16] is a view similar to [Fig. 7] illustrating a most important point in upstream of a stator leading edge and the furthest downstream point of a stator trailing edge, - Figure 17 is a view similar to Figure 7, further illustrating a variation of a stator string as a function of a radius, according to three zones. - [Fig. 18] is a cross-section of the stator blade illustrating a skeleton of the stator blade and an angle [3] of the stator blade, - Figure 19 is a graph of the stator string as a function of the radius, and - Figure 20 is a graph illustrating a tangential displacement of the edge stator blade attack as a function of the radius, - [Fig.21] is a graph illustrating the variation of the angle [3] as a function of the radius. Detailed description of the invention

[0038] In the following description, when a characteristic applies to at least one element, it may also apply to all such elements. Similarly, when a characteristic applies to at least one value within a range, it may also apply to all values ​​within that range.

[0039] AERONAUTICAL PROPELLER

[0040] With reference to [Fig.1], an aeronautical propulsion unit 100 in which the invention is implemented will now be described.

[0041] The aeronautical propulsion unit 100 is designed to contribute to the propulsion of an aircraft. For example, it is intended to be supported by a pylon fixed to a wing or fuselage of the aircraft.

[0042] The aeronautical propulsion unit 100 is, for example, unducted (also known as USF), as in the illustrated example. However, the invention also applies to a ducted aeronautical propulsion unit, such as a turbofan.

[0043] The aeronautical propulsion unit 100 first of all comprises an external casing 102 and a hub 104 mounted pivoting relative to the external casing 102 around a main axis X, oriented from upstream to downstream.

[0044] Subsequently, the terms "upstream" and "downstream" will be used to specify the relative position of the elements of the aeronautical propulsion system 100 along the main axis X in a flow direction of an airflow PHI when the aircraft is propelled by the aeronautical propulsion system 100.

[0045] The hub 104 is thus, for example, located upstream of the external casing 102.

[0046] The aeronautical propulsion unit 100 further comprises a drive engine 105 of the hub 104. The motor 105 extends for example into the external casing 102. The motor 105 comprises for example at least one heat engine, in particular a turbomachine, a turbomotor, a turbojet or a turbofan, and / or at least one electric motor, and / or at least one hydrogen engine.

[0047] PROPELLER

[0048] The aeronautical propulsion unit 100 further comprises a propeller 106, for example unfaired, which is propulsive and mounted on the hub 104 so as to be pivotable relative to the external casing 102 around the main axis X. The propeller 106 is therefore driven in rotation around the main axis X by the motor 105 via the hub 104.

[0049] The propeller 106 is, for example, located upstream of the engine 105. In the case where the propeller 106 is unshod, such an arrangement is known as a "tractor" (from the English "puller"). Alternatively, the engine 105 could be in a "pusher" (from the English "pusher") arrangement.

[0050] During its rotation, the propeller 106 is designed to drive the airflow PHI downstream to propel the aircraft in flight. For this purpose, the propeller 106 comprises rotor blades 108 (for example, between 10 and 16, preferably between 12 and 14) arranged, for example, in a single annular row around the main axis X. The rotor blades 108 may, for example, all be identical and spaced angularly at regular intervals around the main axis X.

[0051] At least one rotor blade 108 is, for example, variable pitch, about a respective pitch axis Y, by means of a pitch change mechanism (PCM). The pitch of each rotor blade 108 is defined by a rotor pitch angle CAL about the rotor pitch axis Y. In a preferred embodiment, all the rotor blades 108 are variable pitch. This makes it possible to adapt the pitch of the rotor blades 108 and therefore the angle of incidence of the flow according to the flight phase.

[0052] Subsequently, the dimensions given for the rotor blades 108 will be valid for at least one pitch angle, preferably for all pitch angles within an interval of at least 10°.

[0053] Each rotor blade 108 has an external radius Re equal by definition to the distance between the main axis X and the point of the rotor blade 108 furthest from the main axis X. Each rotor blade 108 also has an internal radius Ri equal by definition to the distance between the main axis X and the point of the rotor blade 108 closest to the main axis X.

[0054] Generally, two adjacent rotor blades 108 may have different external rotor radii Re.

[0055] The propeller 106 thus has a diameter D equal to twice the external radius Re. This diameter D is also called the "motor diameter". The diameter D of the propeller 106 is, for example, between 1 m and 6 m, preferably between 3 m and 5 m.

[0056] RECTIFIER

[0057] The aeronautical propulsion unit 100 further includes a rectifier 112 (in English, "Outlet Guide Vane" or OGV), for example unshod, and mounted on the external casing 102 downstream of the propeller 106.

[0058] The rectifier 112 forms a stator fixed to the external housing 102 and extending around the main axis X, but not able to rotate around the latter. The rectifier 112 has stator blades 114 (for example, between 8 and 16, preferably between 10 and 14) arranged, for example, in a single annular row around the main axis X. Preferably, the number of stator blades 114 is different from the number of rotor blades 108, in order to reduce the noise of the aircraft propulsion 100. In particular, the number of rotor blades 108 is greater, for example, by at least two, than the number of stator blades 114. Indeed, if the number of rotor blades 108 and the number of stator blades 114 were equal, the wakes of the rotor blades 108 would interact simultaneously with the stator blades 114, which would increase the noise levels.The stator blades 114 may, for example, all be identical or different and spaced angularly in a regular or heterogeneous manner around the main axis X, so that at least two stator blades 114 have a different angular spacing around the main axis X.

[0059] For example, at least one stator blade 114 has variable pitch about a respective stator pitch axis Y', by means of a pitch change mechanism (PCM). The pitch of each stator blade 114 is defined by a stator pitch angle CAL' about the stator pitch axis Y'. In a preferred embodiment, all the stator blades 114 have variable pitch. This allows the pitch of the stator blades 114, and therefore the flow angle, to be adapted according to the flight phase.

[0060] The alignment axes Y, Y' are separated along the main axis X by a distance dHS. The stator alignment axis Y' can be inclined at an angle of inclination a' with respect to the radial direction. This can be useful for simplifying the integration of the stator blade 114 under the external housing 102 or for reducing the aerodynamic moments around said stator alignment axis Y'. When the angle of inclination a' is 40°, the distance dHS corresponds to the separation between the alignment axes Y, Y' along the main axis X measured at the root sections of the rotor blade 108 and the stator blade 114, as illustrated in [Fig. 1].

[0061] Subsequently, the dimensions given for the stator blades 114 will be valid for at least one pitch angle, preferably for all pitch angles within an interval of at least 10°.

[0062] Each stator blade 114 of the rectifier 112 has an external stator radius Re' equal by definition to the distance between the principal axis X and the point of the blade stator 114 furthest from the main axis X. Each stator blade 114 also has an internal stator radius Ri' equal by definition to the distance between the main axis X and the point of the stator blade 114 closest to the main axis X.

[0063] Generally, two adjacent stator blades 114 may have different external stator radii Re'.

[0064] The external casing 102 further includes a nozzle 116 for separating the primary and secondary flows, as well as a portion called a nozzle 118 between the nozzle 116 and the stator blades 114.

[0065] Rotor Blade

[0066] Subsequently, any one of the rotor blades 108 will be described in more detail, all the others being similar, for example.

[0067] With reference to [Fig.2], the rotor blade 108 first of all comprises a rotor leading edge BA where the airflow PHI arrives and a rotor trailing edge BF from which the airflow PHI departs.

[0068] The rotor trailing edge BF, for example, has serrations, that is, a succession of undulations or teeth (a succession of peaks and troughs). The serrations allow the wake of the propeller 106 to be mixed before interacting with the rectifier 112, in order to reduce wake interaction noise.

[0069] The rotor leading edge BA extends from a root BA_P to a tip BA_T. The rotor leading edge BA further includes a belly BA_V, which is the upstream point of the rotor leading edge BA along the principal axis X. This upstream point is distinct from the root BA_P, i.e., located at a greater height than the root BA_P. Thus, with this definition, a rotor blade whose upstream point is located at the root BA_P would not have a belly. Similarly, the rotor trailing edge BF extends from a root BF_P to a tip BF_T.

[0070] The rotor blade 108 can also be truncated, as in the illustrated example, i.e. there is a truncated section 202, for example straight, connecting the heads BA_T, BF_T. Alternatively, the rotor blade 108 could be non-truncated, in which case the heads BA_T and BF_T would coincide.

[0071] Thus, each rotor blade 108 has an external radius Re_BA at the rotor leading edge BA, which is the distance between the main axis X and the tip BA_T of the rotor leading edge BA, and an external radius Re_BF at the rotor trailing edge BF, which is the distance between the main axis X and the tip BF_T of the rotor trailing edge BF. The external rotor radius Re of the propeller 106 is therefore equal to the larger of the external radii Re_BA and Re_BF.

[0072] In addition, each rotor blade 108 has an internal radius Ri_BA at the rotor leading edge BA which is the distance between the main axis X and the root BA_P of the leading edge BA, as well as an internal radius Ri_BF at the rotor trailing edge BF which is the distance between the main axis X and the BF_P root of the rotor trailing edge BF. The internal rotor radius Ri of the propeller 106 is therefore equal to the smallest of the internal radii Ri_BA, Ri_BF.

[0073] In general, it is possible to define a radius r between the principal axis X and any point outside the principal axis X. In the following description, the radius r will designate, depending on the context, a radial direction (i.e. perpendicular to the principal axis X and passing through the principal axis X) passing through this point and / or a distance along this direction between the principal axis X and this point.

[0074] ROTARY RAY

[0075] With reference to [Fig.3], it is possible to position oneself on the rotor leading edge BA from a radius r extending from the principal axis X to each point of the rotor leading edge BA. For the rotor leading edge BA, the radius r thus varies from the internal radius Ri_BA of the rotor leading edge BA to the external radius Re_BA of the rotor leading edge BA. In particular, the antinode BA_V of the rotor leading edge BA is located at a radius r denoted r(BA_V).

[0076] With reference to [Fig. 4], similarly, it is possible to position oneself on the rotor trailing edge BF from the radius r extending from the principal axis X to each point of the rotor trailing edge BF. For the rotor trailing edge BF, the radius r thus varies from the internal radius Ri_BF of the rotor trailing edge BF to the external radius Re_BF of the rotor trailing edge BF.

[0077] Thus, to locate oneself on the rotor blade 108 in its entirety, it is possible to consider the radius r varying from the internal rotor radius Ri to the external rotor radius Re. The rotor blade 108 thus has a rotor blade height H (also called rotor span) equal to Re - Ri.

[0078] Thus, in the context of the rotor blade 108, the radius r will be expressed as a percentage of the rotor blade height H. The radius r can then vary from 0% of the rotor blade height H, when the radius r is the internal rotor radius Ri, up to 100% when the radius r is the external rotor radius Re.

[0079] The [Fig.5] is a section (also called an aerodynamic profile) at a radius r of the rotor blade 108. This section is taken along a plane P(r) perpendicular to the radius r and passes through a point BA(r) of the leading edge BA.

[0080] As can be seen, the rotor blade 108 has an intrados face 502 and an extrados face 504, respectively concave and convex, connected to each other, upstream, by the rotor leading edge BA and, downstream, by the rotor trailing edge BF.

[0081] ROTARY ROPE

[0082] When both the rotor leading edge BA and the rotor trailing edge BF are present in the section considered, the rotor leading edge BA and the rotor trailing edge BF can be connected by a rotor chord line 506 of which The orientation changes according to the radius r. The rotor leading edge BA and the rotor trailing edge BF are then separated, on the rotor chord line 506, by a distance, called rotor chord C, which can change according to the radius r.

[0083] ROTARY ARROW ANGLE

[0084] With reference to [Fig.6], it is also possible to define a rotor deflection angle F for the rotor blade 108, varying according to the radius r. By definition, the rotor deflection angle F is the angle between the radius r and the projection, in the plane of the radius r and the principal axis X (plane of the sheet for [Fig.6]), of the line 402 connecting the point 404 of the rotor leading edge BA at the considered radius r and the point 406 of the rotor leading edge BA at the radius r plus 1%, i.e. 1.0 Ir.

[0085] ROTARY THICKNESS

[0086] Each rotor blade 108 has a rotor thickness that varies according to the radius r. Preferably, this rotor thickness is maximum at a radius r less than 20% of the rotor blade height H, preferably less than 10% of the rotor blade height H: r < Ri + 0.2*H', preferably r < Ri + 0.1*H'. This ensures the mechanical strength of the rotor blades 108.

[0087] STATOR PALE

[0088] Subsequently, any one of the stator blades 114 will be described in more detail, all the others being able to be similar or different, depending on the embodiments, for example in the case of a variable truncation from one blade to the other azimutally, that is to say around the main axis X, to reduce the vortex interaction noise during the flight phases in incidence.

[0089] With reference to [Fig.7], the stator blade 114 has first of all a stator leading edge BA' where the airflow PHI from the propeller 106 arrives and a stator trailing edge BF' from which the airflow PHI departs.

[0090] The stator leading edge BA' extends from a foot BA'_P to a tip BA'_T. The stator leading edge BA' also has a slack BA'_V, which is the point of the stator leading edge BA' furthest upstream along the principal axis X. This furthest upstream point is distinct from the foot BA'_P, i.e., located at a greater height than the foot BA'_P. Thus, with this definition, a stator blade whose furthest upstream point is located at the foot BA'_P would not have a slack. Similarly, the stator trailing edge BF' extends from a foot BF'_P to a tip BF'_T. The stator trailing edge BF' also has a slack BF'_V, which is the point of the stator trailing edge BF' furthest upstream along the principal axis X.

[0091] The stator blade 114 can also be truncated, as in the illustrated example, i.e. there is a truncated section 702, for example straight, connecting the heads

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100] BA'_T, BF'_T. Alternatively, the stator blade 114 could be untruncated, in which case the heads BA'_T, BF'_T would be confused. Thus, each stator blade 114 has an external radius Re'_BA at the stator leading edge BA', which is the distance between the principal axis X and the tip BA'_T of the stator leading edge BA', and an external radius Re'_BF at the stator trailing edge BF', which is the distance between the principal axis X and the tip BF'_T of the stator trailing edge BF'. The stator external radius Re' of the rectifier 112 is therefore equal to the larger of the external radii Re'_BA and Re'_BF. Furthermore, the stator blade 114 has an internal radius Ri'_BA at the stator leading edge BA', which is the distance between the main axis X and the root BA'_P of the stator leading edge BA', and an internal radius Ri'_BF at the stator trailing edge BF', which is the distance between the main axis X and the root BF'_P of the stator trailing edge BF'. The internal stator radius Ri' of the stator blade 114 is therefore equal to the smaller of the two internal radii Ri'_BA and Ri'_BF. Thus, preferably, the rectifier 112 is unshod and the truncated section 702 of a stator blade 114 is such that: > Q Q5 In this way, the stator outer radius Re' is less than the rotor outer radius Re, so that the vortices of the propeller 106 can more easily pass, at least in part, over the rectifier 112. STATORIC RADIUS Referring to [Fig. 8], it is possible to position oneself on the stator leading edge BA' using the radius r extending from the principal axis X to each point on the stator leading edge BA'. For the stator leading edge BA', the radius r thus varies from the internal radius Ri'_BA of the stator leading edge BA' to the external radius Re'_BA of the stator leading edge BA'. Referring to [Fig. 9], it is similarly possible to position oneself on the stator trailing edge BF' using the radius r extending from the principal axis X to each point of the stator trailing edge BF'. For the stator trailing edge BF', the radius r thus varies from the internal radius Ri'_BF of the stator trailing edge BF' to the external radius Re'_BF of the stator trailing edge BF'. Thus, to locate the entire stator blade 114, it is possible to consider the radius r varying from the internal stator radius Ri' to the external stator radius Re'. The stator blade 114 therefore has a stator blade height H' (also called stator span) equal to Re' - Ri'. The [Fig. 10] is a section (also called an aerodynamic profile) at a radius r of the stator blade 114. This section is taken along a plane P(r) perpendicular to the radius r.

[0101] Thus, in the context of the stator blade 114, the radius r will be expressed as a percentage of the stator blade height H'. The radius r can then vary from 0% of the stator blade height H', when the radius r is the internal stator radius Ri', up to 100% when the radius r is the external stator radius Re'.

[0102] As can be seen, the stator blade 114 has an intrados face 1002 and an extrados face 1004, respectively concave and convex, connected to each other, upstream, by the stator leading edge B A' and, downstream, by the stator trailing edge BF'.

[0103] STATOR STRING

[0104] When the stator leading edge BA' and the stator trailing edge BF' are both present in the section considered, the stator leading edge BA' and the stator trailing edge BF' can be connected by a stator chord line 1006 whose orientation changes according to the radius r. The stator leading edge BA' and the stator trailing edge BF' are then separated, on the stator chord line 1006, by a distance, called the stator chord C', which can change according to the radius r.

[0105] STATORIC DRAFT ANGLE

[0106] With reference to [Fig. 11], it is also possible to define a stator deflection angle F' for the stator blade 114, varying according to the radius r. By definition, the stator deflection angle F' is the angle between the radius r and the projection, in the plane of the radius r and the principal axis X (plane of the sheet for [Fig. 11]), of the line 1102 connecting the point 1104 of the stator leading edge BA' at the considered radius r and the point 1106 of the stator leading edge BA' at the radius r plus 1%, i.e. l,01r.

[0107] STATIC THICKNESS

[0108] Each stator blade 114 has a stator thickness that varies according to the radius r. Preferably, this stator thickness is maximum at a radius less than: Ri' + 0.2*H', preferably Ri' + 0.1*H'. This ensures the mechanical strength of the stator blades 114.

[0109] DIMENSIONS

[0110] Various dimensioning characteristics of the propeller 106 and the rectifier 112 will now be described.

[0111] With reference to [Fig. 12], the antinode BA'_V of the stator leading edge BA' is located between 10% and 30% of the stator blade height H' from the internal stator radius Ri'. In addition, the stator deflection angle F' is preferably greater than 30° over at least 40% of the stator blade height H', on the upper panel (upper half) of the rectifier 112.

[0112] According to another possible characteristic, the stator deflection angle F' is always positive between the antinode BA'_V and the head BA'_T of the stator leading edge BA' and / or the stator deflection angle F' is always negative between the foot BA'_P and the antinode BA'_V of the stator leading edge BA'.

[0113] According to another possible characteristic, the BA'_V belly is located above the first 10% of the blade height H' measured from the inner radius Ri' of the stator blade 114. Indeed, if the BA'_V belly were located within the first 10% of the blade height H', it would be very close to the outer casing 102, causing aerodynamic losses. These aerodynamic losses impact the propulsive efficiency of the aircraft engine and may be linked to the occurrence of shocks near the root of the stator blades 114 during cruise, i.e., in flight at Mach 0.7 or higher. Furthermore, if the belly BA'_V was located in the first 10% of the blade height H', the manufacture of the stator blade 114 would be complicated, especially when the stator blade 114 is equipped with a heating mat and / or an added metal leading edge.

[0114] According to another possible feature, the antinode BF'_V of the stator trailing edge BF' is located within the first 35% of the blade height H' measured from the inner radius Ri, preferably within the first 30%. Thus, the antinode BF'_V is at a height relatively close to that of the antinode BA'_V. This simplifies the fabrication of the stator blade 114. For example, the stator plate 114 can be made from a composite material with fibers extending radially with respect to the X-axis, these fibers being called chains. In this case, the proximity of the antinodes BA'_V and BF'_V ensures continuity of the chains.

[0115] Furthermore, the proximity (in height) of the antinodes BA'_V and BF'_V can also contribute to interference between the noise generated at the leading edge BA' and that generated at the trailing edge BF', potentially having a beneficial effect on the acoustics. Indeed, by varying the stator string length with height, it is possible to modify the broadband frequency response of the stator blade noise. Thus, in some cases, to obtain the desired broadband frequency response, a weak string length is necessary. A weak string length can be more easily achieved with the antinodes BA'_V and BF'_V at similar heights.

[0116] Two examples of stator blade 114 according to the invention are illustrated in [Fig. 13].

[0117] With reference to Figure 14, as explained previously, the stator string C' varies as a function of the radius r. Thus, it is possible to calculate the mathematical area under the stator chord C' as a function of the radius r, above and below the antinode BA'_V of the stator leading edge BA': cRe , and S_haut = J ^BA Y^C\r)dr (Abà_v) S_bas-] C\r)dr Kl

[0118] With the BA'_V belly of the stator leading edge BA' close to the stator blade root 114 as proposed above, the upper area S_high will be greater than the area S_bas. Thus, according to another possible characteristic, 73^ <55, of preference still 27 < <45-

[0119] With reference to Figure 19, it is also possible to calculate Faire mathematically under the stator string C' as a function of the radius r, above and below the radius r(cmax) of the maximum string cmax: (Re , s and S high bis = \, .C^dr (rÀcmax) 5 bas bis=\ C'(r)dr

[0120] With the BA'_V belly of the stator leading edge BA' close to the stator blade root 114 as proposed above, the area S_haut_bis will be larger than the area S_bas_bis. Thus, according to another possible characteristic, 9 □ S_haut_bis _ S_bas_bis preferably still n -7 -. 4 c. < S Jxis bis <

[0121] According to another possible feature, the stator blade 114 has an activity factor FA between 40 and 225, preferably between 95 and 125 or between 90 and 160, the activity factor FA being defined as follows: 500,000 f'3 <. FA = D

[0122] The activity factor FA is thus low, because the maximum of the stator chord C' (which is by construction close to the belly BA'_V of the stator leading edge BA') is close to the root BA'_P of the leading edge BA' of the stator blade 114. Now, the larger the stator chord C' is in its lower part, the more the flow gyration downstream of the propeller is recovered, which provides an aerodynamic advantage, and the more it is possible to use serrations with a large amplitude in the lower part of the leading edge BA' of the stator blades 114, which provides an additional acoustic advantage. Indeed, the serrations of the leading edge BA' of the stator blade 114 are often more effective acoustically the greater their amplitude.

[0123] With reference to [Fig. 15], according to another possible feature, the sulcus BF'_V of the stator trailing edge BF' is located at the toe BF'_P of the stator trailing edge BF', and the stator trailing edge BF' extends monotonically downstream from the toe BF'_P of the stator trailing edge BF'. Indeed, the sulcus BF'_V of the stator trailing edge BF' is an area of ​​high mechanical stress concentration. Thus, with the stator trailing edge BF' extending only downstream, the presence of a dip or a bump on the stator trailing edge BF' is avoided, which improves its mechanical strength and simplifies the manufacturing process.

[0124] With reference to [Fig. 16], the stator blade 114 has an axial extension Ax defined as the difference between the position on the principal axis X of the point furthest The upstream position of the leading edge BA' (this position being denoted min{xBA'}) and the position on the principal axis X of the downstreammost point of the trailing edge BF' (this position being denoted max{xBF'}). min{xBA'} corresponds by definition to the antinode BA'_V of the stator leading edge BA'. However, even though max(xBF') most often corresponds to the tip BA'_T of the stator trailing edge BF', this is not always the case. Having a significant deflection F' at the tip of the stator blade 114 results in an increase in the axial extension Ax, particularly relative to the blade height H'. Thus, according to another possible characteristic, Ax / H' > 0.65, preferably greater than 0.70, where Ax = max{xBF'} - min{xBA'}. This allows for an optimal compromise between blade manufacturability, mechanical strength, mass, and noise reduction.

[0125] According to another possible feature, the stator string C' has a maximum at a radius, denoted r(cmax), equal to the radius r(BA'_V) of the antinode BA'_V of the stator leading edge BA' to within 5% of the stator blade height H': r(cmax) = r(BA'_V) + / - 0.05*H'. This allows the antinode BA'_V to be moved forward and thus increases the rearward stator sweep angle F' above the antinode BA'_V, which is advantageous for reducing wake interaction noise.

[0126] According to another possible characteristic, the stator string C' is, for any radius r, between 5% and 45% of the stator blade height H': 0.05 <-^<0.45'

[0127] This allows for stator string evolutions C' along the stator blade height H' compatible with a high stator deflection angle F' over a large part of the stator blade height H'.

[0128] According to another possible feature, with reference to [Fig. 17], the stator string C' evolves with the radius r according to three intervals, for example adjacent, of the radius r:

[0129] interval ZI (from 0% to at least 15% of the stator blade height H'): the string C' is strictly increasing with the radius r;

[0130] interval Z2 (from 40% up to at least 60% and at most 85% of the blade height H'): the stator string C' is strictly decreasing with the radius r; and

[0131] interval Z3 (from 85% up to 100% of the stator blade height H'): the stator string C' is strictly decreasing with the radius r, with a rate of decrease at least twice as large between 85% and 95% as between 40% and 60%, i.e.: CW,85*HyC'{0,95*H') _ * Cih,4*ffR"(0.6*fir), which can also be written: C{r=Ri^,S5*H,yC^=Ri'-¥0.95*H') ^C[r=RiA}Am^ O^IT > 0.2 H

[0132] This evolution of the stator string C' makes it possible to increase the sag F' locally near the head of the stator blade 114, which is interesting for minimizing vortex interaction noise.

[0133] According to another possible feature, in particular when the rectifier 112 is unfaired, there exists a ratio between the stator chord C' at the antinode BA'_V of the stator leading edge BA' and the distance dHS between the pitch axes Y, Y', between 0.1 and 0.8, preferably between 0.3 and 0.6: g C'{r(BA'_V)) gg, preferably: 'dHS'

[0134] Thus, the stator chord C' at the antinode BA'_V of the stator leading edge BA' is not too small, so that the rectifier 112 can properly compensate for the gyration from the propeller 106, nor too large so as not to negatively impact the mass and / or size. The stator chord C' at the antinode BA'_V of the stator leading edge is expressed with respect to the distance dHS, as this is the characteristic distance of wake interaction noise.

[0135] In a particular embodiment, at least two stator blades 114 of the rectifier 112 have a different ratio. This allows for taking into account takes into account the installation and incidence effects and therefore adapts the chord at the belly level according to the loading of the stator blades 114, which varies according to their azimuthal position around the main axis X.

[0136] According to another possible characteristic, the radius r(BA_V) of the belly BA_V of the rotor blade 108 is greater than the radius r(BA'_V) of the belly BA'_V of the stator blade 114, preferably: r(BA_V) > r(BA'_V) + 0.2*H', more preferably r(BA_V) > r(BA'_V) + 0.25*H'. This makes it possible to reduce wake interaction noise, particularly when the rotor blades are loaded and exhibit separation from the position of the belly BA_V of the leading edge BA.

[0137] According to another possible feature, the stator deflection angle F' is greater than 20° over at least 60% of the stator blade height H' (i.e. 0.6*H') and the stator deflection angle F' is negative over at least 10% of the stator blade span (0.1*H').

[0138] According to another possible feature, the stator deflection angle F' is greater than 40° over at least 20% of the stator blade height H'.

[0139] Thus, the stator deflection angle F' is very high over a very large part of the stator blade height H'.

[0140] According to another possible feature, when the stator blade 114 has variable pitch, the flow PHI exerts, over the entire flight domain, a moment resulting from pressure and friction forces on the stator blade 114, around the axis The pitch Y' must be less than 500 N*m, and in particular less than 400 N*m. This ensures the proper functioning of the hydraulic system and the actuators responsible for adjusting the pitch of the stator blade 114 according to the operating point in order to maximize aerodynamic performance (preventing separation) and reduce noise. If the moments are too high, the system would not be able to rotate the stator blade 114 to adjust the pitch, or the system would be too heavy and therefore impractical for use on an aircraft engine.

[0141] According to another possible feature, the stator sag angle F' is at least 45° at at least one point on the stator leading edge BA' above the antinode BA'_V of the stator leading edge BA'. This helps to reduce vortex interaction noise.

[0142] According to another possible feature, the stator sweep angle F' is between -20° and -5° at at least one point on the stator leading edge BA' below the belly BA'_V of the stator leading edge BA'. This allows the belly BA'_V to be positioned close to the stator blade root BA'_P and the outer casing 102.

[0143] According to another possible feature, the serrations of the rotor trailing edge BF begin at a radius smaller than the radius r(BA'_V) of the antinode BA'_V of the stator leading edge BA'. The serrations allow for better mixing of the propeller wake and thus reduce interaction noise in a region with a low stator sweep angle F' (for example, the absolute value of the sweep angle is less than 20°: IF'I < 20°) around the antinode BA'_V of the stator leading edge BA'.

[0144] According to another possible feature, the serrations of the rotor trailing edge BF start at a radius substantially greater than the radius r(BA'_V) of the belly BA'_V of the stator leading edge BA'.

[0145] In this case, the advantage is to place the serrations at the rotor trailing edge BF in an area with low but positive stator deflection (for example, 5° < F' < 20°) to help reduce noise while limiting the radial extension of the serrations at the rotor trailing edge BF, which simplifies the manufacturing process and improves the mechanical strength of the rotor blade 108.

[0146] According to another possible feature, the serrations of the rotor trailing edge BF extend over a height less than 60% of the stator blade height H'. This is useful for reducing noise while limiting the radial extension of the serrations on the rotor trailing edge BF, which simplifies the manufacturing process and improves the mechanical strength of the rotor blade 108.

[0147] According to another possible feature, the serrations of the rotor trailing edge BF are only provided above 10% of the rotor blade height H and below 60% of the stator blade height H', in other words, the serrations of the rotor trailing edge BF are only provided in Ri + 0, l*H < r < Ri' + 0.6*H'. This allows for better dissipation of the propeller 106's wakes before they interact with the BA'_V antinodes of the stator leading edges BA'. The presence of serrations below 10% of the rotor blade height H can influence the primary flow supply, which can degrade the performance of the aircraft propulsion system. The presence of serrations below 60% of the rotor blade height H reduces wake interaction noise on the lower part of the stator where the antinode and areas of lowest sag are located, thus maximizing acoustic gains. This is also useful for improving the mechanical strength of the blades by limiting the number of undulations on the rotor trailing edge BF.

[0148] According to another possible feature, at least one crest and / or one trough of the serrations is located at the radius r(BA'_V) of the BA'_V antinode of the stator leading edge BA', within 5% of the stator blade height H'. This maximizes the decorrelation of noise sources near the BA'_V antinode of the leading edge where the stator sweep angle F' is small and wake interaction noise is significant.

[0149] With reference to [Fig. 18], for each cross-section of the stator blade 114, it is possible to define a skeleton 1902, as the mid-distance curve of the intrados 1002 and the extrados 1004. The skeleton 1902 can, for example, be obtained, as illustrated in [Fig. 18], as the set of centers of circles inscribed in the cross-section, i.e., flush with both the intrados 1002 and the extrados 1004. At the stator leading edge BA', the skeleton 1902 makes an angle [3 with the X axis (|3 is thus the angle of the tangent to the skeleton 1902 at the stator leading edge BA') which varies according to the radius r, in order to adapt the profiles to the over-incidences / under-incidences linked to the effects of positive / negative sweep, respectively. For example, increasing the sweep angle F' at the stator leading edge BA' increases the local impact on the aerodynamic profiles of the stator blade 114.This over-incidence must therefore be compensated by an increase in the absolute value of the angle [3, which realigns the skeleton with the incident flow and avoids separations that can deteriorate aerodynamic performance.

[0150] With reference to [Fig. 21], according to another possible characteristic, the absolute value of angle [3] exhibits a local minimum at a radius r equal to the radius r(BA'_V) of the antinode BA'_V of the stator leading edge BA' to within 10% of the stator blade height H'. Indeed, the sag at the antinode is zero, so there is no over-incidence of the flow to compensate for (the incidence being the angle of the airflow with respect to the principal axis X). Thus, angle beta can be a local minimum.

[0151] According to another possible characteristic, the absolute value of the angle [3 varies, over the entire height of the stator blade H', between 14° and 26° at most.

[0152] According to another possible characteristic, the difference in radius between the antinode BA'_V at the stator leading edge BA' and the point of maximum radius r located on the portion The distance between the leading edge 118 of the outer casing 102 (between the leading edge 116 and the base of the stator blade 114) is greater than 0.08*H' and less than 0.3*H'. Indeed, a certain distance must be maintained between the belly of the leading edge BA' and the leading edge portion 118 to avoid separation, blockages of the flow and therefore aerodynamic losses, particularly at high speed (cruise, Mach > 0.7).

[0153] According to another possible feature, the deflection angle is negative below the BA'_V belly of the stator leading edge BA' over a height between 10% and 30% of the stator blade height H'. This allows for a strong negative deflection over a small portion of the lower panel of the OGV, which makes it possible to simulate the operation of a serration tooth or apex at the belly and thus reduce noise.

[0154] According to another possible feature, the leading edge BA' of the stator blade 114 has a tangential displacement in the azimuthal direction yBA' having a local maximum or minimum yBA'ext on the upper surface near the belly (as illustrated in [Fig. 20]) to maximize noise reduction. “Near the belly” means that this local maximum is located at a radius rext equal to the radius of the belly of the stator leading edge BA' to within 35% of H'.

[0155] According to another possible characteristic, the relative height of the local maximum or minimum of yBA', defined as », _ will be nextrentumyBA. ~ rBÀrrBÀy preferably between 5% and 50%.

[0156] According to another possible characteristic, the relative amplitude of the yBA law defined as will be between 0% and 10%, preferably between 1% and 5%. H

[0157] CONCLUSION

[0158] In conclusion, it should be noted that the invention is not limited to the embodiments described above. It will indeed be apparent to those skilled in the art that various modifications can be made to the embodiments described above, in light of the information just disclosed to them.

[0159] In the detailed presentation of the invention given above, the terms used shall not be interpreted as limiting the invention to the embodiments set forth in this description, but shall be interpreted as including all equivalents which can be foreseen by a person skilled in the art by applying their general knowledge to the implementation of the teaching which has just been disclosed to them.

Claims

Demands

1. Aeronautical propulsion (100) for an aircraft, comprising: - an outer casing (102); - a hub (104) mounted pivotally relative to the outer casing (102) about a principal axis (X) extending in an upstream-downstream direction of the aircraft; - a propeller (106) mounted on the hub (104) so ​​as to rotate relative to the outer casing (102);and - a rectifier (112) mounted on the external casing (102) downstream of the propulsion propeller (106) along the main axis (X), the rectifier (112) extending around the main axis (X), the rectifier (112) comprising stator blades (114) each having: a stator leading edge (BA') having a belly (BA'_V), a stator internal radius (Ri'), a stator external radius (Re'), a stator blade height (H') equal to the difference between the stator external radius (Re') and the stator internal radius (Ri'), and a stator sweep angle (F') at each point of the stator leading edge (BA'); characterized in that, for at least one stator blade (114), the belly (BA'_V) of the stator leading edge (BA') is located between 10% and 30% of the stator blade height (H') from the stator internal radius (Ri'), and in that the stator sweep angle (F') is greater than 30° over at least 40% of the stator blade height (H').;

2. Aeronautical propulsion (100) according to claim 1, wherein a belly (BF'_V) of a stator trailing edge (BF') is located in the first 35% of the stator blade height (H') from the stator inner radius (Ri'), preferably in the first 30%.

3. Aeronautical propulsion (100) according to claim 1 or 2, wherein a belly (BF'_V) of a stator trailing edge (BF') is located at a foot (BF'_P) of the stator trailing edge (BF') and the stator trailing edge (BF') extends monotonically downstream from the foot (BF'_P) of the stator trailing edge (BF').

4. Aeronautical propulsion (100) according to any one of claims 1 to 3, wherein: Ax / H' > 0.65, preferably greater than 0.70 where Ax = max{xBF'} - min{xBA'}, max{xBF'} being the position on the principal axis (X) of the most downstream point of a stator trailing edge (BF') and min{xBA'} being the position on the principal axis (X) of the antinode (BA'_V) of the stator leading edge (BA'), and H' being the stator blade height (H').

5. Aeronautical propulsion (100) according to any one of claims 1 to 4, wherein the stator blade (114) has a stator chord (C') having a maximum at a radius equal to the radius, with respect to the principal axis (X), of the belly (BA'_V) of the stator leading edge (BA') to within 5% of the stator blade height (H').

6. Aeronautical propulsion (100) according to any one of claims 1 to 5, wherein the stator blade (114) has a stator chord (C') that is strictly decreasing with the radius (r) with respect to the principal axis (X) between 40% and 100% of the stator blade height (H'), with a rate of decrease at least twice as great between 85% and 95% as between 40% and 60% of the stator blade height (H').

7. An aeronautical propulsion system (100) according to any one of claims 1 to 6, wherein, the stator blade (114) having a stator chord (C'), there exists a ratio between the stator chord (C') at the belly (BA'_V) of the stator leading edge (BA') and a distance (dHS) between the pitch axes (Y, Y') of a rotor blade (108) of the propeller (106) and the stator blade (114) of the stator (112), respectively, of between 0.1 and 0.8, preferably between 0.3 and

8. v,u. Aeronautical propulsion (100) according to claim 7, wherein at least two stator blades (114) have different ratios between the stator chord (C') to the belly (BA'_V) of the stator leading edge (BA') and a distance (dHs) between pitch axes (Y, Y').

9. Aeronautical propulsion (100) according to any one of claims 1 to 8, wherein a difference between a radius with respect to the principal axis (X) of the belly (BA'_V) of the stator leading edge (BA') and a point of the outer casing (102) located between a beak (116) and a foot (BA'_P) of the stator leading edge (BA') is greater than 8% of the stator blade height (H') and less than 30% of the stator blade height (H').

10. Aeronautical propulsion (100) according to any one of claims 1 to 9, wherein a radius, with respect to the principal axis (X), of a belly (BA_V) of a rotor blade (108) of the propeller (106) is greater than a radius r, with respect to the principal axis (X), of the belly (BA'_V) of the stator blade (114), preferably greater than at least 20% of the stator blade height (H'), preferably even greater than at least 25% of the stator blade height (H').

11. Aeronautical propulsion (100) according to any one of claims 1 to 10, wherein the stator blade (114) has a negative stator sweep angle (F') below the belly (BA'_V) of the stator leading edge (BA') over a height between 10% and 30% of the stator blade height (H').

12. Aeronautical propulsion (100) according to any one of claims 1 to 11, wherein the stator blade (114) has a stator sweep angle (F') greater than 20° over at least 60% of the stator blade height (H') and negative over at least 10% of the stator blade height (H').

13. Aeronautical propulsion (100) according to any one of claims 1 to 12, wherein the stator blade (114) has a stator sweep angle (F') greater than 40° over at least 20% of the stator blade height (H') on an upper panel of the rectifier (112).

14. Aeronautical propulsion (100) according to any one of claims 1 to 13, wherein, the stator blade (114) being variable pitch, an airflow (PHI) driven by the propeller (108) exerts, over the whole of a flight domain of an aircraft equipped with the aeronautical propulsion (100), a moment resulting from pressure and friction forces, around a stator pitch axis (Y') of less than 500N*m, in particular less than 400N*m.

15. Aeronautical propulsion (100) according to any one of claims 1 to 14, wherein the stator blade (114) has a stator sweep angle (F') of at least 45° at at least one point on the stator leading edge (BA') above the belly (BA'_V) of the stator leading edge (BA') and / or between -20° and -5° at at least one point on the stator leading edge (BA') below the belly (BA'_V) of the stator leading edge (BA').

16. Aeronautical propulsion (100) according to any one of claims 1 to 15, wherein the stator leading edge (BA') has a tangential displacement (yBA') in an azimuthal direction, having a local maximum or minimum (yBA'ext) on the side of an extrados of the stator blade (114) located at a radius (rext) equal to the radius of the belly of the stator leading edge (BA') to within 35% of the stator blade height (H').

17. Aeronautical propulsion (100) according to claim 16, wherein a relative height of the local maximum or minimum (yBA'ext) of the tangential displacement (yBA'), defined as: ~ rBA_p where rext is the radius where the local maximum or minimum (yBA'ext) of the tangential displacement (yBA') is located, where rBA'_p is the radius of a foot (BA'_P) of the stator leading edge (BA'), and where rBA'_P is the radius of a head (BA'_P) of the stator leading edge (BA'), is between 5% and 50%.

18. Aeronautical propulsion (100) according to any one of claims 1 to 17, wherein a rotor blade (108) of the propeller (106) has a rotor trailing edge (BF) with serrations starting at a radius, with respect to the principal axis (X), substantially greater than a radius, with respect to the principal axis (X), of the belly (BA'_V) of the stator leading edge (BA').

19. Aeronautical propulsion (100) according to any one of claims 1 to 18, wherein a rotor blade (108) of the propeller (106) has a rotor trailing edge (BF) with serrations starting at a radius, with respect to the principal axis (X), less than a radius, with respect to the principal axis (X),) of the belly (BA'_V) of the stator leading edge (BA') and extending over a height less than 60% of the stator blade height (H').

20. Aeronautical propulsion (100) according to any one of claims 1 to 19, wherein, the stator blade (114) having for each section perpendicular to a radius with respect to the principal axis (X), a skeleton (1902) as the mid-distance curve of an intrados (1002) and an extrados (1004) of the stator blade (114), the skeleton (1902) making, at the stator leading edge (BA'), an angle [3 with the principal axis (X) having an absolute value having a local minimum at a radius, with respect to the principal axis (X), equal to a radius, with respect to the principal axis (X) of the belly (BA'_V) of the stator leading edge (BA') to within 10% of the stator blade height (H').

21. Aeronautical propulsion (100) according to any one of claims 1 to 20, wherein the stator blade (114) having for each section perpendicular to a radius with respect to the principal axis (X), a skeleton (1902) as the mid-distance curve of an intrados (1002) and an extrados (1004) of the stator blade (114), the skeleton (1902) making, at the stator leading edge (BA'), an angle [3 with the principal axis (X) varying in absolute value, over the entire height of the stator blade (H'), between 14° and 26° at most.

22. Aeronautical propulsion (100) according to any one of claims 1 to 21, wherein qt Sjtaut c, preferably Sbas 2 7 < <45, with S_haut and S_bas correspond to the mathematical area under a stator chord (C') as a function of a radius (r) with respect to the principal axis (X), above and below the belly (BA'_V) of the stator leading edge (BA'), respectively.

23. Aeronautical propulsion (100) according to any one of claims 1 to 22, wherein 9 has SJtautJns - _ S_bas_bis preferably still ot S_haut_his . -, with S_haut_bis and %7 SjbasJris S_bas_bîs correspond to the mathematical area under a stator chord (C') as a function of a radius (r) with respect to the principal axis (X), above and below the radius (r(cmax)) of the maximum chord (cmax), respectively.

24. Aircraft comprising an aeronautical propulsion system (100) according to any one of the preceding claims.

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