Guide vane for attachment to a stator shroud of a gas turbine engine, gas turbine engine stator assembly and gas turbine engine

Abstract

The invention relates to a guide vane (33B) for attachment to a stator shroud of a gas turbine engine, comprising: - a profiled part (36B) intended to extend in a gas flow in order to guide the gas flow, the profiled part (36B) having a pressure-side surface (43B) and a suction-side surface (44B), and - a platform (34B) having a guide surface (45B) from which the profiled part (36B) extends, a first lateral surface (46B) and a second lateral surface (47B), the second lateral surface (47B) being able to be arranged facing a first lateral surface (46A) of an identical adjacent guide vane (33A), forming a raised portion which prevents a parasitic transverse flow of the gas flow, while creating a depression which at least partially compensates for the obstruction of the gas flow by the raised portion.

Description

[0001] DESCRIPTION

[0002] TITLE :

[0003] GUIDE VANE FOR ATTACHMENT TO A STATOR SHROUD OF A GAS TURBINE ENGINE, TURBINE ENGINE STATOR ASSEMBLY

[0004] GAS AND GAS TURBINE ENGINE

[0005] FIELD OF THE INVENTION

[0006] The invention relates to a guide vane intended to be fixed on a shroud of a stator of a gas turbine engine. The invention also relates to an assembly comprising a set of guide vanes and a gas turbine engine comprising such an assembly.

[0007] STATE OF THE ART

[0008] Gas turbine engines typically consist of a fan module, a compressor module, a combustor, and a turbine module.

[0009] The blower module, the compressor module and the turbine module each include rotating parts (or "rotor") and stationary parts (or "stator").

[0010] For example, the fan module includes a fan housing and a fan rotor adapted to be rotated relative to the fan housing. The fan rotor includes one or more rows of moving blades. Rotation of the fan rotor compresses air, which is expelled rearward to produce a portion of the engine's thrust.

[0011] In addition, the fan module typically includes a set of outlet guide vanes (also called "Outlet Guide Vanes" or "OGVs") located downstream of the fan rotor and acting as a rectifier. This set of fixed vanes serves to straighten and regulate the airflow downstream of the fan rotor to optimize engine thrust. This set of fixed vanes also acts as a noise reducer.

[0012] The airflow passing through the set of fixed blades generally flows between the fixed blades in an upstream-downstream direction. However, secondary aerodynamic flows may appear near the roots of the fixed blades. Indeed, for each pair of blades facing each other, a pressure gradient between the pressure surface (intrados surface) of a blade and the depression surface (extrados surface) of an adjacent blade generates a parasitic transverse flow which transports the air from the intrados surface to the extrados surface of the adjacent blade.

[0013] Furthermore, at the blade tip, i.e. at the junction between the fixed blade and the inner shroud of the casing or at the junction between the fixed blade and the outer shroud of the casing, corner separation and a corner vortex can occur. This separation generates pressure losses as well as aerodynamic blockage. Such aerodynamic blockage is problematic in terms of operability. For high incidences of the air flow arriving at the fixed blades, i.e. when the direction of air flow upstream of the fixed blades makes a significant angle with a direction of the leading edge of the blades, this corner separation increases to the point of causing a separation of the boundary layer on the aerodynamic part of the blade which can no longer ensure the deflection of the flow.

[0014] Other engine vane assemblies are affected by this phenomenon, notably in the stator vane assemblies facing the moving vane assemblies in compressors or in the nozzle vane assemblies facing the moving vane assemblies in turbines.

[0015] To overcome this problem, one solution is to insert a fin between two adjacent fixed blades, the function of which is to block the transverse flow of gas flowing from the intrados surface of one fixed blade to the extrados surface of the adjacent fixed blade. Document FR 3 106 614 describes an example of a fin.

[0016] However, a disadvantage of this solution is that it requires the manufacturing and assembly of additional parts (fins).

[0017] It would also be possible to machine a fin directly into a blade platform. However, this would complicate blade manufacturing.

[0018] SUMMARY OF THE INVENTION An aim of the invention is to propose a solution for blocking parasitic flows in fixed blade assemblies, while limiting obstruction of the gas flow path.

[0019] This problem is solved within the framework of the present invention thanks to a guide vane intended to be fixed on a stator shell of a gas turbine engine, comprising:

[0020] - a profiled portion intended to extend into a gas flow to guide the gas flow, the profiled portion having an intrados surface and an extrados surface, and

[0021] - a platform having a guide surface from which the profiled portion extends, a first lateral surface and a second lateral surface, the second lateral surface being adapted to be arranged opposite a first lateral surface of an identical adjacent guide vane, such that the platform of the guide vane delimits with the platform of the adjacent guide vane a flow path for the gas flow flowing between the profiled portion of the guide vane and the profiled portion of the adjacent guide vane, the guide surface comprising a first guide surface portion extending from the intrados surface of the profiled portion to the first lateral surface and a second guide surface portion extending from the extrados surface of the profiled portion to the second lateral surface,wherein a first joining line is formed at the intersection between the first guide surface portion and the first side surface, a second joining line is formed at the intersection between the second guide surface portion and the second side surface, a third joining line is formed at the intersection between the first guide surface portion and the pressure surface, and a fourth joining line is formed at the intersection between the second guide surface portion and the suction surface, the first guide surface portion and the second guide surface portion being configured such that when the guide vane is attached to the shroud, the first joining line has a first radius measured from the central axis of the shroud, in a plane transverse to the central axis, the second joining line has a second radius measured from the central axis,in the plane transverse to the central axis, the second radius being greater than the first radius, the third joining line has a third radius measured from the central axis, in the plane transverse to the central axis, and the fourth joining line has a fourth radius measured from the central axis in the plane transverse to the central axis, the fourth radius being less than or equal to the third radius.,

[0022] The second radius greater than the first radius makes it possible to create a step (or a step) between the second guide surface of the guide vane and the first guide surface of the adjacent guide vane, preventing parasitic circulation of a portion of the gas flow from the intrados surface of the guide vane to the extrados surface of the guide vane.

[0023] Thus, the second guide surface has an elevation relative to the first guide surface.

[0024] However, the fourth ray is kept less than or equal to the third ray. This allows for the generation of a depression that compensates for the obstruction of the vein generated by the presence of the elevation.

[0025] The proposed guide vane may further have the following characteristics:

[0026] - the first ray is equal to the third ray, and the fourth ray is less than the third ray;

[0027] - a difference between the second ray and the first ray is equal to a difference between the third ray and the fourth ray;

[0028] - the fourth ray is equal to the third ray;

[0029] - a difference between the second ray and the fourth ray is equal to a difference between the third ray and the first ray;

[0030] - the profiled portion has a leading edge and a trailing edge, and the platform has a first transverse surface extending in a first transverse plane located upstream of the leading edge, and a second transverse surface extending in a second transverse plane located downstream of the trailing edge, the first joining line extending from the first transverse plane to the second transverse plane and the second joining line extending from the first transverse plane to the second transverse plane, and in which a difference between the second radius and the first radius has a zero value from the first transverse plane to a third transverse plane located between the first transverse plane and the second transverse plane, and then which increases continuously from a zero value in the third transverse plane,up to a maximum value in a fourth transverse plane located between the third transverse plane and the second transverse plane, and which decreases continuously from the maximum value in the fourth transverse plane to a zero value in the second transverse plane;,

[0031] - the third transverse plane is defined as a transverse plane passing through a point on the fourth junction line where the curvature of the fourth junction line is maximum;

[0032] - the first junction line has a first radius having a constant value from the first transverse plane to the second transverse plane;

[0033] - the first junction line has a first radius having a constant value from the first transverse plane to the third transverse plane, then which decreases continuously from the third transverse plane to the fourth transverse plane, and which increases continuously from the fourth transverse plane to the second transverse plane;

[0034] - the second junction line has a second radius having a constant value from the first transverse plane to the third transverse plane, then which increases continuously from the third transverse plane to the fourth transverse plane, and which decreases continuously from the fourth transverse plane to the second transverse plane;

[0035] - an axial distance between the third transverse plane and the second transverse plane is between 10% and 40% of a chord length of the profiled part, the chord length of the profiled part being defined as a distance between a point of intersection between the leading edge and the guide surface of the platform and a point of intersection between the trailing edge and the guide surface of the platform.

[0036] The invention further relates to a gas turbine engine stator assembly, comprising:

[0037] - a ferrule with a central axis,

[0038] - a guide vane assembly comprising a plurality of guide vanes, each guide vane comprising a platform having a guide surface and a profiled portion extending radially from the guide surface of the platform, the profiled portion having a pressure surface and an extrados surface, and the platform having a first lateral surface and a second lateral surface, and the guide surface of the platform comprising a first guide surface portion extending from the pressure surface of the profiled portion to the first lateral surface and a second guide surface portion extending from the extrados surface of the profiled portion to the second lateral surface,the guide vanes being fixed to the shroud such that the second lateral surface of each guide vane is arranged opposite a first lateral surface of an adjacent guide vane of the set of guide vanes, and the first guide surface portions and the second guide surface portions of the platforms define a flow path for a gas stream flowing between the profiled portions of the guide vanes, wherein each guide vane has a first junction line formed at the intersection between the first guide surface portion and the first lateral surface, a second junction line formed at the intersection between the second guide surface portion and the second lateral surface, a third junction line formed at the intersection between the first guide surface portion and the intrados surface,and a fourth junction line formed at the intersection between the second guide surface portion and the suction surface, and wherein the first junction line has a first radius measured from the central axis in a plane transverse to the central axis, the second junction line has a second radius measured from the central axis, in the plane transverse to the central axis, the second radius being greater than the first radius, such that a portion of the second lateral surface extends into the gas flow forming a wall preventing parasitic circulation of a portion of the gas flow from the suction surface of a guide vane to the suction surface of an adjacent guide vane, the third junction line has a third radius measured from the central axis in the plane transverse to the central axis,and the fourth joining line has a fourth radius measured from the central axis in the plane transverse to the central axis, the fourth radius being less than or equal to the third radius.,

[0039] In such an assembly, each guide vane may have one of the characteristics defined above.

[0040] The guide vanes of the guide vane set may be identical to each other.

[0041] In one possible embodiment, the shroud is an inner stator shroud and the guide surfaces of the guide vane platforms form an inner flow path wall of the gas stream. In another possible embodiment, the shroud is an outer stator shroud and the guide surfaces of the guide vane platforms form an outer flow path wall of the gas stream.

[0042] The assembly may be a compressor stator rectifier assembly or a turbine stator rectifier assembly or a fan rectifier assembly.

[0043] The invention further relates to a gas turbine engine comprising an assembly as defined above.

[0044] PRESENTATION OF THE DRAWINGS

[0045] Other characteristics and advantages will emerge from the following description, which is purely illustrative and not limiting, and must be read in conjunction with the appended figures, among which:

[0046] - figure 1 shows, schematically, in longitudinal section, a gas turbine engine,

[0047] - Figure 2 schematically represents a stator rectifier assembly of a gas turbine engine,

[0048] - figure 3 schematically represents guide vanes assembled on a stator shell,

[0049] - figure 4 schematically represents an assembly of two guide vanes in accordance with a first embodiment of the invention,

[0050] - figure 5 schematically represents an assembly of two guide vanes in accordance with a second embodiment of the invention,

[0051] - figure 6 shows, schematically, in top view, an assembly of two guide vanes,

[0052] - figures 7A to 7C, schematically represent the two guide vanes conforming to the first embodiment, in three different transverse section planes,

[0053] - figure 7D schematically represents a view of the extrados side of one of the guide vanes of the assembly,

[0054] - figure 7E schematically represents a view of the intrados side of the other of the guide vanes of the assembly, - figures 8A to 8C schematically represent the two guide vanes conforming to the second embodiment, in three different transverse section planes,

[0055] - figure 8D schematically represents a view of the extrados side of one of the guide vanes of the assembly,

[0056] - Figure 8E schematically represents a view of the intrados side of the other of the guide vanes of the assembly.

[0057] DETAILED DESCRIPTION OF AN EMBODIMENT

[0058] In Figure 1, the gas turbine engine 1 shown is a two-spool, two-flow gas turbine engine.

[0059] The gas turbine engine 1 has a longitudinal axis A.

[0060] The gas turbine engine 1 comprises a nacelle 2, a fan module 3, a compressor module 4, a combustion chamber 5, and a turbine module 6.

[0061] In the example illustrated in Figure 1, the fan module 3 comprises a fan casing 7 mounted fixedly relative to the nacelle, a fan 8 capable of being driven in rotation relative to the fan casing 7 and fixed outlet vanes 9 (also called “Outlet Guide Vane” or “OGV” in English) mounted fixedly on the fan casing 7 and having the function of straightening the secondary air flow which flows out of the fan 8.

[0062] In the example illustrated in Figure 1, the compressor module 4 comprises a low pressure compressor 10 and a high pressure compressor 11.

[0063] In addition, the turbine module 6 comprises a high pressure turbine 12 and a low pressure turbine 13.

[0064] The gas turbine engine 1 comprises a low pressure shaft 14 connecting the low pressure turbine 13 to the low pressure compressor 10 and to the fan 8, and a high pressure shaft 15 connecting the high pressure turbine 12 to the high pressure compressor 11. The high pressure shaft 15 is coaxial with the low pressure shaft 14 and extends around the low pressure shaft 14. The high pressure shaft 15 and the low pressure shaft 14 are rotatably mounted relative to the nacelle 2, around the longitudinal axis A of the engine.

[0065] Blower 8, low pressure compressor 10, low pressure turbine

[0066] 13, and the low pressure shaft 14 together form the low pressure body of the engine 1. The low pressure turbine 13 is capable of driving the low pressure compressor 10 and the blower 8 in rotation via the low pressure shaft 14.

[0067] More specifically, the low-pressure compressor 10 comprises a low-pressure compressor casing 16, fixedly mounted relative to the nacelle 2, a low-pressure compressor rotor 17, and a low-pressure compressor stator 18. The low-pressure compressor rotor 17 is capable of being driven in rotation relative to the low-pressure compressor stator 18, around the longitudinal axis A of the engine 1. The low-pressure compressor rotor 17 comprises moving blades. The low-pressure compressor stator 18 comprises fixed blades (also called “guide blades” or “straightener blades”) which are fixedly mounted on the low-pressure compressor casing 16 by being interposed between the moving blades. These fixed blades have the function of guiding the primary air flow through the low-pressure compressor 10.

[0068] Likewise, the low pressure turbine 13 comprises a low pressure turbine casing 19, mounted fixedly relative to the nacelle 2, a low pressure turbine rotor

[0069] 20, and a low pressure turbine stator 21. The low pressure turbine rotor 20 is adapted to be rotated relative to the low pressure turbine stator

[0070] 21, around the longitudinal axis A of the engine 1. The low pressure turbine rotor 20 comprises moving blades. The low pressure turbine stator 21 comprises fixed blades which are fixedly mounted on the casing of the low pressure turbine 19 by being interposed between the moving blades. These fixed blades have the function of guiding the primary air flow through the low pressure turbine 13.

[0071] The low pressure turbine rotor 20 is connected to the low pressure compressor rotor 17 via the low pressure shaft 14. Thus, when the engine 1 is in operation, rotation of the low pressure turbine rotor 20 causes rotation of the low pressure compressor rotor 17.

[0072] The high-pressure compressor 11, the high-pressure turbine 12 and the high-pressure shaft 15 together form the high-pressure body of the engine 1. The high-pressure turbine 12 is capable of driving the high-pressure compressor 11 in rotation by means of the high-pressure shaft 15.

[0073] More specifically, the high-pressure compressor 11 comprises a high-pressure compressor casing 22, fixedly mounted relative to the nacelle 2, a high-pressure compressor rotor 23, and a high-pressure compressor stator 24. The high-pressure compressor rotor 23 is capable of being driven in rotation relative to the high-pressure compressor stator 24, around the longitudinal axis A of the engine 1. The high-pressure compressor rotor 23 comprises moving blades. The high-pressure compressor stator 24 comprises fixed blades (also called “guide blades” or “straightener blades”) which are fixedly mounted on the casing 22 of the high-pressure compressor by being interposed between the moving blades. These fixed blades have the function of guiding the primary air flow through the high-pressure compressor 11.

[0074] Similarly, the high-pressure turbine 12 comprises a high-pressure turbine casing 25, mounted fixedly relative to the nacelle 2, a high-pressure turbine rotor 26, and a high-pressure turbine stator 27. The high-pressure turbine rotor 26 is capable of being driven in rotation relative to the high-pressure turbine stator 27, around the longitudinal axis A of the engine 1. The high-pressure turbine rotor 26 comprises moving blades. The high-pressure turbine stator 27 comprises fixed blades which are mounted fixedly on the casing 25 of the high-pressure turbine by being interposed between the moving blades. These fixed blades have the function of guiding the primary air flow through the high-pressure turbine 12.

[0075] The high pressure turbine rotor 26 is connected to the high pressure compressor rotor 23 via the high pressure shaft 15. Thus, when the engine 1 is in operation, the rotation of the high pressure turbine rotor 26 causes a rotation of the high pressure compressor rotor 23.

[0076] The fixed outlet vanes 9 of the fan module 3, the fixed stator vanes 18 of the low pressure compressor 10, the fixed stator vanes of the high pressure compressor 24, the fixed stator vanes of the high pressure turbine 27 and the fixed stator vanes of the low pressure turbine 21 are examples of guide vanes.

[0077] When the engine 1 is in operation, the blower 8 and the low pressure compressor 10 are driven in rotation by the low pressure turbine 13. Similarly, the high pressure compressor 11 is driven in rotation by the high pressure turbine 12.

[0078] Air is drawn in by the fan 8. The air drawn in by the fan 8 is divided into a primary air flow and a secondary air flow, which flow from upstream to downstream of the gas turbine engine 1.

[0079] The primary air flow flows from upstream to downstream of the gas turbine engine 1 in a primary vein, passing successively through the low-pressure compressor 10, the high-pressure compressor 11, the combustion chamber 5 where it is mixed with fuel to serve as an oxidizer, the high-pressure turbine 12 and the low-pressure turbine 13. The passage of the primary air flow through the high-pressure turbine 12 and the low-pressure turbine 13 causes rotation of the rotors 26 and 29 of the turbines which in turn drive rotation of the rotors 23 and 17 of the high-pressure and low-pressure compressors, as well as the fan 8 via the high-pressure shaft 15 and the low-pressure shaft 14. The primary air flow escapes from the engine 1 through an exhaust casing 28, located downstream of the low-pressure turbine casing 19.

[0080] The secondary airflow (also called "bypass airflow") flows from upstream to downstream of the gas turbine engine 1 in a secondary vein. This secondary airflow does not pass into the combustion chamber 5 and does not drive the turbines 12 and 13. The secondary airflow serves both to cool the periphery of the engine body and to generate the majority of the thrust provided by the gas turbine engine. The secondary airflow flows through the fixed blades 9 mounted on the fan casing 7, downstream of the fan 8.

[0081] Figure 2 schematically illustrates a stator rectifier assembly 30 of a gas turbine engine 1. In the example illustrated in Figure 2, the assembly 30 is a fan rectifier assembly. However, it could be a compressor stator rectifier assembly or a turbine stator rectifier assembly.

[0082] The assembly 30 comprises an inner shroud 31, an outer shroud 32, extending around the inner shroud 31, and a series of guide vanes 33.

[0083] The inner shell 31 has an annular shape having a central axis. Similarly, the outer shell 32 has an annular shape, having a central axis coincident with the central axis of the inner shell. In addition, when the assembly 30 is mounted in the engine, the central axes coincide with the central axis A of the engine.

[0084] Each guide vane 33 extends radially from the inner shroud 31 to the outer shroud 32. The guide vanes 33 form a grid for guiding the air flow flowing between the guide vanes 33.

[0085] Figure 3 shows how the guide vanes 33 can be mounted on a ferrule 32.

[0086] In the example illustrated in Figure 3, the guide vanes 33 are identical to each other. Each guide vane 33 comprises a first platform 34, a second platform 35 and a profiled portion 36, extending radially from the first platform 34 to the second platform 35. The first platform 34 is intended to be positioned radially outwardly relative to the second platform 35, relative to the axis A of the engine. In the example illustrated in Figure 3, the guide vanes 33 are mounted on the outer shell 32. However, the guide vanes 33 can also be mounted in the same way on the inner shell 31.

[0087] For this purpose, the first platform 34 of each guide vane 33 comprises protrusions 37 suitable for being engaged in circumferential grooves 38 of the ferrule 32, in order to fix each guide vane 33 on the ferrule 32.

[0088] The guide vanes 33 are thus arranged next to each other over the entire circumference of the shell 32, so as to form a row of guide vanes. The guide vanes 33 of the same row may have a constant angular spacing between two consecutive guide vanes.

[0089] Each first platform 34 has a guide surface from which the profiled portion 36 extends. Similarly, each second platform 35 has a guide surface from which the profiled portion 36 extends.

[0090] Once the guide vanes 33 are mounted, the guide surfaces of the first platforms 34 of the guide vanes 33 form an outer wall of the flow path of the gas flow. The guide surfaces of the second platforms 35 of the guide vanes form an inner wall of the flow path of the gas flow.

[0091] In the example illustrated in Figure 3, the assembly 30 comprises two rows of guide vanes 33 mounted on the shroud 32. However, it would be possible to mount a single row of guide vanes or more than two rows of guide vanes on the same shroud.

[0092] Figure 4 schematically represents two adjacent guide vanes 33A and 33B of the same row, in accordance with a first embodiment of the invention.

[0093] The two guide vanes 33A and 33B are identical to each other.

[0094] Each guide vane 33A, 33B comprises a platform 34A, 34B and a profiled portion 36A, 36B.

[0095] The profiled portion 36A, 36B has a leading edge 41A, 41B, a trailing edge 42A, 42B, a lower surface 43A, 43B and an upper surface 44A, 44B.

[0096] The platform 34A, 34B has a guide surface 45A, 45B from which the profiled portion 36A, 36B extends, a first lateral surface 46A, 46B and a second lateral surface 47A, 47B.

[0097] As illustrated in Figure 4, the second lateral surface 47B is suitable for being arranged opposite the first lateral surface 46A of the adjacent guide vane. More specifically, in the example illustrated in Figure 4, the second lateral surface 47B is suitable for being arranged against the first lateral surface 46A, so that the platforms 34A and 34B of the two adjacent vanes 33A and 33B fit together.

[0098] In this way, the platform 34B of the guide vane 33B delimits with the platform 34A of the adjacent guide vane 33A a flow path for the gas flow flowing between the profiled portion 36B of the guide vane 33B and the profiled portion 36A of the adjacent guide vane 33A.

[0099] The guide surface 45A, 45B of each guide vane 33A, 33B comprises a first guide surface portion 48A, 48B and a second guide surface portion 49A, 49B. The first guide surface portion 48A, 48B extends from the intrados surface 43A, 43B of the profiled portion 36A, 36B to the first lateral surface 46A, 46B. The second guide surface portion 49A, 49B extends from the extrados surface 44A, 44B of the profiled portion 36A, 36B to the second lateral surface 47A, 47B.

[0100] A first joining line 51A, 51B is formed at the intersection between the first guide surface portion 48A, 48B and the first side surface 46A, 46B. When the guide vane 33A, 33B is attached to the shroud 32, the first joining line 51A, 51B has a first radius R1 measured from the central axis A of the shroud 32 in a plane transverse to the central axis A.

[0101] Similarly, a second joining line 52A, 52B is formed at the intersection between the second guide surface portion 49A, 49B and the second side surface 47A, 47B. The second joining line 52A, 52B has a second radius R2 measured from the central axis A of the ferrule 32, in the plane transverse to the central axis A.

[0102] As can be seen in Figure 4, the second radius R2 is greater than the first radius R1, so as to form a step (or a step) between the second guide surface 49B of the guide vane 33B and the first guide surface 48A of the adjacent guide vane 33A.

[0103] Thus, a portion of the second lateral surface 47B is not covered by the first lateral surface 46A and extends into the gas flow, forming a wall preventing parasitic circulation of a portion of the gas flow from the intrados surface 43A of the guide vane 33A to the extrados surface 44B of the guide vane 33B. Furthermore, a third junction line 53A, 53B is formed at the intersection between the first guide surface portion 48A, 48B and the intrados surface 43A, 43B. The third junction line 53A, 53B has a third radius 53 measured from the central axis A of the shroud 32, in the plane transverse to the central axis A.

[0104] Similarly, a fourth joining line 54A, 54B is formed at the intersection between the second guide surface portion 49A, 49B and the extrados surface 44A, 44B. The fourth joining line 54A, 54B has a fourth radius R4 measured from the central axis A of the ferrule 32, in the plane transverse to the central axis A.

[0105] As can be seen in Figure 4, in this first embodiment, the fourth radius R4 is less than the third radius R3.

[0106] In other words, the second guide surface portion 49A, 49B forms a depression near the extrados surface 44A, 44B of the profiled portion 33A, 33B, while it forms a raised portion near the second lateral surface 47A, 47B. This depression makes it possible to compensate for the obstruction generated by the raised portion which has the effect of reducing the passage section of the gas flow between the two profiled portions 36A and 36B.

[0107] Figure 5 schematically represents two adjacent guide vanes 33A, 33B of the same row, in accordance with a second embodiment of the invention.

[0108] This second embodiment is identical to the first embodiment, except that in this second embodiment, the first guide surface portion 48A, 48B and the second guide surface portion 49A, 49B are configured such that the fourth radius R4 is equal to the third radius R3.

[0109] On the other hand, the first ray R1 is less than the third ray R3.

[0110] In other words, in this second embodiment, it is the first guide surface portion 48A, 48B which has a depression near the first lateral surface 46A, 46B. This depression in the first guide surface portion 48A, 48B makes it possible to compensate for the obstruction generated by the raising of the second guide surface portion 49A, 49B near the second lateral surface 47A, 47B, which has the effect of reducing the passage section of the gas flow between the two profiled portions 36A and 36B.

[0111] Figure 6 shows, schematically, in top view, an assembly of two guide vanes 33A and 33B. This view is identical for the two preceding embodiments. As can be seen in Figure 6, the first lateral surface 46A, 46B and the second lateral surface 47A, 47B are not flat.

[0112] More specifically, the first lateral surface 46A, 46B of each platform 34A, 34B has a concave shape and the second lateral surface 47A, 47B of each platform 34A, 34B has a convex shape, intended to fit with the concave shape of the first lateral surface 46A, 46B of the platform of the adjacent guide vane.

[0113] Furthermore, each platform 34A, 34B has a first transverse surface 55A, 55B extending in a first transverse plane P1 located upstream of the leading edge 41A, 41B, and a second transverse surface 56A, 56B extending in a second transverse plane P2 located downstream of the trailing edge 42A, 42B.

[0114] The first junction line 51 A, 51 B extends from the first transverse plane P1 to the second transverse plane P2.

[0115] Likewise, the second junction line 52A, 52B extending from the first transverse plane P1 to the second transverse plane P2.

[0116] The first ray R1 and the second ray R2 vary continuously from the first transverse plane P1 to the second transverse plane P2.

[0117] The third radius R3 and the fourth radius R4 vary continuously from the leading edge 41A, 41B to the trailing edge 42A, 42B of the profiled portion 36A, 36B.

[0118] Figure 6 illustrates three distinct section planes AA, BB and CC, extending transversely with respect to the central axis A of the ferrule 32 by intersecting the profiled portion 36A, 36B.

[0119] Section plane AA is located upstream of section plane BB, which is itself located upstream of section plane CC, in the direction of flow of the gas stream.

[0120] Figures 7A to 7C schematically represent the two guide vanes 33A, 33B respectively in the three different transverse section planes AA, BB and CC, in accordance with the first embodiment.

[0121] As seen in Figure 7A, in the section plane AA, the first ray R1, the second ray R2, the third ray R3 and the fourth ray R4 are equal.

[0122] As can be seen in Figure 7B, in the section plane BB, the second ray R2 is greater than the first ray R1. In addition, the fourth ray R4 is less than the third ray R3. Moreover, a difference between the second ray R2 and the first ray R1 is equal to a difference between the third ray R3 and the fourth ray R4. In other words: R2 - R1 = R3 - R4 and max (R2 - R1) = max (R3 - R4) = h

[0123] As seen in Figure 7C, in the section plane CC, the first ray R1, the second ray R2, the third ray R3 and the fourth ray R4 are again equal.

[0124] Figure 7D shows a variation of the second radius R2 (in solid lines) relative to the first radius R1 between the first transverse plane P1 and the second transverse plane P2, and a variation of the fourth radius R4 (in dotted lines) relative to the third radius R3 between the leading edge 41 and the trailing edge 42.

[0125] The first ray R1 has a constant value from the first transverse plane P1 to the second transverse plane P2.

[0126] On the other hand, as can be seen in Figure 7D, the value of the second ray R2 varies continuously from the first transverse plane P1 to the second transverse plane P2 so that a difference between the second ray R2 and the first ray R1 has a zero value from the first transverse plane P1 to a third transverse plane P3 located between the first transverse plane P1 and the second transverse plane P2, then this difference increases continuously from a zero value in the third transverse plane P3, up to a maximum value h in a fourth transverse plane P4 located between the third transverse plane P3 and the second transverse plane P2, and then this difference decreases continuously from the maximum value in the fourth transverse plane P4 to a zero value in the second transverse plane P2.

[0127] The third transverse plane P3 is defined as a transverse plane passing through a point on the fourth junction line 54 where the curvature of the fourth junction line 54 (and consequently of the extrados surface 44) is maximum.

[0128] In this way, the third transverse plane P3 is located in an area in which shocks are likely to occur due to the flow of the gas stream at high speeds.

[0129] An axial distance between the third transverse plane P3 and the second transverse plane P2 is between 10% and 40% of a chord length of the profiled portion 36, the chord length of the profiled portion 36 being defined as a distance between a point of intersection between the leading edge 41 and the guide surface 45 of the platform 34 and a point of intersection between the trailing edge 42 and the guide surface 45 of the platform 34. The third radius R3 has a constant value from the leading edge 41 to the trailing edge 42.

[0130] On the other hand, as can be seen in Figure 7D, the fourth ray R4 has a value which varies continuously from the leading edge 41 to the trailing edge 42, so that the difference between the second ray R2 and the first ray R1 is always equal to the difference between the third ray R3 and the fourth ray R4, in any transverse plane.

[0131] Thus, the difference between the third ray R3 and the fourth ray R4 has a maximum value h in the fourth transverse plane P4.

[0132] Therefore, in this fourth transverse plane P4, the difference between the second ray R2 and the fourth ray R4 is 2h.

[0133] Figure 7E shows that the first radius R1 is constant from the first transverse plane P1 to the second transverse plane P2 and that the third radius R3 is equal to the first radius R1 from the leading edge 41 to the trailing edge 42 of the profiled portion 36.

[0134] Figures 8A to 8C schematically represent the two guide vanes 33A and 33B in the three different transverse section planes AA, BB and CC, in accordance with the second embodiment.

[0135] As seen in Figure 8A, in the section plane AA, the first ray R1, the second ray R2, the third ray R3 and the fourth ray R4 are equal.

[0136] As can be seen in Figure 8B, in the section plane BB, the second ray R2 is greater than the first ray R1. On the other hand, the third ray R3 and the fourth ray R4 are equal.

[0137] Moreover, a difference between the third ray R3 and the first ray R1 is equal to a difference between the second ray R2 and the fourth ray R4. In other words: R3 - R1 = R2 - R4 and max (R3 - R1) = max (R2 - R4) = h / 2

[0138] As seen in Figure 8C, in the section plane CC, the first ray R1, the second ray R2, the third ray R3 and the fourth ray R4 are again equal.

[0139] Figure 8D shows a variation of the second radius R2 relative to the fourth radius R4, while Figure 8E shows a variation of the first radius R1 relative to the third radius R3 between the first transverse plane P1 and the second transverse plane P2. The fourth radius R4 has a constant value from the leading edge 41 to the trailing edge 42 of the profiled portion 36.

[0140] On the other hand, as can be seen in FIG. 8D, the value of the second radius R2 varies continuously from the first transverse plane P1 to the second transverse plane P2 so that a difference between the second radius R2 and the fourth radius R4 has a zero value from the leading edge 41 to a third transverse plane P3 located between the first transverse plane P1 and the second transverse plane P2, then this difference increases continuously from a zero value in the third transverse plane P3, up to a maximum value h / 2 in a fourth transverse plane P4 located between the third transverse plane P3 and the second transverse plane P2, and then this difference decreases continuously from the maximum value h / 2 in the fourth transverse plane P4 to a zero value in the second transverse plane P2.

[0141] The third transverse plane P3 is defined as a transverse plane passing through a point on the fourth junction line 54 where the curvature of the fourth junction line 54 (and consequently of the extrados surface 44) is maximum.

[0142] In this way, the third transverse plane P3 is located in an area in which shocks are likely to occur due to the flow of the gas stream at high speeds.

[0143] Symmetrically, the third radius R3 has a constant value from the leading edge 41 to the trailing edge 42 of the profiled part 36, equal to the value of the fourth radius R4.

[0144] On the other hand, as can be seen in Figure 8E, the second radius R2 has a value which varies continuously from the leading edge 41 to the trailing edge 42, so that the difference between the third radius R3 and the second radius R2 is always equal to the difference between the second radius R2 and the fourth radius R4, in any transverse plane.

[0145] Thus, the difference between the second ray R2 and the fourth ray R4 has a maximum value h / 2 in the fourth transverse plane P4.

[0146] Similarly, the difference between the third ray R3 and the first ray R1 also has a maximum value h / 2 in the fourth transverse plane P4.

[0147] Therefore, in this fourth transverse plane P4, the difference between the second ray R2 and the first ray R1 is h.

Claims

CLAIMS 1. Guide vane (33) intended to be fixed on a stator shroud (32) of a gas turbine engine (1), comprising: - a profiled portion (36) intended to extend into a gas flow to guide the gas flow, the profiled portion (36) having an intrados surface (43) and an extrados surface (44), and - a platform (34) having a guide surface (45) from which the profiled portion (36) extends, a first lateral surface (46) and a second lateral surface (47), the second lateral surface (47) being suitable for being arranged opposite a first lateral surface (46) of an identical adjacent guide vane, such that the platform (34) of the guide vane (33) delimits with the platform of the adjacent guide vane a flow path for the gas flow flowing between the profiled portion (36) of the guide vane (33) and the profiled portion of the adjacent guide vane, the guide surface (45) comprising a first guide surface portion (48) extending from the intrados surface (43) of the profiled portion (36) to the first lateral surface (46) and a second guide surface portion (49) extending from the extrados surface (44) from the profiled part (36) to the second lateral surface (47),wherein a first joining line (51) is formed at the intersection between the first guide surface portion (48) and the first side surface (46), a second joining line (52) is formed at the intersection between the second guide surface portion (49) and the second side surface (47), a third joining line (53) is formed at the intersection between the first guide surface portion (48) and the lower surface (43), and a fourth joining line (54) is formed at the intersection between the second guide surface portion (49) and the upper surface (44), the first guide surface portion (48) and the second guide surface portion (49) being configured such that when the guide vane (33) is attached to the shroud (32), the first joining line (51) has a first radius (R1) measured from the central axis (A) of the shroud (32) in a plane transverse to the central axis,the second junction line (52) has a second radius (R2) measured from the central axis (A), in the plane transverse to the central axis, the second radius, (R2) being greater than the first radius (R1), the third junction line (53) has a third radius (R3) measured from the central axis (A), in the plane transverse to the central axis, and the fourth junction line (54) has a fourth radius (R4) measured from the central axis (A), in the plane transverse to the central axis, the fourth radius (R4) being less than or equal to the third radius (R3).

2. A guide vane (33) according to claim 1, wherein the first radius (R1) is equal to the third radius (R3), and the fourth radius (R4) is less than the third radius (R3).

3. A guide vane (33) according to claim 2, wherein a difference between the second radius (R2) and the first radius (R1) is equal to a difference between the third radius (R3) and the fourth radius (R4).

4. Guide vane (33) according to claim 1, in which the fourth radius (R4) is equal to the third radius (R3).

5. A guide vane (33) according to claim 4, wherein a difference between the second radius (R2) and the fourth radius (R4) is equal to a difference between the third radius (R3) and the first radius (R1).

6. Guide vane (33) according to one of claims 1 to 5, in which the profiled part (36) has a leading edge (41) and a trailing edge (42), and the platform (34) has a first transverse surface (55) extending in a first transverse plane (P1) located upstream of the leading edge (41), and a second transverse surface (56) extending in a second transverse plane (P2) located downstream of the trailing edge (42), the first junction line (51) extending from the first transverse plane (P1) to the second transverse plane (P2) and the second junction line (52) extending from the first transverse plane (P1) to the second transverse plane (P2), and in which a difference between the second radius (R2) and the first radius (R1) has a zero value from the first plane transverse (P1) to a third transverse plane (P3) located between the first transverse plane (P1) and the second transverse plane (P2),then which increases continuously from a zero value in the third transverse plane (P3), up to a maximum value in a fourth transverse plane (P4) located between the third transverse plane (P3) and the, second transverse plane (P2), and which decreases continuously from the maximum value in the fourth transverse plane (P4) to a zero value in the second transverse plane (P2).

7. A guide vane (33) according to claim 6, wherein the third transverse plane (P3) is defined as a transverse plane passing through a point on the fourth junction line (54) where the curvature of the fourth junction line (54) is maximum.

8. Guide vane (33) according to one of claims 6 and 7, in which the first junction line (51) has a first radius (R1) having a constant value from the first transverse plane (P1) to the second transverse plane (P2).

9. Guide vane (33) according to one of claims 6 and 7, in which the first junction line (51) has a first radius (R1) having a constant value from the first transverse plane (P1) to the third transverse plane (P3), then which decreases continuously from the third transverse plane (P3) to the fourth transverse plane (P4), and which increases continuously from the fourth transverse plane (P4) to the second transverse plane (P2).

10. Guide vane (33) according to one of claims 6 to 9, in which the second junction line (52) has a second radius (R2) having a constant value from the first transverse plane (P1) to the third transverse plane (P3), then which increases continuously from the third transverse plane (P3) to the fourth transverse plane (P4), and which decreases continuously from the fourth transverse plane (P4) to the second transverse plane (P2).

11. Guide vane (33) according to one of claims 6 to 10, wherein an axial distance between the third transverse plane (P3) and the second transverse plane (P2) is between 10% and 40% of a chord length of the profiled portion (36), the chord length of the profiled portion (36) being defined as a distance between a point of intersection between the leading edge (41) and the guide surface (45) of the platform (34) and a point of intersection between the trailing edge (42) and the guide surface (45) of the platform (34).

12. Gas turbine engine stator assembly (30), comprising: - a ferrule (32) having a central axis (A), - a guide vane assembly (33) comprising a plurality of guide vanes, each guide vane (33) comprising a platform (34) having a guide surface (45) and a profiled portion (36) extending radially from the guide surface (45) of the platform, the profiled portion (36) having a lower surface (43) and an upper surface (44), and the platform (34) having a first lateral surface (46) and a second lateral surface (47), and the guide surface (45) of the platform comprising a first guide surface portion (48) extending from the lower surface (43) of the profiled portion (36) to the first lateral surface (46) and a second guide surface portion (49) extending from the upper surface (44) of the profiled portion (36) to the second lateral surface (47),the guide vanes (33) being fixed to the shroud (32) such that the second lateral surface (47) of each guide vane (33) is arranged opposite a first lateral surface (46) of an adjacent guide vane of the set of guide vanes, and the first guide surface portions (48) and the second guide surface portions (49) of the platforms (34) define a flow path for a gas stream flowing between the profiled portions (36) of the guide vanes, wherein each guide vane (33) has a first junction line (51) formed at the intersection between the first guide surface portion (48) and the first lateral surface (46), a second junction line (52) formed at the intersection between the second guide surface portion (49) and the second lateral surface (47), a third junction line (53) formed at the intersection between the first guide surface portion (48) and the intrados surface (43),and a fourth joining line (54) formed at the intersection between the second guide surface portion (49) and the suction surface (44), and wherein the first joining line (51) has a first radius (R1) measured from the central axis (A), in a plane transverse to the central axis, the second joining line (52) has a second radius (R2) measured from the central axis (A), in the plane transverse to the central axis, the second radius (R2) being greater than the first radius (R1), such that a portion of the second lateral surface (47) extends into the gas flow forming a wall preventing parasitic circulation of a portion of the gas flow from the suction surface (43) of a guide vane (33A) to the suction surface (44) of an adjacent guide vane, (33B), the third connecting line (53) has a third radius (R3) measured from the central axis (A), in the plane transverse to the central axis, and the fourth connecting line (54) has a fourth radius (R4) measured from the central axis (A), in the plane transverse to the central axis, the fourth radius (R4) being less than or equal to the third radius (R3).

13. Assembly (30) according to claim 12, wherein each guide vane (33) is in accordance with one of claims 2 to 11.

14. Assembly (30) according to one of claims 12 and 13, in which the guide vanes (33) of the set of guide vanes are identical to each other.

15. Assembly (30) according to one of claims 12 to 14, in which the shroud is an internal shroud (31) of a rectifier and the guide surfaces of the platforms of the guide vanes (33) form an internal wall of the flow vein of the gas flow.

16. Assembly (30) according to one of claims 12 to 14, in which the shroud is an external shroud (32) of a rectifier and the guide surfaces of the platforms (34) of the guide vanes (33) form an external wall of the flow vein of the gas flow.

17. The assembly (30) of one of claims 12 to 16, wherein the assembly is a compressor stator rectifier assembly or a turbine stator rectifier assembly or a fan rectifier assembly.

18. Gas turbine engine (1) comprising an assembly (30) according to one of claims 12 to 17.

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