Guide vane assembly for a low-pressure compressor of a turbine engine

Abstract

The invention relates to a guide vane assembly (10) for a low-pressure compressor of an aircraft turbine engine, the assembly extending around a longitudinal axis and comprising an air flow path delimited by a wall (91, 92), and a plurality of variable-pitch blades (20) about an axis of rotation (R) and which extend in this air flow, each of the blades (20) being continued by a shaft (31, 32) which extends along the axis of rotation (R) and which is pivotably mounted in a portion (915, 925) of the wall (91, 92). The portion (915, 925) is made of a non-metallic material and the shaft (31, 32) is inserted into a non-metallic element (81, 82) which is integrated into the portion (915, 925) such that the clearance between the shaft (31, 32) and the portion (915, 925) is minimised.

Description

Description Title: Rectifier assembly for low-pressure turbomachine compressor

[0001] In a turbomachine, for example a twin-spool, twin-flow turbomachine extending along a longitudinal axis, an upstream compressor compresses the air that enters the turbomachine from the upstream end. This air is admitted into a duct and then into the turbomachine's combustion chamber located downstream of this duct, where it is mixed with fuel before being burned. The hot gases from this combustion are then expanded into a turbine located downstream of this chamber, driving the turbine's rotation. The turbine's rotation drives a shaft of the turbomachine on which the turbine is mounted. This shaft, in turn, drives the compressor and the fan blades located upstream of the turbomachine. The rotation of the fan blades, along with the high-speed ejection of gases from the combustion chamber, contributes to the turbomachine's propulsion.

[0002] The compressor consists of a low-pressure compressor and a high-pressure compressor. Each low-pressure and high-pressure compressor comprises a plurality of coaxial stages, each stage including a stator or vane stator that is fixed relative to the turbomachine's axis and a vane rotor that rotates about this axis. The stator and rotor are each a disc with vanes on their outer periphery. These vanes are evenly distributed around this outer periphery and are located in the airflow stream. The stator includes variable stator vanes, also called variable stator vanes (VSVs), mounted on one or more of the discs. The variable stator vanes occupy different angular pitch positions.

[0003] Figure 7 illustrates such a variable-pitch blade 120 of a low-pressure compressor rectifier assembly, in an exploded perspective view. This blade 120 is mounted in the groove which is delimited by an annular inner wall 191 and an annular outer wall 192 (shown schematically in dashed lines). The blade 120 extends radially via a shaft An internal shaft 131 and a radially external shaft 132 extend along a radial axis R that is perpendicular to the longitudinal axis of the turbomachine. An internal plate 141 is located between the internal shaft 131 and the blade 120. An external plate 142 is located between the external shaft 132 and the blade 120. The internal shaft 131 is housed in an opening in the internal wall 191. The external shaft 132 is housed in an opening in the external wall 192.

[0004] Thus, we know of a rectifier assembly for a low-pressure turbomachine aircraft compressor, the assembly extending around a longitudinal axis and comprising an airflow channel delimited by a wall, a plurality of blades with variable pitch around an axis of rotation which extend in this airflow, each of the blades extending by a shaft which extends along the axis of rotation and which is pivotally mounted in a portion of the wall.

[0005] The fig is a cross-sectional view in plane VIII-VIII of the figure which is a radial plane containing the axis of rotation R. The internal shaft 131 is housed in a sleeve 180 which is inserted into the opening of the portion 1915, thus facilitating the pivoting of the blade 120 relative to the duct. The arrangement is similar for the external shaft 132, which is housed in a sleeve 180 inserted into the opening of the portion 1925. During operation, undesirable vibrations of the blade 120 and wear are observed at the connection between the internal shaft 131 and the portion 1915 of the duct and / or at the connection between the external shaft 132 and the portion 1925 of the duct. This is also the case when the 180 socket is crimped into the portion (1915, 1925) or onto the shaft (131, 132) because the crimping operation generally involves using a 180 socket with increased dimensions to avoid seizing. Description of the invention

[0006] The present invention aims to remedy these drawbacks.

[0007] The invention aims to provide a rectifier assembly for low pressure compressors in which vibrations and wear at the level of the connections between the steerable blades and the wall of the vein are minimized.

[0008] This goal is achieved because the portion of the wall is made of a non-metallic material and the tree is inserted into a non-metallic element. which is integrated into the portion in such a way that the gap between the tree and the portion is minimized.

[0009] Thanks to these features, the shaft carrying the blade rotates directly relative to the (portion of) wall, without a bushing or other intermediate part. Furthermore, the wall portion is made of a non-metallic material, which facilitates the integration of the element in which the shaft pivots. This optimizes the manufacturing of the assembly. The clearance between the shaft and the wall is also minimized, which reduces vibration and wear between the blade and the wall. Moreover, this clearance is better controlled during operation because differential thermal expansion between the shaft and the wall is minimized.

[0010] For example, the element is manufactured by co-molding or bi-injection with the portion or by overmolding into the portion.

[0011] For example, the element is a part of the portion.

[0012] For example, the element is made of a material that wears preferentially to the material forming the shaft.

[0013] For example, the material of the portion of the wall is a polymer matrix composite with reinforcement.

[0014] For example, the V1 vein has a conformation in which the distance between one end of each of the blades and the portion is constant regardless of the angular position of the blade around its axis of rotation R.

[0015] For example, the wall includes an inner ferrule that radially delimits the V1 vein internally and an outer ferrule that radially delimits the V1 vein externally, and the shaft includes an inner shaft and an outer shaft, each of the blades extending radially internally by the inner shaft which is pivotally mounted in the portion of the inner ferrule and radially externally by the outer shaft which is pivotally mounted in the portion of the outer ferrule.

[0016] The invention also relates to a method for manufacturing a rectifier assembly for a low-pressure compressor of an aircraft turbomachine, the assembly extending around a longitudinal axis X and comprising a V1 channel of air flow delimited by a wall, a plurality of blades with variable pitch around an axis of rotation R and which extend into the air flow, each of the blades extending by a shaft which extends along the axis of rotation R and which is pivotally mounted in a portion of the wall.

[0017] According to the invention, the process comprises the following steps (a) The portion is made of a non-metallic material and a non-metallic element is integrated into the portion; (b) The tree is inserted into the element in such a way that the gap between the tree and the portion is minimized.

[0018] The invention will be better understood and its advantages will become more apparent upon reading the following detailed description of embodiments shown by way of non-limiting examples. The description refers to the accompanying drawings in which:

[0019] [Fig. 1] Figure 1 is a longitudinal view of an aircraft turbomachine.

[0020] [Fig. 2] Figure 2 is a perspective view of a rectifier assembly for a low-pressure compressor of an aircraft turbomachine according to a first embodiment.

[0021] [Fig. 3] Figure 3 is a cross-sectional view along plane lll-lll of figure 2.

[0022] [Fig. 4] Figure 4 is a view of a blade of an assembly according to the invention in a plane perpendicular to the axis of rotation R of this blade.

[0023] [Fig. 5] Figure 5 is a perspective view of a rectifier assembly for a low-pressure compressor of an aircraft turbomachine according to a second embodiment.

[0024] [Fig. 6] Figure 6 is a cross-sectional view along plane VI-VI of Figure 5.

[0025] [Fig. 7] Figure 7, already described, is an exploded perspective view of a rectifier assembly for a low-pressure compressor of an aircraft turbomachine according to the prior art.

[0026] [Fig. 8] Figure 8, already described, is a cross-sectional view along plane VIII-VIII of figure 7. Detailed description of the invention

[0027] Consider a turbomachine 1 with longitudinal axis X, which is its axis of rotation. In the description below, the terms "internal" and "inside" refer to an element oriented towards the longitudinal axis X or located closer to it. The terms "external" and "outside" refer to an element oriented in the opposite direction to the longitudinal axis X or located further from it. The terms "upstream" and "downstream" are relative to the direction of air and gas flow during the operation of the turbomachine, i.e., from left to right in the figures. The term "radial" refers to a position or direction in a transverse plane perpendicular to the longitudinal axis X.

[0028] By way of example, the invention is described in the case where the turbomachine 1 is a twin-spool, twin-flow turbomachine. However, the invention applies to any turbomachine, including a RISE-type turbomachine with a third internal flow.

[0029] Figure 1 illustrates a twin-spool, twin-flow turbomachine 1, in longitudinal view. This turbomachine 1 comprises a nacelle 2 with a fan 3 having blades. The turbomachine 1 has a hub 8m, one rotor element of which carries the ring of blades forming the fan's propeller 3. The hub 8m consists of alternating rotor and stator elements along the longitudinal axis X. These rotor elements of the hub 8m are supported by a rotor shaft 8 extending along the longitudinal axis X. Radially outside the hub 8m and downstream of the fan's propeller 3 is an internal casing 9, which is coaxial with the hub 8m.

[0030] In normal operation of the turbomachine 1, an airflow (called secondary flow F2) circulates in an annular channel, called the second channel V2, which extends between the inner casing 9 and the nacelle 2. Another annular channel, called the first channel V1 or channel V1, extends between the hub 8m and the inner casing 9. The first channel V1 includes downstream of the blower 3 a compressor 4 and a combustion chamber 5. This compressor 4 includes upstream a low-pressure compressor 4a and downstream a high-pressure compressor 4b. The air compressed by the compressor 4 is admitted downstream into the combustion chamber 5 and mixed with fuel before being burned there.

[0031] The hot gases from this combustion are then expanded in a turbine in the first flow V1, causing the turbine to rotate. This turbine comprises a high-pressure turbine 6 located downstream of the combustion chamber 5, and a low-pressure turbine 7 located downstream of the high-pressure turbine 6. The movable turbine blades of the high-pressure turbine 6 and the low-pressure turbine 7 are mounted on discs that are mounted on the rotor shaft 8, and which therefore drive the rotor shaft 8 in rotation. The rotor shaft 8 drives the rotor elements of the hub 8m and the fan 3. The rotation of the fan 3, along with the high-speed ejection of gases from the combustion chamber 5, contributes to the propulsion of the turbomachine 1.

[0032] The low-pressure compressor 4a and the high-pressure compressor 4b comprise a plurality of coaxial stages E, each stage including a stator or bladed stator Ds connected to the stator elements of the hub 8m and a bladed rotor DR connected to the rotor elements of the hub 8m, which are driven in rotation by the rotor shaft 8. The stator Ds and the rotor DR are each a disk carrying these blades on their outer periphery. These blades are regularly distributed on this outer periphery such that each blade extends radially outward from the disk in the first groove V1.

[0033] For example, the rotor shaft 8 comprises a first rotor shaft that drives the low-pressure compressor 4a and a second rotor shaft that drives the high-pressure compressor 4b. The blower 3 is mounted directly on the first rotor shaft. Alternatively, the blower 3 is connected to a gearbox that is driven by the first rotor shaft.

[0034] The stator Ds of the 4a low-pressure compressor includes adjustable vanes 20, also known as variable-pitch vanes. These vanes 20 are mounted on one or more of the discs. The adjustable vanes 20 occupy different angular pitch positions.

[0035] Consider a rectifier assembly 10 for the low-pressure compressor 4a. This assembly 10 extends around the longitudinal axis X and comprises the airflow channel V1 delimited by a wall (91, 92), and a plurality of blades 20 with variable pitch about an axis of rotation R, extending into this airflow. The axis of rotation R is perpendicular to the longitudinal axis X of the turbomachine 1, and is therefore radial. Each of the blades 20 extends into a shaft (31, 32) that extends along the axis of rotation R and is pivotally mounted in a portion (915, 925) of the wall (91, 92). The shaft (31, 32) is inserted into an element (81, 82) that is integrated into the portion (915, 925). By "integrated" we mean that the element (81, 82) is not dissociated from the portion (915, 925).This solution covers the case where the element (81, 82) is manufactured by molding with the portion (915, 925) (see first embodiment described below), and the case where the element (81, 82) is a part / region of the portion (915, 925) (see second embodiment described below). This solution therefore excludes the case where the element (81, 82) is attached to the portion (915, 925) after the wall (91, 92) has been manufactured, for example, the case where the element (81, 82) is a socket that is inserted into a hole in the portion (915, 925). In other words, the element (81, 82) has an opening into which the shaft (31, 32) is inserted and relative to which this shaft (31, 32) is able to pivot. Thus, the shaft (31, 32) is directly connected via a pivot joint to the portion (915, 925) of the wall (91, 92), without a bushing or other intermediate part between the shaft (31, 32) and the wall (91, 92). The clearance between the shaft (31, 32) and the wall (91, 92) is therefore minimized.The assembly of the blades 20 is also simplified because the number of parts is reduced. In addition, the portion (915, 925) (for example the entire wall (91, 92)) is made of a non-metallic material, which facilitates the integration into the portion (915, 925) of the element (81, 82) in which the shaft pivots (31, 32), which helps to minimize vibration and wear between the blade and the wall.

[0036] For example, the V1 vein is annular and extends between a radially internal wall 91 with a portion 915 and an internal element 81, and a radially external wall 92 with a portion 925 and an external element 82. This blade 20 is mounted in the V1 vein and extends via a radially internal shaft 31 and a radially external shaft 32, which extend along the radial axis R. A plate An internal 41 is located between the internal shaft 31 and the blade 20. An external plate 42 is located between the external shaft 32 and the blade 20. The internal shaft 31 is housed in an opening in a portion 915 of the internal wall 91. The external shaft 32 is housed in an opening in the external wall 92.

[0037] In a first embodiment, the element (81, 82) is manufactured by co-molding or bi-injection with the portion (915, 925) or by overmolding into the portion (915, 925). This embodiment is illustrated in Figures 2 and 3. Figure 2 is a perspective view of the blade 20 mounted in the wall 91. Figure 3 is a cross-sectional view in the lll-lll plane of the which is a radial plane containing the axis of rotation R. The wall 92 is schematically represented by dashed lines. The element (81, 82) is, for example, made of ceramic, polymer, or polymer matrix composite with reinforcement, for example, fibrous reinforcement. The fibers are, for example, woven. The portion (915, 925) is, for example, made of ceramic, polymer, or polymer matrix composite. The element (81, 82) is made of a material distinct from the portion (915, 925). This embodiment allows for the selection of an element (81, 82) dimensioned such that the clearance between this element (81, 82) and the shaft (31, 32) is minimized. The internal shaft 31 and the internal element 81 are concealed beneath the internal ferrule 91 in Figure 2, and the internal element 82 is omitted.

[0038] Figure 4 is a view of the blade 20 and portion 915 of the inner wall 91 in a plane perpendicular to the axis of rotation R. It is a top view of the blade 20, looking towards the longitudinal axis X of the turbomachine 1, which is perpendicular to the axis of rotation R and is indicated in this figure. This view shows the shaped region of portion 915 such that the distance D between the radial end of the blades 20 opposite the inner wall 91 of the flow V1 is constant regardless of the angular position of the blades (see explanations below).

[0039] In a second embodiment, the element (81, 82) is part of the portion (915, 925), that is, the element (81, 82) is a region of the portion (915, 925) and is therefore made of the same material as the portion (915, 925). The portion (915, 925) is, for example, made of ceramic, polymer, or polymer matrix composite. This embodiment is illustrated in Figures 5 and 6. Figure 5 is a perspective view of the turbine blade 20 mounted in the wall 91. Figure 6 is a cross-sectional view in plane VI-VI of fig. which is a radial plane containing the axis of rotation R. The outer wall 92 is schematically represented by dashed lines. This embodiment allows the portion (915, 925) to be dimensioned such that the clearance between the element (81, 82) and the shaft (31, 32) is minimized. The internal shaft 31 and the internal element 81 are hidden under the internal ferrule 91 in Figure 5, and the internal element 82 is omitted.

[0040] Advantageously, in the first or second embodiment, the element (81, 82) is made of a material that wears preferentially to the material forming the shaft (31, 32). For example, the hardness of the element (81, 82) is lower than the hardness of the material forming the shaft (31, 32), which minimizes wear on the shaft (31, 32).

[0041] Advantageously, in the first or second embodiment, the material of the element (81, 82) and the material of the shaft (31, 32) have a low coefficient of dynamic friction, for example, less than 0.3, less than 0.2, or less than 0.1. The coefficient of dynamic friction (pd) between two surfaces is the ratio of the friction force to the normal force on the surfaces as they move relative to each other. The risk of seizing between the element (81, 82) and the shaft (31, 32) is thus minimized.

[0042] In all embodiments, when portion (915, 925) of the wall (91, 92), and possibly the entire wall (91, 92), is made of polymer or a polymer matrix composite material reinforced with fibers or particles, the wall (91, 92) is manufactured less expensively than a metallic wall. Furthermore, a reduction in the engine's mass is achieved, leading to improved overall performance. The use of polymers is feasible in the case of a low-pressure compressor, where the temperature is sufficiently low, unlike in a high-pressure compressor. For example, the polymer could be a polyimide. Alternatively, portion (915, 925) could be made of ceramic, reinforced or unreinforced.

[0043] Figures 2 to 6 illustrate only the mounting of the blade 20 in the inner wall 91. However, the situation is similar for the mounting of the blade 20 in the outer wall 92.

[0044] In a third embodiment, which can be combined with the first or second embodiment above, the wall (91, 92) comprises an inner ferrule 91 that radially delimits the internal flow V1 and an outer ferrule 92 that radially delimits the external flow V1. The shaft (31, 32) comprises an inner shaft 31 and an outer shaft 32, each of the blades 20 extending radially inwardly by the inner shaft 31, which is pivotally mounted in a portion 915 of the inner ferrule 91, and radially outwardly by the outer shaft 32, which is pivotally mounted in a portion 925 of the outer ferrule 92. The inner shaft 31 (respectively, outer shaft 32) is inserted into an inner element 81 (respectively, outer element 82) that is integrated into the portion 915 (respectively, portion 925).

[0045] The outer ferrule 92 can be an annular ferrule or a half-shell ferrule. The inner ferrule can be a two-part annular ferrule (upstream and downstream) or a sectored ferrule with abradable ring assembly. The diameter of the inner ferrule 91 can range from 200 mm to 1400 mm, for example, from 400 mm to 1200 mm. The inner ferrule 91 can have a length of less than 600 mm, for example, from 150 mm to 600 mm. A VSV blade stage E can have up to 120 blades.

[0046] As indicated above, the blade 20 assumes several angular positions by pivoting around the radial axis of rotation R, which are illustrated in Fig. The angular positioning of the blades 20 is controlled by a variable positioning system (not shown). Depending on the angular positioning occupied by the blade 20 by pivoting around the internal shaft 31, significant play may exist between the blades 20 and the internal wall 91 and / or the external wall 92 forming the flow channel. Such play can be detrimental to airflow and compressor performance.

[0047] To solve this problem, the inner wall 91 and / or the outer wall 92 are shaped such that the distance D between the radial end of the blades 20 opposite the inner wall 91 and / or the outer wall 92 of vein V1 is constant regardless of the angular position of the blades. This distance is measured along the radial axis R. The radial end of the blades 20 opposite the wall (915, 925) is a portion of the blade 20 that extends beyond the plate (41, 42). It is the portion 915 (respectively 925) of the inner wall 91 (respectively outer wall 92) that faces the radial end of the blade 20 and is thus shaped to reduce the clearance between the blade 20 and the wall (91, 92) during turbomachine operation. The clearance D also takes into account the tolerance chains to prevent contact between the blade 20 and the wall (91, 92). The distance / clearance D is referenced in Figures 3 and 6 and is illustrated in a zoom of the space between portion 915 and the radially internal end of blade 20. Figures 2, 3, 5 and 6 show the conformation of the region of portion 915 which is swept by the radially internal end of blade 20.The shaped region of portion 915 is also visible in Figure 4. The arrangement is similar with regard to the shaping of portion 925 of the outer wall 92 which is swept by the radially outer end of the blade 20. Advantageously, the distance D is minimized, for example less than 5 mm, for example less than 1 mm, which allows a compromise between the quality of the airflow in the vein V1 and the mounting clearance of the blades.

[0048] This internal wall conformation 91 and / or external wall 92 corresponds to a fourth embodiment, which can be combined with the first, second, or third embodiment above. The wall conformation (91, 92) can be concave or convex, and can be achieved by material removal (machining) or addition (for example, by additive manufacturing). The conformation can also be achieved by molding or injection, as permitted by polymer or fibrous polymer matrix composite materials.

[0049] The invention also relates to a method for manufacturing a rectifier assembly 10 as described above, wherein each of the portions (915, 925) is manufactured from a non-metallic material and a corresponding non-metallic element (81, 82) is integrated into each of these portions (915, 925) (step (a)), and further wherein a shaft (31, 32) of the blade 20 is inserted into each of these elements (81, 82) such that the clearance between each of these shafts (31, 32) and these corresponding portions (915, 925) is minimized. For example, the elements (81, 82) are manufactured by co-molding or bi-injection with the corresponding portion (915, 925), or by overmolding in this portion (915, 925). Alternatively, the elements (81, 82) are a part of the corresponding portion (915, 925), that is to say, a region of this portion (915, 925) constitutes the corresponding element (81, 82).

Claims

Demands

1. A low-pressure turbomachinery compressor (10) assembly for a low-pressure aircraft turbomachine, the assembly extending about a longitudinal axis (X) and comprising an airflow channel (V1) delimited by a wall (91, 92), a plurality of blades (20) with variable pitch about an axis of rotation (R) and extending into said airflow, each of said blades (20) extending into a shaft (31, 32) extending along said axis of rotation (R) and pivotally mounted in a portion (915, 925) of said wall (91, 92), said assembly being characterized in that said portion (915, 925) is made of a non-metallic material and in that said shaft (31, 32) is inserted into a non-metallic element (81, 82) which is integrated into said portion (915, 925) in such a way that the play between said tree (31, 32) and said portion (915, 925) is minimized.

2. Assembly (10) straightener according to claim 1 such that said element (81, 82) is manufactured by co-molding or bi-injection with said portion (915, 925) or by overmolding in said portion (915, 925).

3. Rectifier assembly (10) according to claim 1 such that said element (81, 82) is a part of said portion (915, 925).

4. Rectifier assembly (10) according to any one of claims 1 to 3 wherein said element (81, 82) is made of a material which wears preferentially to the material forming said shaft (31, 32).

5. Assembly (10) straightener according to any one of claims 1 to 4 wherein the material of said portion (915, 925) of the wall (91, 92) is a polymer or ceramic matrix composite with reinforcement.

6. Assembly (10) straightener according to any one of the preceding claims such that said vein (V1) has a conformation in which the distance between an end (21, 22) of each of said blades (20) and said portion (915, 925) is constant regardless of the angular position of said blade (20) around said axis of rotation (R).

7. Assembly (10) straightener according to any one of the preceding claims such that said wall (91, 92) comprises a ferrule internal (91) which radially delimits internally said vein (V1) and an external ferrule (92) which radially delimits externally said vein (V1), and said shaft (31, 32) comprises an internal shaft (31) and an external shaft (32), each of said blades (20) extending radially internally by said internal shaft (31) which is pivotally mounted in said portion (915) of the internal ferrule (91) and radially externally by said external shaft (32) which is pivotally mounted in said portion (925) of the external ferrule (92).

8. Assembly (10) according to claim 7 such that said ferrules (91, 92) are half-shell ferrules, annular ferrules, or sectorized ferrules.

9. Turbomachine comprising an assembly (10) according to any one of claims 1 to 8.

10. A method for manufacturing a low-pressure turbomachinery compressor (10) rectifier assembly for aircraft, the assembly extending about a longitudinal axis (X) and comprising an airflow channel (V1) delimited by a wall (91, 92), a plurality of blades (20) with variable pitch about an axis of rotation (R) and extending into said airflow, each of said blades (20) extending into a shaft (31, 32) extending along said axis of rotation (R) and pivotally mounted in a portion (915, 925) of said wall (91, 92), said method comprising the following steps: (a) Said portion (915, 925) is made of a non-metallic material and a non-metallic element (81, 82) is integrated into said portion (915, 925); (b) We insert said tree (31, 32) into said element (81, 82) in such a way that the gap between said tree (31, 32) and said portion (915, 925) is minimized.

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