Guide vane for attachment to stator shroud of 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, the guide vane comprising:-a shaped part (36B) intended to extend into a gas flow to direct the gas flow, the shaped part (36B) having an inner arc surface (43B) and an outer arc surface (44B), and-a platform (34B) for supporting the shaped part (36B), the present invention relates to a guide vane (33A) comprising a platform having a guide surface (45B), a first side surface (46B) and a second side surface (47B) from which a molded part (36B) extends, the second side surface (47B) being arrangeable to face the first side surface (46A) of the same adjacent guide vane (33A), thereby forming a projection preventing parasitic lateral flow of a gas flow, a recess is created that at least partially compensates for the obstruction of the projection to the gas flow.

Description

Technical Field

[0001] The invention relates to a guide vane for fixing to 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. Background Art

[0002] A gas turbine engine typically includes a fan section, a compressor section, a combustor, and a turbine section.

[0003] The fan section, compressor section, and turbine section each include a rotating component (or "rotor") and a stationary component (or "stator").

[0004] For example, the fan section includes a fan housing and a fan rotor that can be driven to rotate relative to the fan housing. The fan rotor includes one or more rows of blades. The rotation of the fan rotor has the following effect: compressing the air discharged backward to generate a part of the engine thrust.

[0005] In addition, the fan section usually includes a set of outlet guide vanes (OGV), which are arranged downstream of the fan rotor and used as straighteners. This set of vanes has the following functions: straightening and adjusting the air flow flowing downstream of the fan rotor to optimize the engine thrust. This set of vanes also plays a role in noise reduction.

[0006] The air flow through the set of blades generally flows between the blades in an upstream-downstream direction. However, secondary aerodynamic flows may occur near the root of the blades.

[0007] In fact, for each pair of blades facing each other, the pressure gradient between the pressure surface of a blade (inner arc surface) and the concave surface of an adjacent blade (outer arc surface) creates a parasitic cross flow that transports air from the inner arc surface to the outer arc surface of the adjacent blade.

[0008] Furthermore, at the blade tip, that is to say at the junction between the blade and the inner shroud of the casing or at the junction between the blade and the outer shroud of the casing, angular separation and angular vortices may occur. This separation generates pressure losses and aerodynamic blockages. This aerodynamic blockage is problematic in terms of operability. For high angles of incidence of the air flow reaching the blade, that is to say when the direction of the air flow upstream of the blade forms a significant angle with the direction of the leading edge of the blade, this angular separation increases to the point of causing boundary layer separation on the aerodynamic part of the blade, which point can no longer ensure flow deflection.

[0009] Another set of blades of the engine is affected by this phenomenon, in particular in the set of blades of the straightener facing the sets of blades in the compressor, or in the sets of blades of the distributor facing the sets of blades in the turbine.

[0010] To overcome this problem, one solution consists in inserting a fin between two adjacent blades, the function of which is to block the transverse gas flow from the inner arc surface of a blade to the outer arc surface of an adjacent blade. Document FR 3 106 614 describes an example of a fin.

[0011] However, a disadvantage of this solution is that it requires the manufacture and installation of additional components (fins).

[0012] It is also possible to machine the fins directly into the platform of the blade. However, this would complicate the manufacture of the blade. Summary of the invention

[0013] One object of the present invention is to propose a solution for blocking parasitic flows in groups of blades while limiting obstruction of the gas flow duct.

[0014] This problem is solved within the framework of the present invention by a guide vane, which is intended to be fastened to a stator shroud of a gas turbine engine, comprising:

[0015] - a shaped part, the shaped part is intended to extend into the gas flow to guide the gas flow, the shaped part having an inner arc surface and an outer arc surface, and

[0016] a platform having a guide surface, a first side surface and a second side surface, the shaped part extending from the guide surface, the second side surface being able to be arranged facing the first side surface of the same adjacent guide vane, so that the platform of the guide vane and the platform of the adjacent guide vane define a flow path for a gas flow, said gas flow flowing between the shaped part of the guide vane and the shaped part of the adjacent guide vane,

[0017] The guide surface includes a first guide surface portion and a second guide surface portion, the first guide surface portion extends from the inner arc surface of the molding component to the first side surface, and the second guide surface portion extends from the outer arc surface of the molding component to the second side surface,

[0018] wherein a first joining line is formed at an intersection between the first guide surface portion and the first side surface, a second joining line is formed at an intersection between the second guide surface portion and the second side surface, a third joining line is formed at an intersection between the first guide surface portion and the inner arc surface, and a fourth joining line is formed at an intersection between the second guide surface portion and the outer arc surface,

[0019] The first guide surface portion and the second guide surface portion are configured such that when the guide vane is secured to the shroud, the first join line has a first radius measured from the central axis of the shroud in a plane transverse to the central axis, the second join line has a second radius measured from the central axis in a plane transverse to the central axis, the second radius being greater than the first radius, the third join line has a third radius measured from the central axis in a plane transverse to the central axis, and the fourth join line has a fourth radius measured from the central axis in a plane transverse to the central axis, the fourth radius being less than or equal to the third radius.

[0020] The second radius, which is larger than the first radius, enables a step (or recess) to be created between the second guide surface of the guide vane and the first guide surface of the adjacent guide vane, thereby preventing a portion of the gas flow from parasitically flowing from the inner arc surface of the guide vane to the outer arc surface of the guide vane.

[0021] Thus, the second guide surface has an additional height relative to the first guide surface.

[0022] However, the fourth radius remains smaller than or equal to the third radius. This enables the creation of a recess that compensates for the obstruction of the pipe due to the presence of the extra height.

[0023] The proposed guide vanes may also have the following features:

[0024] - the first radius is equal to the third radius, and the fourth radius is smaller than the third radius;

[0025] - the difference between the second radius and the first radius is equal to the difference between the third radius and the fourth radius;

[0026] - the fourth radius is equal to the third radius;

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

[0028] - the profiled component has a leading edge and a trailing edge, 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 extends from the first transverse plane to the second transverse plane, and the second joining line extends from the first transverse plane to the second transverse plane, and wherein the 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 and second transverse planes, then the difference increases continuously from the zero value in the third transverse plane to a maximum value in a fourth transverse plane located between the third and second transverse planes, and then the difference decreases continuously from the maximum value in the fourth transverse plane to a zero value in the second transverse plane;

[0029] - a third transverse plane is defined as a transverse plane passing through the point on the fourth joining line at which the curvature of the fourth joining line is maximum;

[0030] - the first joining line has a first radius having a constant value from the first transverse plane to the second transverse plane;

[0031] the first joining line has a first radius which has a constant value from the first transverse plane to the third transverse plane, then decreases continuously from the third transverse plane to the fourth transverse plane, and increases continuously from the fourth transverse plane to the second transverse plane;

[0032] the second joining line has a second radius which has a constant value from the first transverse plane to the third transverse plane, then increases continuously from the third transverse plane to the fourth transverse plane, and decreases continuously from the fourth transverse plane to the second transverse plane;

[0033] The axial distance between the third transverse plane and the second transverse plane is between 10% and 40% of the chord length of the profiled part, the chord length of the profiled part being defined as the distance between the intersection point between the leading edge and the guide surface of the platform and the intersection point between the trailing edge and the guide surface of the platform.

[0034] The present invention also relates to a gas turbine engine stator assembly, the gas turbine engine stator assembly comprising:

[0035] - a shield having a central axis,

[0036] - a set of guide blades comprising a plurality of guide blades,

[0037] Each guide vane includes a platform and a shaped part, the platform having a guide surface, the shaped part extending radially from the guide surface of the platform, the shaped part having an inner arc surface and an outer arc surface, and the platform having a first side surface and a second side surface, the guide surface of the platform including a first guide surface portion and a second guide surface portion, the first guide surface portion extending from the inner arc surface of the shaped part to the first side surface, the second guide surface portion extending from the outer arc surface of the shaped part to the second side surface,

[0038] The guide vanes are fixed to the shroud so that the second side surface of each guide vane is arranged to face the first side surface of an adjacent guide vane in the set of guide vanes, the first guide surface portion and the second guide surface portion of the platform defining a flow path for a gas flow flowing between the shaped parts of the guide vanes,

[0039] wherein each guide vane has a first joining line, a second joining line, a third joining line and a fourth joining line, the first joining line being formed at an intersection between the first guide surface portion and the first side surface, the second joining line being formed at an intersection between the second guide surface portion and the second side surface, the third joining line being formed at an intersection between the first guide surface portion and the inner arc surface, and the fourth joining line being formed at an intersection between the second guide surface portion and the outer arc surface,

[0040] And wherein the first joining line has a first radius measured from the central axis in a plane transverse to the central axis, the second joining line has a second radius measured from the central axis in a plane transverse to the central axis, the second radius is greater than the first radius, so that a portion of the second side surface extends into the gas flow by forming a wall that prevents a portion of the gas flow from parasitically flowing from the inner arc surface of the guide vane to the outer arc surface of an adjacent guide vane, the third joining line has a third radius measured from the central axis in a plane transverse to the central axis, and the fourth joining line has a fourth radius measured from the central axis in a plane transverse to the central axis, the fourth radius is less than or equal to the third radius.

[0041] In such an assembly, each guide vane may have one of the features defined above.

[0042] The guide vanes of the set of guide vanes can be identical to one another.

[0043] In one possible embodiment, the shroud is an inner straightener shroud, the guide surfaces of the platforms of the guide vanes forming the inner wall of the gas stream flow duct.

[0044] In another possible embodiment, the shroud is an outer straightener shroud, the guide surfaces of the platforms of the guide vanes forming the outer wall of the gas stream flow duct.

[0045] The assembly may be a compressor stator straightener assembly or a turbine stator straightener assembly or a fan straightener assembly.

[0046] The invention also relates to a gas turbine engine comprising an assembly as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Other features and advantages will be apparent from the following description which is intended to be illustrative only and non-limiting and which should be read in conjunction with the accompanying drawings, in which:

[0048] - Figure 1 A gas turbine engine is schematically shown in longitudinal section,

[0049] - Figure 2 A stator straightener assembly of a gas turbine engine is schematically shown,

[0050] - Figure 3 The guide vanes assembled on the stator shroud are schematically shown.

[0051] - Figure 4 Schematically shows an assembly of two guide vanes according to a first embodiment of the present invention,

[0052] - Figure 5 Schematically shows an assembly of two guide vanes according to a second embodiment of the present invention,

[0053] - Figure 6 A schematic top view of an assembly of two guide vanes is shown,

[0054] - FIG. 7A to FIG. 7C Schematically shows two guide vanes according to a first embodiment located in three different transverse cutting planes,

[0055] - Fig.7D A schematic diagram shows a side view of the outer arc portion of one of the guide vanes of the assembly,

[0056] - Fig. 7E schematically shows a side view of the inner arc portion of another guide vane of the assembly,

[0057] - FIG. 8A to FIG. 8C Schematically shows two guide vanes according to a second embodiment located in three different transverse cutting planes,

[0058] - Fig.8D A schematic diagram shows a side view of the outer arc portion of one of the guide vanes of the assembly,

[0059] - Fig. 8E A side view of the inner arc portion of another guide vane of the assembly is schematically shown. DETAILED DESCRIPTION

[0060] exist Figure 1 In FIG. 1 , the gas turbine engine 1 shown is a twin-body turbofan gas turbine engine.

[0061] The gas turbine engine 1 has a longitudinal axis Δ.

[0062] The gas turbine engine 1 includes a nacelle 2 , a fan section 3 , a compressor section 4 , a combustion chamber 5 and a turbine section 6 .

[0063] exist Figure 1In the example shown, the fan section 3 includes a fan casing 7, a fan 8 and outlet guide vanes (OGV) 9, wherein the fan casing 7 is fixedly mounted relative to the nacelle, the fan 8 can be driven to rotate relative to the fan casing 7, and the outlet guide vanes 9 are fixedly mounted on the fan casing 7 and have the function of straightening the secondary air flow flowing at the outlet of the fan 8.

[0064] exist Figure 1 In the example shown, compressor section 4 includes a low-pressure compressor 10 and a high-pressure compressor 11 .

[0065] Furthermore, the turbine section 6 includes a high-pressure turbine 12 and a low-pressure turbine 13 .

[0066] The gas turbine engine 1 comprises a low-pressure shaft 14 connecting the low-pressure turbine 13 to the low-pressure compressor 10 and 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 Δ of the engine.

[0067] The fan 8, the low-pressure compressor 10, the low-pressure turbine 13 and the low-pressure shaft 14 together form a low-pressure body of the engine 1. The low-pressure turbine 13 can drive the low-pressure compressor 10 and the fan 8 to rotate via the low-pressure shaft 14.

[0068] More specifically, the low-pressure compressor 10 comprises a low-pressure compressor housing 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 can be driven to rotate relative to the low-pressure compressor stator 18 about the longitudinal axis Δ of the engine 1. The low-pressure compressor rotor 17 comprises blades. The low-pressure compressor stator 18 comprises vanes (also called "guide vanes" or "straightener vanes"), which are fixedly mounted on the low-pressure compressor housing 16 by being inserted between the blades. These vanes have the function of guiding the main air flow through the low-pressure compressor 10.

[0069] Similarly, the low-pressure turbine 13 comprises a low-pressure turbine housing 19 fixedly mounted relative to the nacelle 2, a low-pressure turbine rotor 20 and a low-pressure turbine stator 21. The low-pressure turbine rotor 20 can be driven to rotate relative to the low-pressure turbine stator 21 around the longitudinal axis Δ of the engine 1. The low-pressure turbine rotor 20 comprises blades. The low-pressure turbine stator 21 comprises vanes, which are fixedly mounted on the low-pressure turbine housing 19 by being inserted between the blades. These vanes have the function of guiding the main air flow through the low-pressure turbine 13.

[0070] The low-pressure turbine rotor 20 is connected to the low-pressure compressor rotor 17 via the low-pressure shaft 14. Therefore, when the engine 1 is running, the rotation of the low-pressure turbine rotor 20 causes the rotation of the low-pressure compressor rotor 17.

[0071] The high-pressure compressor 11, the high-pressure turbine 12 and the high-pressure shaft 15 together form a high-pressure body of the engine 1. The high-pressure turbine 12 can drive the high-pressure compressor 11 to rotate via the high-pressure shaft 15.

[0072] More specifically, the high-pressure compressor 11 comprises a high-pressure compressor housing 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 can be driven to rotate relative to the high-pressure compressor stator 24 about the longitudinal axis Δ of the engine 1. The high-pressure compressor rotor 23 comprises blades. The high-pressure compressor stator 24 comprises vanes (also called "guide vanes" or "straightener vanes"), which are fixedly mounted on the high-pressure compressor housing 22 by being inserted between the blades. These vanes have the function of guiding the main air flow through the high-pressure compressor 11.

[0073] Likewise, the high-pressure turbine 12 comprises a high-pressure turbine housing 25 fixedly mounted relative to the nacelle 2, a high-pressure turbine rotor 26 and a high-pressure turbine stator 27. The high-pressure turbine rotor 26 can be driven to rotate relative to the high-pressure turbine stator 27 about the longitudinal axis Δ of the engine 1. The high-pressure turbine rotor 26 comprises blades. The high-pressure turbine stator 27 comprises vanes, which are fixedly mounted on the high-pressure turbine housing 25 by being inserted between the blades. These vanes have the function of guiding the main air flow through the high-pressure turbine 12.

[0074] The high-pressure turbine rotor 26 is connected to the high-pressure compressor rotor 23 via the high-pressure shaft 15. Therefore, when the engine 1 is running, the rotation of the high-pressure turbine rotor 26 causes the rotation of the high-pressure compressor rotor 23.

[0075] The outlet guide vanes 9 of the fan section 3 , the blades of the stator 18 of the low-pressure compressor 10 , the blades of the high-pressure compressor stator 24 , the blades of the high-pressure turbine stator 27 and the blades of the low-pressure turbine stator 21 are examples of guide vanes.

[0076] When the engine 1 is running, the fan 8 and the low-pressure compressor 10 are driven to rotate by the low-pressure turbine 13. Similarly, the high-pressure compressor 11 is driven to rotate by the high-pressure turbine 12.

[0077] The air is sucked by the fan 8. The air sucked by the fan 8 is divided into a primary air flow and a secondary air flow that flows from the upstream to the downstream of the gas turbine engine 1.

[0078] The main air flow flows in the main duct from upstream to downstream of the gas turbine engine 1, passing through the low-pressure compressor 10, the high-pressure compressor 11, the combustion chamber 5, the high-pressure turbine 12 and the low-pressure turbine 13 in sequence, where the main air flow is mixed with fuel to be used as an oxidant. The passage of the main air flow through the high-pressure turbine 12 and the low-pressure turbine 13 causes the rotation of the rotors 26 and 29 of the turbines, which in turn drive the rotors 23 and 17 of the high-pressure compressor and the low-pressure compressor and the fan 8 to rotate via the high-pressure shaft 15 and the low-pressure shaft 14. The main air flow escapes from the engine 1 through the exhaust casing 28 located downstream of the low-pressure turbine casing 19.

[0079] The secondary air flow (also called "bypass air flow") flows from upstream to downstream of the gas turbine engine 1 in the secondary duct. The secondary air flow does not enter the combustion chamber 5 and does not drive the turbines 12 and 13. The secondary air flow is used to cool the periphery of the engine body and to generate most of the thrust provided by the gas turbine engine. The secondary air flow flows through the blades 9 mounted on the fan housing 7 and located downstream of the fan 8.

[0080] Figure 2 The stator straightener assembly 30 of the gas turbine engine 1 is schematically shown. Figure 2 In the example shown, the assembly 30 is a fan straightener assembly. However, the assembly 30 may be a compressor stator straightener assembly or a turbine stator straightener assembly.

[0081] The assembly 30 includes an inner shroud 31 , an outer shroud 32 extending around the inner shroud 31 , and a series of guide vanes 33 .

[0082] The inner shroud 31 has an annular shape with a central axis. Similarly, the outer shroud 32 has an annular shape with a central axis, and the central axis of the outer shroud coincides with the central axis of the inner shroud. In addition, when the assembly 30 is installed in the engine, the central axis of the assembly coincides with the central axis of the engine by Δ.

[0083] Each guide vane 33 radially extends from the inner shroud 31 to the outer shroud 32. The guide vanes 33 form a cascade for guiding an air flow flowing between the guide vanes 33.

[0084] Figure 3 It is shown how the guide vanes 33 are mounted on the shroud 32 .

[0085] exist Figure 3 In the example shown, the guide vanes 33 are identical to one another. Each guide vane 33 comprises a first platform 34, a second platform 35 and a profiled part 36 extending radially from the first platform 34 to the second platform 35. The first platform 34 is intended to be positioned radially outwards relative to the second platform 35, relative to the axis Δ of the engine.

[0086] exist Figure 3 In the example shown, the guide vanes 33 are mounted on the outer shroud 32. However, the guide vanes 33 can also be mounted on the inner shroud 31 in the same manner.

[0087] To this end, the first platform 34 of each guide vane 33 comprises a projection 37 capable of engaging in a circumferential groove 38 of the shroud 32 in order to secure each guide vane 33 to the shroud 32 .

[0088] The guide vanes 33 are thus arranged adjacent to one another over the entire circumference of the shroud 32 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 a molding part 36 extends. Similarly, each second platform 35 has a guide surface from which a molding part 36 extends.

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

[0091] exist Figure 3 In the example shown, the assembly 30 comprises two rows of guide vanes 33 mounted on a shroud 32. However, a single row of guide vanes or more than two rows of guide vanes may be mounted on the same shroud.

[0092] Figure 4 Two adjacent guide vanes 33A and 33B of the same row according to a first embodiment of the invention are schematically shown.

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

[0094] Each guide vane 33A, 33B includes a platform 34A, 34B and a shaped part 36A, 36B.

[0095] The molding members 36A, 36B have leading edges 41A, 41B, trailing edges 42A, 42B, inner arc surfaces 43A, 43B, and outer arc surfaces 44A, 44B.

[0096] The platforms 34A, 34B have guide surfaces 45A, 45B from which the molding members 36A, 36B, the first side surfaces 46A, 46B and the second side surfaces 47A, 47B extend.

[0097] like Figure 4 As shown, the second side surface 47B can be arranged to face the first side surface 46A of the adjacent guide vane. Figure 4 In the example shown, the second side surface 47B can be arranged to abut against the first side surface 46A so that the platforms 34A and 34B of two adjacent buckets 33A and 33B fit together.

[0098] In this manner, the platform 34B of the guide vane 33B and the platform 34A of the adjacent guide vane 33A define a flow path for the gas flow flowing between the shaped part 36B of the guide vane 33B and the shaped part 36A of the adjacent guide vane 33A.

[0099] The guide surface 45A, 45B of each guide vane 33A, 33B includes 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 inner arc surface 43A, 43B of the molding part 36A, 36B to the first side surface 46A, 46B. The second guide surface portion 49A, 49B extends from the outer arc surface 44A, 44B of the molding part 36A, 36B to the second side surface 47A, 47B.

[0100] The first joint 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 vanes 33A, 33B are fixed to the shroud 32, the first joint line 51A, 51B has a first radius R1 measured from the center axis Δ of the shroud 32 in a plane transverse to the center axis Δ.

[0101] Similarly, second join lines 52A, 52B are formed at the intersection between second guide surface portions 49A, 49B and second side surfaces 47A, 47B. Second join lines 52A, 52B have a second radius R2 measured from the central axis Δ of shroud 32 in a plane transverse to the central axis Δ.

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

[0103] Therefore, a portion of the second side surface 47B is not covered by the first side surface 46A, and a portion of the second side surface 47B extends into the gas flow by forming a wall that prevents a portion of the gas flow from parasitically flowing from the inner arc surface 43A of the guide vane 33A to the outer arc surface 44B of the guide vane 33B.

[0104] Furthermore, a third joint line 53A, 53B is formed at the intersection between the first guide surface portion 48A, 48B and the inner arc surface 43A, 43B. The third joint line 53A, 53B has a third radius 53 measured from the central axis Δ of the shroud 32 in a plane transverse to the central axis Δ.

[0105] Similarly, fourth join lines 54A, 54B are formed at the intersection between second guide surface portions 49A, 49B and outer arc surfaces 44A, 44B. Fourth join lines 54A, 54B have a fourth radius R4 measured from the central axis Δ of shroud 32 in a plane transverse to the central axis Δ.

[0106] like Figure 4 It can be seen that in the first embodiment, the fourth radius R4 is smaller than the third radius R3.

[0107] In other words, the second guide surface portions 49A, 49B form a recessed portion near the outer arc surfaces 44A, 44B of the molding parts 33A, 33B, while the second guide surface portions 49A, 49B form an extra height near the second side surfaces 47A, 47B. The recessed portion makes it possible to compensate for the obstruction caused by the extra height, which has the effect of reducing the passage section of the gas flow between the two molding parts 36A and 36B.

[0108] Figure 5 Two adjacent guide vanes 33A, 33B of the same row according to a second embodiment of the invention are schematically shown.

[0109] The second embodiment is the same as the first embodiment, except that in the second embodiment, the first guide surface portions 48A, 48B and the second guide surface portions 49A, 49B are configured such that the fourth radius R4 is equal to the third radius R3.

[0110] On the other hand, the first radius R1 is smaller than the third radius R3.

[0111] In other words, in this second embodiment, the first guide surface portions 48A, 48B have a recess near the first side surfaces 46A, 46B. This recess in the first guide surface portions 48A, 48B makes it possible to compensate for the obstruction caused by the extra height of the second guide surface portions 49A, 49B near the second side surfaces 47A, 47B, which has the effect of reducing the passage section of the gas flow between the two molding parts 36A and 36B.

[0112] Figure 6 The assembly of two guide vanes 33A and 33B is schematically shown in a top view. This view is identical for the two previously described embodiments.

[0113] like Figure 6It can be seen that the first side surfaces 46A, 46B and the second side surfaces 47A, 47B are not planar.

[0114] More specifically, the first side surface 46A, 46B of each platform 34A, 34B has a concave shape and the second side surface 47A, 47B of each platform 34A, 34B has a convex shape intended to cooperate with the concave shape of the first side surface 46A, 46B of the platform of the adjacent guide vane.

[0115] Furthermore, each platform 34A, 34B has a first transverse surface 55A, 55B extending in a first transverse plane P1 upstream of the leading edge 41A, 41B, and a second transverse surface 56A, 56B extending in a second transverse plane P2 downstream of the trailing edge 42A, 42B.

[0116] The first joining lines 51A, 51B extend from the first transverse plane P1 to the second transverse plane P2.

[0117] Likewise, the second joining lines 52A, 52B extend from the first transverse plane PI to the second transverse plane P2.

[0118] The first radius R1 and the second radius R2 vary continuously from the first transverse plane P1 to the second transverse plane P2.

[0119] 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 molding member 36A, 36B.

[0120] Figure 6 Three different cutting planes AA, BB and CC extending transversely to the central axis Δ of the shroud 32 through the cutting profiled features 36A, 36B are shown.

[0121] Cutting plane AA is located upstream of cutting plane BB in the flow direction of the gas stream, which itself is located upstream of cutting plane CC.

[0122] FIG. 7A to FIG. 7C Schematically shown are two guide vanes 33A, 33B according to a first embodiment in three different transverse cutting planes AA, BB and CC, respectively.

[0123] like Fig. 7A It can be seen that in the cutting plane AA, the first radius R1, the second radius R2, the third radius R3 and the fourth radius R4 are equal.

[0124] like Figure 7BIt can be seen that in the cutting plane BB, the second radius R2 is larger than the first radius R1. In addition, the fourth radius R4 is smaller than the third radius R3.

[0125] In addition, the difference between the second radius R2 and the first radius R1 is equal to the difference between the third radius R3 and the fourth radius R4.

[0126] In other words: R2-R1=R3-R4, maximum (R2-R1)=maximum (R3-R4)=h

[0127] like Figure 7C It can be seen that in the cutting plane CC, the first radius R1 , the second radius R2 , the third radius R3 and the fourth radius R4 are equal again.

[0128] Fig.7D The variation of the second radius R2 (solid line) between the first and second transverse planes P1 and P2 relative to the first radius R1 and the variation of the fourth radius R4 (dashed line) between the leading edge 41 and the trailing edge 42 relative to the third radius R3 are shown.

[0129] The first radius R1 has a constant value from the first transverse plane P1 to the second transverse plane P2.

[0130] On the contrary, Fig.7D It can be seen that the value of the second radius R2 changes continuously from the first transverse plane P1 to the second transverse plane P2, so that the difference between the second radius R2 and the first radius 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, and then the difference continuously increases from the zero value in the third transverse plane P3 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 the difference continuously decreases from the maximum value in the fourth transverse plane P4 to a zero value in the second transverse plane P2.

[0131] The third transverse plane P3 is defined as a transverse plane passing through the point of the fourth joint line 54 where the curvature of the fourth joint line 54 (and thus the outer arc surface 44 ) is greatest.

[0132] In this way, the third transverse plane P3 is located in a zone where impacts may occur due to the high speed of the gas stream.

[0133] The axial distance between the third transverse plane P3 and the second transverse plane P2 is between 10% and 40% of the chord length of the forming part 36, and the chord length of the forming part 36 is defined as the distance between the intersection between the leading edge 41 and the guide surface 45 of the platform 34 and the intersection between the trailing edge 42 and the guide surface 45 of the platform 34.

[0134] The third radius R3 has a constant value from the leading edge 41 to the trailing edge 42 .

[0135] On the other hand, Fig.7D It can be seen that the fourth radius R4 has a value that varies continuously from the leading edge 41 to the trailing edge 42 , so that in any transverse plane, the difference between the second radius R2 and the first radius R1 is always equal to the difference between the third radius R3 and the fourth radius R4 .

[0136] Thus, the difference between the third radius R3 and the fourth radius R4 has a maximum value h in the fourth transverse plane P4.

[0137] Thus, in this fourth transverse plane P4, the difference between the second radius R2 and the fourth radius R4 is 2h.

[0138] Fig. 7E It is shown that the first radius R1 is constant from the first transverse plane P1 to the second transverse plane P2 , and the third radius R3 is equal to the first radius R1 from the leading edge 41 to the trailing edge 42 of the molding feature 36 .

[0139] FIG. 8A to FIG. 8C Two guide vanes 33A and 33B according to a second embodiment are schematically shown in three different transverse cutting planes AA, BB and CC.

[0140] like Fig. 8A It can be seen that in the cutting plane AA, the first radius R1, the second radius R2, the third radius R3 and the fourth radius R4 are equal.

[0141] like Figure 8B It can be seen that in the cutting plane BB, the second radius R2 is greater than the first radius R1. On the other hand, the third radius R3 and the fourth radius R4 are equal.

[0142] In addition, the difference between the third radius R3 and the first radius R1 is equal to the difference between the second radius R2 and the fourth radius R4.

[0143] In other words: R3-R1=R2-R4, maximum (R3-R1)=maximum (R2-R4)=h / 2

[0144] like Figure 8C It can be seen that in the cutting plane CC, the first radius R1 , the second radius R2 , the third radius R3 and the fourth radius R4 are equal again.

[0145] Fig.8D shows the change of the second radius R2 relative to the fourth radius R4, and Fig. 8E The variation of the first radius R1 relative to the third radius R3 between the first transverse plane P1 and the second transverse plane P2 is shown.

[0146] The fourth radius R4 has a constant value from the leading edge 41 to the trailing edge 42 of the profiled part 36 .

[0147] On the other hand, Fig.8D It can be seen that the value of the second radius R2 changes continuously from the first transverse plane P1 to the second transverse plane P2, so that the difference between the second radius R2 and the fourth radius R4 has a zero value from the leading edge 41 to the third transverse plane P3 located between the first transverse plane P1 and the second transverse plane P2, and then the difference continuously increases from the zero value in the third transverse plane P3 to the maximum value h / 2 in the fourth transverse plane P4 located between the third transverse plane P3 and the second transverse plane P2, and then the difference continuously decreases from the maximum value h / 2 in the fourth transverse plane P4 to the zero value in the second transverse plane P2.

[0148] The third transverse plane P3 is defined as a transverse plane passing through the point of the fourth joint line 54 where the curvature of the fourth joint line 54 (and thus the outer arc surface 44 ) is greatest.

[0149] In this way, the third transverse plane P3 is located in a zone where impacts may occur due to the high speed of the gas stream.

[0150] Symmetrically, the third radius R3 has a constant value from the leading edge 41 to the trailing edge 42 of the profiled part 36 , which is equal to the value of the fourth radius R4 .

[0151] On the other hand, Fig. 8E It can be seen that the second radius R2 has a value that varies continuously from the leading edge 41 to the trailing edge 42, so that in any transverse plane, 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.

[0152] Thus, the difference between the second radius R2 and the fourth radius R4 has a maximum value h / 2 in the fourth transverse plane P4.

[0153] Likewise, the difference between the third radius R3 and the first radius R1 also has a maximum value h / 2 in the fourth transverse plane P4.

[0154] Thus, in this fourth transverse plane P4 , the difference between the second radius R2 and the first radius R1 is h.

Claims

1. A guide vane (33) intended to be fixed to a stator shroud (32) of a gas turbine engine (1), the guide vane comprising: a shaped part (36) intended to extend into the gas flow in order to guide said gas flow, said shaped part (36) having an inner arc surface (43) and an outer arc surface (44), and a platform (34) having a guide surface (45), a first side surface (46) and a second side surface (47), the shaped part (36) extending from the guide surface, the second side surface (47) being able to be arranged facing the first side surface (46) of the same adjacent guide vane, so that the platform (34) of the guide vane (33) and the platform of the adjacent guide vane define a flow path for the gas flow, the gas flow flowing between the shaped part (36) of the guide vane (33) and the shaped part of the adjacent guide vane, The guide surface (45) includes a first guide surface portion (48) and a second guide surface portion (49), the first guide surface portion extending from the inner arc surface (43) of the molding component (36) to the first side surface (46), and the second guide surface portion extending from the outer arc surface (44) of the molding component (36) to the second side surface (47), wherein a first joining line (51) is formed at an intersection between the first guide surface portion (48) and the first side surface (46), a second joining line (52) is formed at an intersection between the second guide surface portion (49) and the second side surface (47), a third joining line (53) is formed at an intersection between the first guide surface portion (48) and the inner arc surface (43), and a fourth joining line (54) is formed at an intersection between the second guide surface portion (49) and the outer arc surface (44), The first guide surface portion (48) and the second guide surface portion (49) are configured such that when the guide vane (33) is fixed to the shroud (32), the first joint line (51) has a first radius (R1) measured from the central axis (Δ) of the shroud (32) in a plane transverse to the central axis, the second joint line (52) has a second radius (R2) measured from the central axis (Δ) in the plane transverse to the central axis, the second radius (R2) is greater than the first radius (R1), the third joint line (53) has a third radius (R3) measured from the central axis (Δ) in the plane transverse to the central axis, and the fourth joint line (54) has a fourth radius (R4) measured from the central axis (Δ) in the plane transverse to the central axis, the fourth radius (R4) is less than or equal to the third radius (R3).

2. The 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 smaller than the third radius (R3).

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

4. The guide vane (33) according to claim 1, wherein: The fourth radius (R4) is equal to the third radius (R3).

5. The 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. The guide vane (33) according to any one of claims 1 to 5, wherein: The molding part (36) has a leading edge (41) and a trailing edge (42), 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 joining line (51) extending from the first transverse plane (P1) to the second transverse plane (P2), and the second joining line (52) extending from the first transverse plane (P1) to the second transverse plane (P2), and wherein, The difference between the second radius (R2) and the first radius (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 the difference increases continuously from the zero value in the third transverse plane (P3) to a maximum value in a fourth transverse plane (P4) located between the third transverse plane (P3) and the second transverse plane (P2), and then the difference decreases continuously from the maximum value in the fourth transverse plane (P4) to the zero value in the second transverse plane (P2).

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

8. The guide vane (33) according to claim 6 or 7, wherein: The first joining line (51) has a first radius (R1) having a constant value from the first transverse plane (P1) to the second transverse plane (P2).

9. The guide vane (33) according to claim 6 or 7, wherein: The first joining line (51) has a first radius (R1), which has a constant value from the first transverse plane (P1) to the third transverse plane (P3), then continuously decreases from the third transverse plane (P3) to the fourth transverse plane (P4), and continuously increases from the fourth transverse plane (P4) to the second transverse plane (P2).

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

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

12. A gas turbine engine assembly (30), the gas turbine engine assembly comprising: - a shield (32) having a central axis (Δ), - a set of guide blades (33) comprising a plurality of guide blades, Each guide vane (33) comprises a platform (34) and a shaped part (36), the platform having a guide surface (45), the shaped part extending radially from the guide surface (45) of the platform, the shaped part (36) having an inner arc surface (43) and an outer arc surface (44), and the platform (34) having a first side surface (46) and a second side surface (47), the guide surface (45) of the platform comprising a first guide surface portion (48) and a second guide surface portion (49), the first guide surface portion extending from the inner arc surface (43) of the shaped part (36) to the first side surface (46), the second guide surface portion extending from the outer arc surface (44) of the shaped part (36) to the second side surface (47), The guide vanes (33) are fixed to the shroud (32) so that the second side surface (47) of each guide vane (33) is arranged to face the first side surface (46) of an adjacent guide vane in the set of guide vanes, the first guide surface portion (48) and the second guide surface portion (49) of the platform (34) define a flow path for a gas flow flowing between the shaped parts (36) of the guide vanes, wherein each guide vane (33) has a first joining line (51), a second joining line (52), a third joining line (53) and a fourth joining line (54), the first joining line being formed at the intersection between the first guide surface portion (48) and the first side surface (46), the second joining line being formed at the intersection between the second guide surface portion (49) and the second side surface (47), the third joining line being formed at the intersection between the first guide surface portion (48) and the inner arc surface (43), and the fourth joining line being formed at the intersection between the second guide surface portion (49) and the outer arc surface (44), And wherein the first joining line (51) has a first radius (R1) measured from the center axis (Δ) in a plane transverse to the center axis, the second joining line (52) has a second radius (R2) measured from the center axis (Δ) in the plane transverse to the center axis, the second radius (R2) is greater than the first radius (R1), so that a portion of the second side surface (47) extends into the gas flow by forming a wall that prevents a portion of the gas flow from parasitically flowing from the inner arc surface (43) of the guide vane (33A) to the outer arc surface (44) of the adjacent guide vane (33B), the third joining line (53) has a third radius (R3) measured from the center axis (Δ) in the plane transverse to the center axis, and the fourth joining line (54) has a fourth radius (R4) measured from the center axis (Δ) in the plane transverse to the center axis, the fourth radius (R4) is less than or equal to the third radius (R3).

13. The assembly (30) according to claim 12, wherein: Each guide vane (33) complies with any one of claims 2 to 11.

14. Assembly (30) according to claim 12 or 13, wherein: The guide vanes (33) of the set of guide vanes are identical to each other.

15. Assembly (30) according to any one of claims 12 to 14, wherein: The shroud is an inner straightener shroud (31), and the guide surface of the platform of the guide vane (33) forms an inner wall of a gas flow duct.

16. The assembly (30) according to any one of claims 12 to 14, wherein: The shroud is an outer straightener shroud (32), and the guide surface of the platform (34) of the guide vane (33) forms an outer wall of a gas stream flow duct.

17. The assembly (30) according to any one of claims 12 to 16, wherein: The assembly is a compressor stator straightener assembly or a turbine stator straightener assembly or a fan straightener assembly.

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

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