Conduit-free thrust generating assembly including rectified stator

Abstract

The invention relates to a rectifying stator (5) of a ductless thrust generating assembly (3), comprising a plurality of blades (7), each blade having:-a tip (11) and a radially inner boundary (10) corresponding to an intersection between a casing (8) of a turbine engine (1) and the blade (7); -a skeleton (16); and-a deviation (#) of the profile corresponding to the absolute value of the difference between the tangent to the skeleton (16) at the leading edge (14) of the blade and the tangent to the skeleton (16) at the trailing edge (15) of the blade (7), between 20 DEG and 45 DEG at the radially inner boundary (10) of the blade (7) and between 10 DEG and 40 DEG at the tip (11) of the blade (7).

Description

Technical Field

[0001] The present invention relates generally to the field of turbine engines, and more particularly to outer guide vanes for unducted thrust generating assemblies of turbine engines. The present invention applies more particularly, in a non-limiting manner, to turbine engines having a high bypass ratio (generally greater than 12, preferably greater than 18). Background Art

[0002] An Unducted Single Fan (USF) type turbine engine comprises, from upstream to downstream in the direction of the air flow through the turbine engine, a rotating propeller and outer guide vanes.

[0003] In general, propellers, known as "conventional" single-stage turboprop propellers, and counter-rotating propeller pairs are loaded at the upper portion of the blades, maximizing the work of this portion of the blades to increase the flow deviation. This, in fact, enables full use of the speed triangulation at the blade tip, which favors the driving thrust. Furthermore, this allows minimizing the induced losses of the blades (i.e. the losses resulting from the radial distribution of the blade loads), which can be achieved by vortices at the blade tip and generally by modifying the triangulation of the air flow, which tends to reduce the driving thrust.

[0004] The applicant has noticed that loading the propeller at the blade head also has the effect of loading the outer guide vanes at the blade tip. An increase in the load means an increase in the deflection, which also means an increase in the residual swivel at the propeller outlet, and therefore means that the outer guide vanes must be strongly deflected to re-axialize the air flow. However, in this region of the blade, the robustness of the outer guide vanes is lower. The robustness of the outer guide vanes at a given radius is here to be understood as the ratio between the chord of the blade and the distance between two adjacent blades (chord to distance measured at the radius in question). However, the lower the robustness of the outer guide vanes, the less they are able to straighten the flow, which means a reduction in aerodynamic performance, an increase in the noise level from an acoustic point of view (due to the interaction between the propeller and the outer guide vanes at the blade tip), and high mechanical stresses of the outer guide vanes at the blade tip.

[0005] In order to eliminate the noise at the head of the unducted blades, document FR 2 938 502 proposes to equip the blades of the propeller with guide fins. However, this document relates to a turbine engine comprising a counter-rotating propeller, rather than a propeller followed by an external guide vane. Moreover, the proposed solution has the effect of deviating the vortex radially outside the downstream blades, and therefore, applying this solution to a thrust generating assembly comprising static external guide vanes has the effect of reducing the amount of air flow straightened by the external guide vanes and thus reducing the aerodynamic performance of the turbine engine. Summary of the invention

[0006] The purpose of the present application is to overcome the above-mentioned drawbacks by proposing an outer guide vane capable of improving the aerodynamic performance of the turbine engine and reducing the noise generated by the thrust generating assembly without increasing the mechanical stresses at the blade tip of the outer guide vane.

[0007] To this end, according to a first aspect, there is provided an outer guide vane for an unducted thrust generating assembly of a turbine engine, the outer guide vane comprising a plurality of blades, each blade having:

[0008] - a tip and a radially inner boundary corresponding to the intersection between the casing and the blade of the turbine engine;

[0009] a skeleton corresponding to an imaginary line extending from the leading edge to the trailing edge of the blade, the imaginary line being equidistant between the pressure surface and the suction surface of the blade; and

[0010] - a deviation of the profile (δ), which corresponds to the absolute value of the difference between the tangent of the skeleton at the leading edge of the blade and the tangent of the skeleton at the trailing edge of the blade, which deviation is between 20° and 45° at the radial inner boundary of the blade and between 10° and 40° at the tip of the blade.

[0011] In one embodiment, the maximum deviation value is obtained between 0% and 40% of the height of the blade (the height being understood as the difference between the maximum radius at the blade tip and the minimum radius of the intersection between the casing of the turbine engine and the blade).

[0012] Some preferred but non-limiting features of the outer guide vanes according to the first aspect are the following features taken alone or in combination:

[0013] - the deviation of the profile of each blade at the radially inner edge of the blade is between 25° and 35°;

[0014] - the minimum deviation of the profile of each blade is located at a distance from the radially inner edge of the blade that is between 40% and 100% of the height of the blade, preferably between 40% and 85% of the height of the blade;

[0015] - the deviation of the profile of each blade decreases from the radially inner edge of the blade towards the tip of the blade over at least 50% of the height of the blade, preferably over at least 70% of the height of the blade, for example over about 80% of the height of the blade;

[0016] - the deviation of the profile of each blade decreases from the radially inner edge of the blade towards the tip of the blade to a first zone of the blade, the first zone extending at a distance from the radially inner edge of the blade comprised between 45% and 85% of the height of the blade, preferably between 70% and 85% of the height of the blade;

[0017] - the deviation of the profile of each blade increases from a first region of the blade to the tip of the blade;

[0018] - the deviation of the profile of each blade is greater than 20° over at least a portion of the blade extending from the radially inner edge of the blade to a second zone of the blade, the second zone extending at a distance between 0% and 40% of the height of the blade;

[0019] - the deviation of the profile of each blade at the radially inner boundary of the blade is strictly greater than the deviation of the profile at the tip of the blade;

[0020] - the maximum deviation of the profile of each blade is located at a distance from the radially inner edge of the blade that is between 0% and 40% of the height of the blade;

[0021] - the deviation of the profile of each blade is less than 25° over a portion of the blade extending from the radial inner edge to a distance between 40% and 80% of the height of the blade;

[0022] - the deviation of the profile of each blade at the tip of the blade is between 10° and 25°;

[0023] the first region of the blade extends at a distance from the radially inner edge of the blade which is between 45% and 75% of the height of the blade, preferably between 50% and 70% of the height of the blade;

[0024] - the deviation of the profile of each blade is less than 25° over a portion of the blade extending from a first distance between 10% and 20% of the height of the blade to a second distance between 80% and 100% of the height of the blade;

[0025] - the deviation of the profile of each blade at the tip of the blade is between 25° and 35°;

[0026] - the deviation of the profile of each blade is strictly greater than 20° over the entire height of the blade;

[0027] - the deviation of the profile of each blade at the tip of the blade is greater than or equal to the deviation of the profile at the radially inner edge of the blade;

[0028] - the outer guide vanes comprise 8 to 12 blades; and / or

[0029] - The length of the chord of each blade at the tip of the blade is less than 75% of the maximum chord of the blade.

[0030] According to a second aspect, the present invention proposes an unducted thrust generation assembly for a turbine engine, the unducted thrust generation assembly comprising a propeller and an outer guide vane according to the first aspect, the propeller being rotatable relative to a casing of the turbine engine, the outer guide vane being fixedly mounted on the casing and extending downstream of the propeller.

[0031] The propeller may include ten to sixteen rotating blades. The outer guide vanes may include eight to fourteen blades.

[0032] According to a third aspect, there is provided a turbine engine comprising a casing and an unducted thrust generating assembly according to the second aspect, the propeller being rotatable relative to the casing and the outer guide vanes being rotationally fixed relative to the casing.

[0033] At least one of the propeller and the outer guide vanes has a variable pitch. Preferably, the propeller and the outer guide vanes have a variable pitch.

[0034] According to a fourth aspect, an aircraft is proposed, comprising a turbine engine according to the third aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Other characteristics, objects and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting and should be read in conjunction with the accompanying drawings, in which:

[0036] Figure 1 An example of a USF type turbine engine according to an embodiment of the invention is schematically shown;

[0037] Figure 2 is a schematic cross-sectional view (in a plane perpendicular to an axis that is radial relative to the axis of the turbine engine) of an example of a blade of an outer guide vane according to an exemplary embodiment of the invention;

[0038] Figure 3shows the deviation (δ, in degrees) of an exemplary embodiment of a blade of an outer guide vane according to the invention as a function of the distance (%h) from the radially inner border of the blade; and

[0039] Figure 4 An aircraft comprising two turbine engines according to one embodiment of the invention is schematically shown.

[0040] In all the figures, similar elements have the same reference numerals. DETAILED DESCRIPTION

[0041] The turbine engine 1, in particular of an aircraft 2, has a main direction extending along a longitudinal axis X and generally comprises, from upstream to downstream in the direction of the airflow, a thrust generating assembly 3 and a gas generator. The gas generator may comprise a compression section (which may comprise a low-pressure compressor and a high-pressure compressor), a combustion chamber, a turbine section (which may comprise a high-pressure turbine and a low-pressure turbine) and an exhaust casing.

[0042] The thrust generating assembly 3 is preferably unducted, that is to say it is not surrounded by an external nacelle or fairing of the turbine engine 1. The thrust generating assembly 3 comprises a propeller 4 (rotor) mounted rotatably about an axis X and an outer guide vane arrangement 5 (stator), coaxial with the propeller 4 and mounted immediately downstream of the propeller at the outlet of the propeller 4. In one embodiment, the propeller 4 is a variable pitch propeller and comprises a pitch changing mechanism configured to pivot each blade of the propeller 4 about a respective pivot axis, which is radial with respect to the axis of rotation X of the propeller 4.

[0043] The outer guide vane device 5 has the function of axially straightening the air flow F rotated by the propeller 4. In fact, the propeller 4 generates a gyration of the flow downstream, wherein the gyration is the tangential velocity component of the flow (in a cylindrical reference frame in which the main propeller axis X corresponds to the engine axis X). This component is zero upstream of the propeller 4 and it appears due to the rotational drive of the propeller 4 on the flow. Since any non-zero tangential velocity component has the effect of reducing the thrust generated by the engine and increasing the losses of thrust, the (static) outer guide vane device 5 has the function of counteracting this component and redirecting it in the axial direction.

[0044] The propeller 4 may comprise ten to sixteen blades 6. The outer guide vane arrangement 5 may comprise eight to fourteen blades 7. The blades 7 of the outer guide vane arrangement 5 and the blades of the propeller 4 may be made of any suitable material, for example a metal or a composite material comprising a fiber reinforcement densified by a matrix, typically a polymer resin.

[0045] In the present application, the axial direction corresponds to the direction of the axis X, and the radial direction is a direction perpendicular to and passing through the axis X. Furthermore, the circumferential direction corresponds to a direction perpendicular to but not passing through the axis X. Unless otherwise stated, inner (inner) and outer (outer) are used with reference to radial directions, respectively, such that an inner part or inner surface of an element is closer to the axis X than an outer part or outer surface of the same element.

[0046] The outer guide vane device 5 comprises stator vanes 7 fixedly mounted on an outer casing 8 (usually a casing surrounding the generator) of the turbine engine 1. In the case of an unducted propulsion unit 3, the outer casing 8 corresponds to a nacelle surrounding the generator. To this end, each vane 7 has a root mounted in the outer casing 8 and an airfoil 9 with an aerodynamic profile suitable for being arranged in the air flow F when the turbine engine 1 is in operation to straighten the air flow F at the outlet of the propeller 4.

[0047] The vane 7 has a radially inner boundary 10 corresponding to the intersection between the nacelle 8 and the vane 7 and a tip 11 at the free end of the vane corresponding to the radially outer boundary of the vane 7. The radially outer boundary of the vane 7 thus radially delimits the flow through the outer guide vane arrangement 5.

[0048] The vane 7 also has a pressure surface 12, a suction surface 13, a leading edge 14 and a trailing edge 15. In a manner known per se, the leading edge 14 is configured to extend opposite the flow of gas entering the outer guide vane device 5. In normal operation outside the reverse thrust mode, the leading edge corresponds to a front portion with an aerodynamic profile, which faces the air flow F and divides this air flow into a pressure surface flow 12 and a suction surface flow 13. The trailing edge 15 corresponds to a rear portion with an aerodynamic profile, where the pressure surface flow and the suction surface flow meet.

[0049] In order to improve the aerodynamic performance of the turbine engine 1 and reduce the noise generated by the thrust generating assembly 3, the load of the tip 11 of the blade 7 should be appropriately released. In fact, therefore, the recovery of the force is maximized in the area where the outer guide vane device 5 has a higher solidity, usually at the radial inner boundary 10 of the blade 7. The load of the tip 11 of the blade 7 is small, which also makes it possible to reduce the noise generated by the vortex at the blade tip 7, the noise generated by the wake interaction of the propeller 4-outer guide vane device 5, and the inherent noise of the propeller 4 and the outer guide vane device 5 at the blade tip 7. Therefore, the aeroacoustic performance of the outer guide vane device 5 is improved by reducing the aerodynamic forces at the blade tip, while improving the distribution of mechanical stresses in the blade 7.

[0050] In this regard, a number of structural parameters of the blades 7 of the outer guide vane device 5 can be taken into account, including the dihedral angle and the deviation δ of the profile of each blade 7. The consideration of the dihedral angle is described in more detail in document FR3124832 in the name of the applicant. The deviation δ of the profile of the blade 7 corresponds to the absolute value of the difference between the tangent line of the skeleton 16 at the leading edge 14 of the blade 7 and the tangent line of the skeleton 16 at the trailing edge 15 of the blade 7. The skeleton 16 here refers to an imaginary line extending from the leading edge 14 to the trailing edge 15 of the blade 7, which is equidistant between the pressure surface 12 and the suction surface 13 of the blade 7.

[0051] In the turbine engine 1, each vane 7 of the outer guide vane device 5 is shaped so that the deviation δ of the profile of the vane 7 is between 20° and 45°, preferably between 25° and 35°, at the radially inner border 10 of the vane 7, and so that the deviation of the profile of the vane is between 10° and 40° at the tip 11 of the vane 7. This configuration of the vane 7 in particular maximizes the deviation of the air flow F passing through the outer guide vane device 5 at the base of the vane (i.e. in the region extending close to the radially inner border 10 of the vane 7) rather than at the tip 11 (which relieves the tip 11 of the vane 7 from load).

[0052] Various profile shapes of the blades 7 can be considered, such as Figure 3 It should be noted that for reasons of manufacturing simplicity, preferably each vane 7 of the outer guide vane arrangement 5 has substantially the same contour shape (within manufacturing tolerances). However, this is not restrictive, as the vanes 7 may have different contours within the same outer guide vane arrangement 5 .

[0053] Whatever the shape considered, advantageously the minimum deviation δ of the blade 7 最小 Located at a distance ( Figure 3 %h in the figure, this distance is between 40% and 100% of the height h of the blade 7, that is, the minimum deviation of the blade is located in the portion of the blade 7 adjacent to the tip 11. The height h of the blade 7 is here the distance between the radial inner boundary 10 of the blade 7 and the tip 11 (measured along the radial axis of the blade 7 passing through the tip 11). For example, the minimum deviation of the profile δ 最小 can be located at a distance equal to about 80% (accurate to within 5%) of the height h of the blade 7 ( Figure 3 However, this is not restrictive, since the minimum deviation δ of the blade 7 最小 It can also be located at a distance from the radial inner edge 10 of the blade 7 that is between 40% and 85% of the height h of the blade 7, that is, the minimum deviation of the blade is located in the middle part of the blade 7. For example, the minimum deviation of the profile δ 最小can be located at a distance equal to about 65% (accurate to within 5%) of the height h of the blade 7 ( Figure 3 ), or at a distance equal to about 55% (accurate to within 5%) of the height h of the blade 7 ( Figure 3 ).

[0054] Furthermore, advantageously, the deviation δ of the profile of each blade 7 decreases from the radially inner border 10 of the blade 7 towards the tip 11 of the blade 7 over at least 50% of the height h of the blade 7, preferably over at least 70% of the height h of the blade 7, for example over about 80% of the height h of the blade 7. Preferably, the deviation decreases from the radially inner border 10 of the blade 7 towards the tip 11 of the blade 7 to a region of the blade 7 extending at a distance from the radially inner border 10 of the blade 7 between 45% of the height h of the blade 7 and 85% of the height h of the blade 7, for example between 70% of the height h of the blade 7 and 85% of the height h of the blade 7. In some embodiments ( Figure 3 ), the deviation decreases from the radial inner boundary 10 of the blade 7 towards the tip 11 of the blade 7 to a region of the blade 7 which extends at a distance from the radial inner boundary 10 of the blade 7 which is between 45% of the height h of the blade 7 and 75% of the height h of the blade 7, for example between 50% of the height h of the blade 7 and 20% of the height h of the blade 7. If appropriate, the deviation can then increase up to the tip 11 of the blade 7. Thus, the deviation δ decreases from the radial inner boundary 10 of the blade over a portion or even a large portion of the height h of the blade 7. Then, the deviation increases.

[0055] Furthermore, advantageously, the deviation δ of the profile of each vane 7 is greater than 15°, preferably greater than 20°, at least at the bottom of the airfoil 9, for example on a portion of the vane 7 extending from the radially inner border 10 of the vane 7 to the lower region of the vane 7, which extends at a distance between 0% and 40% of the height h of the vane 7. In some embodiments, the deviation δ of the profile of each vane 7 is also greater than 20° at the top of the airfoil 9, for example on a portion of the vane extending from the lower region of the vane 7 to the tip 11 of the vane 7, which extends at a distance between 70% and 80% of the height h of the vane 7 ( Figure 3 In appropriate cases, the deviation δ of the profile of each blade 7 can even be strictly greater than 20° over the entire height h of the blade 7 ( Figure 3 ).

[0056] In some embodiments, the deviation δ of the profile of each vane 7 at the radial inner boundary 10 of the vane 7 is strictly greater than the deviation δ of the profile at the tip 11 of the vane 7, so as to maximize the deviation of the air flow F at the bottom of the airfoil 9 ( Figure 3 ). Where appropriate, advantageously, the dihedral angle of the blade 7 is inclined towards the pressure surface 12. Furthermore, a smaller deviation at the head makes it possible to obtain an outer guide vane device 5, the chord of the blade 7 of which is smaller at the tip (i.e. at the tip 11 of the blade) than at the root (i.e. at the radially inner boundary 10), which makes it possible to further reduce losses. Furthermore, preferably, the length of the chord at the head of each blade 7 is smaller than 75% of the maximum chord of the blade 7 over the height of the blade 7. However, this is not restrictive, since the deviation δ of the profile of each blade 7 at the tip 11 of the blade 7 may alternatively be greater than or equal to the deviation δ of the profile at the radially inner boundary 10 of the blade 7. Where appropriate, the dihedral angle is neutral, or even inclined towards the suction surface 13.

[0057] Furthermore, advantageously, the maximum deviation δ of the profile of each blade 7 最大 is located at a distance from the radial inner edge 10 of the blade 7 which is between 0% and 40% of the height h of the blade 7. For example, the maximum deviation of the profile δ 最大 can be located at the radial inner boundary 10 ( Figure 3 In some cases, the maximum deviation of the profile δ 最大 In the first third of the height h of the blade 7, the minimum deviation δ 最小 Located in the rear third ( Figure 3 The solid curve in .

[0058] Furthermore, advantageously, the deviation δ of the profile of each vane 7 is less than 25° at the top of the airfoil 9, for example over a portion of the vane 7 extending from the radially inner border 10 to a distance comprised between 40% and 80% of the height h of the vane 7 ( Figure 3 Alternatively, the deviation δ of the profile of each blade 7 may be less than 25° over a portion of the blade 7 extending from a first distance between 10% and 20% of the height of the blade 7 to a second distance between 80% and 100% of the height of the blade 7 ( Figure 3 The dashed dot curve and dashed line curve in the figure).

[0059] Figure 3 The solid curve shown corresponds to the deviation δ of the profile of the blade 7, wherein the maximum deviation δ 最大is about 25° and is located at the radial inner boundary 10 of the blade 7. Furthermore, the deviation δ decreases from the radial inner boundary 10 of the blade 7 over a distance equal to 75% to 80% of the height h of the blade 7, wherein the deviation reaches a minimum value of about 17°. The reduction of the deviation δ is continuous over the entire height h of the blade 7 until the minimum value δ of the deviation is reached. 最小 This deviation then increases until the tip 11 of the blade 7 , where it is between 10° and 25°, preferably substantially equal to 18°.

[0060] Figure 3 The dashed curve shown in turn corresponds to a deviation δ of the profile of the blade 7, wherein the maximum deviation δ is greater than 30° at most and is preferably substantially equal to 32°, which is located at the radially inner boundary 10 of the blade 7. Furthermore, the deviation δ decreases starting from the radially inner boundary 10 of the blade 7 over a distance equal to 60% to 65% of the height h of the blade 7, wherein the deviation reaches a minimum value of about 18°. The reduction of the deviation δ is continuous over the entire height h of the blade 7 until a minimum value δ of the deviation is reached. 最小 This deviation then increases until the tip 11 of the blade 7 , where it is between 25° and 30°, preferably substantially equal to 27°.

[0061] for Figure 3 The dashed curve shown corresponds to the deviation δ of the profile of the blade 7, wherein the maximum deviation δ 最大 30° and preferably substantially equal to 32°, the maximum deviation being located at the radially inner edge 10 of the blade 7, but also at the tip 11 of the blade 7. Furthermore, the deviation δ decreases starting from the radially inner edge 10 of the blade 7 over a distance equal to 55% to 60% of the height h of the blade 7, wherein the deviation reaches a minimum value of about 21°. The reduction of the deviation δ is continuous over the entire height h of the blade 7 until a minimum value δ of the deviation is reached. 最小 The deviation then increases until the tip 11 of the blade 7 .

[0062] It should be noted that the height h of the vanes 7 of the outer guide vane device 5 can be substantially equal to the height of the blades 6 of the propeller 4, wherein the height of the blades 6 of the propeller 4 corresponds to the distance between the radial inner boundary 10 of the blade 6 and the tip of the blade 6 (measured along the pivot axis of the blade 6 or, where appropriate, along an axis that is radial to the axis X passing through the tip of the blade).

[0063] Alternatively, the height h of the vanes 7 of the outer guide vane arrangement 5 can be smaller than the height of the blades 6 of the propeller 4 .

Claims

1. An outer guide vane arrangement (5) for an unducted thrust generating assembly (3) of a turbine engine (1), the outer guide vane arrangement comprising a plurality of vanes (7), each vane having: - a tip (11) and a radial inner boundary (10) corresponding to the intersection between the casing (8) of the turbine engine (1) and the blade (7); - a skeleton (16) corresponding to an imaginary line extending from the leading edge (14) to the trailing edge (15) of the blade (7), said imaginary line being equidistant between the pressure surface (12) and the suction surface (13) of the blade (7); as well as - a deviation (δ) of the profile, the deviation corresponding to the absolute value of the difference between a tangent to the skeleton (16) at the leading edge (14) of the blade and a tangent to the skeleton (16) at the trailing edge (15) of the blade (7), the deviation being between 20° and 45° at the radial inner boundary (10) of the blade (7) and between 10° and 40° at the tip (11) of the blade (7).

2. The outer guide vane device (5) according to claim 1, wherein: The deviation (δ) of the profile of each blade (7) at the radial inner boundary (10) of the blade (7) is between 25° and 35°.

3. The outer guide vane device (5) according to claim 1 or 2, wherein: The minimum deviation (δ) of the profile of each blade (7) 最小 ) is located at a distance from the radial inner boundary (10) of the blade (7), the distance being between 40% and 100% of the height of the blade (7), preferably between 40% and 85% of the height of the blade.

4. The outer guide vane device (5) according to any one of claims 1 to 3, wherein: The deviation (δ) of the profile of each blade (7) decreases from the radial inner boundary (10) of the blade (7) towards the tip (11) of the blade (7) over at least 50% of the height of the blade (7), preferably over at least 70% of the height of the blade (7), for example over about 80% of the height of the blade (7).

5. The outer guide vane device (5) according to claim 4, wherein: The deviation (δ) of the profile of each blade (7) decreases from the radial inner border (10) of the blade (7) towards the tip (11) of the blade (7) to a first region of the blade (7), the first region extending at a distance from the radial inner border (10) of the blade (7) being between 45% and 85% of the height of the blade (7), preferably between 70% and 85% of the height of the blade (7).

6. The outer guide vane device (5) according to claim 5, wherein: The deviation (δ) of the profile of each blade (7) increases from the first region of the blade (7) to the tip (11) of the blade (7).

7. The outer guide vane device (5) according to any one of claims 1 to 6, wherein: The deviation (δ) of the profile of each blade (7) is greater than 20° over at least a portion of the blade (7) extending from the radial inner boundary (10) of the blade (7) to a second region of the blade (7), the second region extending at a distance between 0% and 40% of the height of the blade (7).

8. The outer guide vane device (5) according to any one of claims 1 to 7, wherein: The deviation (δ) of the profile of each blade (7) at the radially inner boundary (10) of the blade (7) is strictly greater than the deviation (δ) of the profile at the tip (11) of the blade (7).

9. The outer guide vane device (5) according to any one of claims 1 to 8, wherein: The maximum deviation (δ) of the profile of each blade (7) 最大 ) is located at a distance below the radial inner boundary (10) of the blade (7), the distance being between 0% and 40% of the height of the blade (7).

10. The outer guide vane arrangement (5) according to any one of claims 1 to 9, wherein: The deviation (δ) of the profile of each blade (7) is less than 25° over a portion of the blade (7) extending from the radial inner boundary (10) to a distance between 40% and 80% of the height of the blade (7).

11. The outer guide vane arrangement (5) according to any one of claims 1 to 10, wherein: The deviation (δ) of the profile of each blade (7) at the tip (11) of the blade (7) is between 10° and 25°.

12. The outer guide vane device (5) according to claim 5 or 6, wherein: The first region of the blade (7) extends at a distance below the radial inner boundary (10) of the blade (7), the distance being between 45% and 75% of the height of the blade (7), preferably between 50% and 70% of the height of the blade (7).

13. The outer guide vane arrangement (5) according to any one of claims 1 to 7, wherein: The deviation (δ) of the profile of each blade (7) is less than 25° over a portion of the blade (7) extending from a first distance between 10% and 20% of the height of the blade (7) to a second distance between 80% and 100% of the height of the blade (7).

14. The outer guide vane arrangement (5) according to any one of claims 1 to 7 and 13, wherein: The deviation (δ) of the profile of each blade (7) at the tip (11) of the blade (7) is between 25° and 35°.

15. The outer guide vane arrangement (5) according to any one of claims 1 to 7, 13 and 14, wherein: The deviation (δ) of the profile of each blade (7) is strictly greater than 20° over the entire height of the blade (7).

16. The outer guide vane arrangement (5) according to any one of claims 1 to 7 and 13 to 15, wherein: The deviation (δ) of the profile of each blade (7) at the tip (11) of the blade (7) is greater than or equal to the deviation (δ) of the profile at the radial inner boundary (10) of the blade (7).

17. The outer guide vane arrangement (5) according to any one of claims 1 to 16, comprising 8 to 12 vanes (7).

18. The outer guide vane arrangement (5) according to any one of claims 1 to 17, wherein: The length of the chord of each blade (7) at the tip (11) of the blade (7) is less than 75% of the maximum chord of the blade (7).

19. A ductless thrust generating assembly (3) for a turbine engine (1), comprising a propeller (4) and an outer guide vane device (5) according to any one of claims 1 to 18, wherein the propeller is rotatable relative to a casing (8) of the turbine engine (1), and the outer guide vane device is fixedly mounted on the casing (8) and extends downstream of the propeller (4).

20. The assembly of claim 19, wherein: The propeller (4) comprises ten to sixteen rotating blades (6).

21. A turbine engine (1) comprising a casing (8) and an unducted thrust generating assembly (3) according to claim 19 or 20, the propeller (4) being rotatable relative to the casing (8), and the outer guide vane device (5) being rotationally fixed relative to the casing (8) downstream of the propeller (4).

22. Turbine engine (1) according to claim 21, wherein: At least one of the propeller (4) and the outer guide vane arrangement (5) has a variable pitch.

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