Method for manufacturing a turbine blade from ceramic matrix composite material

Abstract

Method for manufacturing a turbine blade from ceramic matrix composite material. The present invention relates to a method for manufacturing a turbine blade from CMC, comprising: - providing a first texture (10) defining a blade reinforcement and a blade root reinforcement, - providing a pair of second textures (20), each having, in the blade region, at least one assembly portion (26) cut out and deployable relative to the rest of the second texture so as to define a notch (40), - assembling the second fibrous textures with the first fibrous texture by positioning each deployed assembly portion against the first texture and positioning the first texture in the notches of the second textures, and - bonding the first texture with the second textures, after assembly, by co-densification with a common ceramic matrix. Fig. 6.

Description

Title of the invention: Method for manufacturing a turbine blade from a ceramic matrix composite material. Technical field

[0001] The present exposition relates to the general field of the design of turbine blades made of ceramic matrix composite (CMC) material. Previous technique

[0002] Ceramic matrix composite materials (CMCs) withstand temperatures ranging from 600°C to 1400°C. Due to their superior high-temperature resistance, CMCs require less cooling. Since this cooling is traditionally obtained from the compressor, which impacts the turbomachine's efficiency, CMCs improve engine efficiency, thereby reducing fuel consumption. Furthermore, their use helps optimize turbomachine performance, notably by reducing the overall mass of the turbomachine, which further contributes to lower fuel consumption and thus a significant reduction in pollutant emissions.

[0003] Turbine blades made of CMC material can be produced from a fibrous blank obtained by three-dimensional weaving, which is then shaped and densified by the ceramic matrix. Functional parts, such as the platform, can be formed by unfolding and shaping woven portions separated from the rest of the fabric. However, weaving can be relatively complicated for a blank comprising both the structural part and the functional parts, which may have complex shapes. Furthermore, producing spoilers by weaving them in a single piece with the other parts of the blade can result in a woven width significantly greater than that required for the main preform (foot, strut, and blade), and therefore substantial textile waste, thus increasing the cost of the process and hindering its industrialization. The invention aims to overcome these drawbacks. Description of the invention

[0004] The present description relates to a method for manufacturing a turbine blade made of ceramic matrix composite material, comprising: - the provision of a first fibrous texture comprising a first region intended to define a reinforcement of a blade and a second region intended to define a reinforcement of a foot of the blade to be obtained, - the provision of a pair of second fibrous textures, each having, in succession along an axial direction, an upstream end region, a blade region and a downstream end region, each second texture having, in the region of blade, at least one cut assembly portion, formed by an upstream cut and a downstream cut each transverse to the axial direction, and located on the side of a tangential assembly edge, said at least one assembly portion being capable of being deployed relative to the rest of the second texture so as to define, in the blade region on the side of the assembly edge, a notch upon its deployment, - the assembly of the second fibrous textures with the first fibrous texture by positioning the tangential assembly edge of each second texture on a respective intrados or extrados side of the first texture, by positioning each deployed assembly portion against the first texture and by positioning the first texture in the notches of the second textures, the parts of the blade regions opposite the tangential assembly edge being intended to define a platform reinforcement of the blade to be obtained, and the second textures being intended to define,on the upstream and downstream end regions, at least one reinforcement of the dawn spoilers to be obtained, and, - a bonding of the first texture with the second textures, after assembly, by co-densification by a common ceramic matrix.

[0005] The invention proposes manufacturing a blade using complementary fibrous textures prepared separately. This greatly simplifies the fabrication of the reinforcement and allows for a high degree of complexity in the designs of the functional parts defined by the second textures, thus best adapting to the requirements while maintaining controlled production costs. The invention also makes it possible to limit the width of the woven blade compared to a single-texture blade. The deployment of the assembly portions allows for the formation of connecting radii with the first texture and provides a stronger bond than if the assembly were only ensured on the edges of the second textures.This assembly method avoids, in particular, the deployment of a stub from the first texture used as a base for the second textures, and allows the positioning of the platform, spoilers and any low walls to be adjusted independently of positioning errors on the first texture.

[0006] In one embodiment, at least one of the second fibrous textures is formed by three-dimensional weaving and comprises two cut assembly portions formed by unbound fibrous skins not woven together on an unbound zone, the assembly portions being deployed in opposite directions to be positioned against the first texture during assembly.

[0007] Such a feature helps to further improve the robustness of the link between the first and second textures.

[0008] In particular, each second texture can be formed by three-dimensional weaving and can comprise two cut assembly portions formed by skins unbound fibrous non-woven fibers joined together on an unbound zone, the assembly portions of each second texture being able to be deployed in opposite directions to be positioned against the first texture during assembly.

[0009] Such a feature helps to further improve the robustness of the link between the first and second textures.

[0010] In one embodiment, the second textures assembled with the first texture define, on at least one of the upstream and downstream end regions, a foldable part intended to form the reinforcement of a wall, and the method further includes, after assembly and before joining, folding the foldable part onto the first texture so as to define a preform of the wall.

[0011] Such a feature helps to further functionalize the dawn by integrating into the second textures a reinforcement of an upstream wall and / or a downstream wall.

[0012] In particular, the second textures assembled to the first texture can define, on each of the upstream and downstream end regions, a foldable part intended to form the reinforcement of a wall, and the method can further include, after assembly and before joining, folding each foldable part onto the first texture so as to define an upstream wall preform and a downstream wall preform.

[0013] Such a feature helps to further functionalize the dawn by integrating into the second textures a reinforcement of an upstream wall and a downstream wall.

[0014] In one embodiment, the second textures are in partial overlap on the upstream and downstream end regions.

[0015] Such a characteristic helps to improve the mechanical strength of the spoilers, and possible walls, which correspond to areas subjected to mechanical stress, and ensures continuity between the intrados and extrados.

[0016] In one embodiment, the first texture is formed by three-dimensional weaving.

[0017] In one embodiment, all or part of the common ceramic matrix is ​​formed by chemical vapor infiltration, with molten silicon or a molten silicon alloy infiltration optionally being carried out after the chemical vapor infiltration to finalize the common ceramic matrix.

[0018] The present description also relates to a fibrous assembly intended to form a reinforcement of a turbine blade made of ceramic matrix composite material, comprising: - a first fibrous texture comprising a first region intended to define a reinforcement of a blade and a second region intended to define a reinforcement of a blade root, and - a pair of second fibrous textures assembled with the first fibrous texture, the second textures each having, in succession along an axial direction, an upstream end region, a blade region and a downstream end region, each second texture having, in the blade region, at least one cut assembly portion, formed by an upstream cut and a downstream cut each transverse to the axial direction, and located on the side of a tangential assembly edge, said at least one assembly portion being deployed relative to the rest of the second texture so as to define, in the blade region on the side of the assembly edge, a notch, the tangential assembly edge of each second texture being positioned on a respective intrados or extrados side of the first texture, each deployed assembly portion being positioned against the first texture and the first texture being positioned in the notches of the second textures,The portions of the blade regions opposite the tangential assembly edge are intended to define a blade platform reinforcement, and the second textures are intended to define, on the upstream and downstream end regions, at least one blade spoiler reinforcement.

[0019] This assembly may correspond to the product obtained, after assembly or before codensification, by implementing the process described above.

[0020] In one embodiment, at least one of the second fibrous textures is formed by three-dimensional weaving and comprises two cut assembly portions formed by unbound fibrous skins not woven together on an unbound zone, the assembly portions being deployed in opposite directions and being positioned against the first texture.

[0021] In one embodiment, the second textures assembled with the first texture define, on at least one of the upstream and downstream end regions, a part folded over the first texture intended to define a preform of a wall.

[0022] In one embodiment, the second textures are in partial overlap on the upstream and downstream end regions.

[0023] The aforementioned features and advantages, as well as others, will become apparent from the detailed description that follows, which refers to the attached drawings. Brief description of the drawings

[0024] The attached drawings are schematic and are intended primarily to illustrate the principles of the exposition.

[0025] On these drawings, from one figure to another, identical elements (or parts of elements) are identified by the same reference signs. [Fig.1] The [Fig.1] is a schematic cross-sectional view of a turbofan engine. [Fig.2] Fig.2 represents, schematically, an example of a first fibrous texture usable within the framework of the invention. [Fig.3] Fig.3 schematically represents, in top view, an example of a second fibrous texture usable within the framework of the invention. [Fig.4] The [Fig.4] is a cross-sectional view, taken at level IV-IV, of the blade region of the second fibrous texture of the [Fig.3]. [Fig.5] Fig.5 represents, in top view, the second fibrous texture of Fig.3 in the configuration where the assembly portions are deployed. [Fig.6] Fig.6 schematically represents an example of assembly between the first texture according to Fig.2 and a pair of second textures according to Fig.3 which can be implemented within the framework of the invention. [Fig.7] Fig.7 schematically represents an assembly variant that can be implemented within the framework of the invention. [Fig.8] Fig.8 schematically represents another assembly variant that can be implemented within the framework of the invention. Description of the implementation methods

[0026] Figure 1 shows, in cross-section along a vertical plane passing through its principal axis A, a turbofan engine 1 as described above. It comprises, from upstream to downstream along the airflow path, a fan 2, a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6, and a low-pressure turbine 7.

[0027] The blower 2 allows the aspiration of an airflow to which two independent circulations are imposed, to form a primary airflow (hot flow) and a secondary airflow (cold flow).

[0028] The primary flow air can for example be compressed within the low pressure compressor 3 and then the high pressure compressor 4, and then mixed with a fuel and burned within a combustion chamber 5. The gases expelled from the combustion chamber can pass through the high pressure turbine 6 and then the low pressure turbine 7 before undergoing acceleration through a nozzle.

[0029] The secondary flow, on the other hand, bypasses the hot part of the reactor.

[0030] The compressors 3, 4 and the turbines 5, 6 comprise several stages of fixed blades (called "stators") and moving blades (called "rotors").

[0031] The movable blades comprise a ring of blades mounted radially on a disk, which drives a rotating shaft under the effect of a passing air or gas flow. Each blade comprises a blade connected to a foot that is fitted into a groove in the disk in order to hold the blade in place during the operation of the turbomachine.

[0032] The fixed blades, generally arranged between each stage of moving blades, allow the airflow to be straightened before the flow enters the next stage of moving blades.

[0033] In the present exposition, the terms "axial", "radial", "tangential", and their derivatives are defined with respect to the main axis of the turbomachine; the terms "upstream" and "downstream" are defined with respect to the airflow in the turbomachine.

[0034] Figure 2 illustrates, in isolation, a first fibrous texture 10 comprising a first region 30 intended to define a reinforcement for a blade and a second region 50 intended to define a reinforcement for a foot. The first texture 10 can be obtained in a single piece by three-dimensional weaving, using, for example, ceramic yarns, particularly silicon carbide (SiC). "Three-dimensional weaving" or "3D weaving" refers here to a weaving method in which at least some of the weft yarns bind warp yarns over several warp layers. It should be noted that a reversal of roles between warp and weft is possible and should be considered as also covered by the claims.

[0035] The first region 30 extends between a first end 30a located on the side of the second region 50 and a second end 30b at the apex. The first region 30 is shaped, in a manner known per se, so as to impart the desired shape to the aerodynamic profile of the blade. The first region 30 extends along a radial direction DR corresponding to the direction along a radius of the turbine ring (a straight line connecting the center of the turbine ring to its periphery). The first region 30 has a first edge 30c intended to form the leading edge and a second edge 30d intended to form the trailing edge, spaced along an axial direction DA corresponding to the flow direction of the gas stream in the duct. In an unillustrated embodiment, the first texture may include a third region intended to define all or part of the tail (including the flaps).

[0036] Figure 3 schematically represents, in top view, an example of a second fibrous texture 20 that can be implemented within the scope of the invention. Only one second fibrous texture is illustrated, it being understood that each of the second textures in the pair intended to be assembled with the first texture can have a similar structure. The description below can therefore be applied to each second texture forming this pair.

[0037] The second texture 20 has, successively along an axial direction DA, an upstream end region 22a, a blade region 24, and a downstream end region 22b. Unless otherwise stated, the terms "upstream" and "downstream" are used here with reference to the direction of gas flow in the vein. Regions 22a and 22b are in the textile continuity of region 24 and extend from it. In the illustrated example, the second texture 20 is made of a single piece of fabric.The three-dimensional structure features a debonding zone 25 in region 24. As is known, a debonding is achieved between two layers of warp yarns by preventing weft yarns from passing through the debonding zone, thus avoiding binding warp yarns located on either side of the debonding. Zone 25 extends in a plane containing the direction DA and a tangential direction DT. Zone 25 is formed within the thickness (radial dimension) of the second texture 20 and allows it to be separated, in region 24, into two unbound fibrous skins 26 that can be pulled apart. These skins 26 form the assembly portions, and their function will be further detailed later. Zone 25 extends over only part of the width LA20 (or tangential dimension) of the second texture 20, and over only part of the length LO20 (or axial dimension) of the second texture 20.Zone 25 is axially delimited by an upstream axial edge 23a and a downstream axial edge 23b. Zone 25 opens tangentially onto a tangential edge BT1, referred to as the tangential assembly edge, and is tangentially delimited on the side opposite edge BT1 by a debonding zone 27. Region 22a is located between an upstream axial edge BAI of the second texture 20 and the upstream axial edge 23a. In the example considered here, the second texture 20 does not have a tissue debonding zone in regions 22a and 22b, but this does not depart from the scope of the invention if it does otherwise, as will be described below in relation to [Fig. 7]. Region 22b is located between a downstream axial edge BA2 of the second texture 20 and the downstream axial edge 23b.In region 24, the skins 26 are woven together beyond the bottom 27 to form a part 28 located on the opposite side of the BT1 assembly edge (or on the side of the BT2 edge) and which is intended to define a blade platform reinforcement to be obtained, as will be described later. Part 28 is located between regions 22a and 22b.

[0038] The second texture 20 has an upstream cut 29a located on the side of the edge 23a (or region 22a) and ideally as close as possible to this edge 23a, and a downstream cut 29b located on the side of the edge 23b (or region 22b) and ideally as close as possible to this edge 23b. The cuts 29a and 29b are made in a manner known per se, for example by laser cutting. The cuts 29a and 29b are made through the entire thickness of the second texture 20 so as to allow the unfolding of the skins 26 separated from the rest of the second texture 20. The cuts 29a and 29b are made transversely, for example perpendicularly, to the direction DA. The cuts 29a and 29b can extend substantially to the bottom 27, and extend only over a part of the tangential dimension LA20 of the second texture 20.

[0039] Figure 4 illustrates the deployment of the cut assembly portions 26 relative to the rest of the second texture 20 according to the deployment arrows fl so as to position the portions 26 along the direction DR. Figure 5 shows Notch 40 is defined in region 24 on the side of edge BT1 when portions 26 are deployed. Notch 40 is axially delimited by axial edges resulting from cutouts 29a and 29b. Notch 40 opens onto edge BT1 and extends tangentially between edge BT1 and the bottom 27. Notch 40 is intended to accommodate the first texture 10, as will now be described in connection with Figures 6 and 7.

[0040] Figure 6 illustrates a first assembly 100 that can be implemented within the scope of the invention. The BT1 edge of a second texture 20 has been positioned on the intrados side of the first texture 10, and the BT1 edge of another second texture 20 has been positioned on the extrados side of the first texture 10. The portions 26 of each second texture 20 have been unfurled in opposite directions to bear against the first texture 10 and to fit the first texture 10 into the notches 40 of the second textures 20. In the illustrated example, an additional cut along the DA direction has been made to shorten the portions 26 before assembly, but omitting this cut does not depart from the scope of the invention. In the illustrated example, the second textures 20 are in partial overlap on regions 22a and 22b (overlap zone ZR), in particular on the entire axial dimension of these regions 22a and 22b.This overlap zone ZR can extend over a tangential dimension between 15% and 80% of the tangential dimension defined by the two assembled textures 20. However, the invention remains within the scope of the invention if there is no such overlap, as the textures 20 can alternatively be in edge-to-edge contact on the upstream and downstream end regions. Part 28 is intended to define a radially internal platform reinforcement, i.e., located on the side of the second region 50 and intended to delimit the vein on the inner side. The gap between the first texture 10 and the second textures 20 can be substantially zero, as the notches 40 can substantially follow the shape of the aerodynamic profile defined by the first region 30. In particular, the first texture 10 can be positioned substantially in contact with the bottom 27 during assembly.

[0041] In the example illustrated in [Fig. 6], the second textures 20 define, on region 22a, a portion 22a-2 which has been folded against the first texture 10 so as to define a preform of an upstream wall. This portion 22a-2 is extended by portion 22a-1, which is intended to define an upstream spoiler reinforcement. The downstream spoiler reinforcement is, in turn, intended to be defined by region 22b in the illustrated example. The spoilers serve to limit leakage of the primary vein flow by creating a baffle with the distributors.

[0042] The assembly variant 100-1 of [Fig. 7] is similar to the example in [Fig. 6] except for the structure of the second textures 20-1 and more particularly the downstream end region which includes a first part 22b-2 forming a preform of downstream wall folded down onto the first texture and which presents a detached part 22b-1 deployed in relation to part 22b-2 and which is intended to define a downstream spoiler reinforcement.

[0043] We have just described, in connection with Figures 6 and 7, cases where the assembly includes a preform of wall(s), but we do not depart from the scope of the invention when this is not the case. Furthermore, in the examples just described, the second textures 20 and 20-1 have two separate skins intended to form the assembly portions. The invention is not, however, limited to this arrangement, as illustrated in [Fig. 8], where each second texture 20-2 comprises a single cut assembly portion 26-2 that is deployed relative to the portion 28-2 intended to form the platform reinforcement. Those skilled in the art will recognize that other variations are possible, such as a second texture itself formed by two unit textures 20-2 superimposed at their portion 28-2.

[0044] Once the assembly is obtained, a common ceramic matrix is ​​produced allowing the first texture 10 and the second textures 20, 20-1 or 20-2 to be joined together and a continuous mechanical anchoring between them.

[0045] The formation of the common ceramic matrix is ​​achieved by implementing techniques known per se. For example, at least part of the matrix can be produced by chemical vapor infiltration. This allows a silicon carbide matrix phase to be obtained. As an example, chemical vapor infiltration can be limited to the formation of a consolidation phase that incompletely densifies the blade preform but is sufficient to allow it to maintain its shape without the assistance of a holding tool, and the formation of the ceramic matrix can be completed by another technique. In this respect, the matrix formation can be continued by reactive or non-reactive melt infiltration. A SiC matrix, or even a Si-SiC matrix, can be formed by infiltrating a molten silicon composition or a molten silicon alloy.

[0046] Once obtained, protective coatings, for example environmental barriers, can be applied to the blade in a manner known per se. The turbine blade's root can be mounted on a turbine wheel, and the blade is intended to be driven into rotation during operation.

[0047] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

Claims

Demands

1. A method for manufacturing a turbine blade made of ceramic matrix composite material, comprising: - the provision of a first fibrous texture (10) comprising a first region (30) for defining a reinforcement of a blade and a second region (50) for defining a reinforcement of a blade root to be obtained, - the provision of a pair of second fibrous textures (20; 20-1; 20-2) each having, successively along an axial direction (DA), an upstream end region (22a), a blade region (24), and a downstream end region (22b), each second texture having, in the blade region, at least one cut-out assembly portion (26; 26-2), formed by an upstream cut (29a) and a downstream cut (29b), each transverse to the axial direction, and located on the side of a tangential edge (BT1) of the assembly, said at least one portion assembly being suitable for deployment relative to the rest of the second texture so as to define,in the blade region on the side of the assembly edge, a notch (40) during its deployment, - the assembly of the second fibrous textures with the first fibrous texture by positioning the tangential assembly edge of each second texture on a respective intrados or extrados side of the first texture, by positioning each deployed assembly portion against the first texture and by positioning the first texture in the notches of the second textures, the parts (28) of the blade regions opposite the tangential assembly edge being intended to define a blade platform reinforcement to be obtained, and the second textures being intended to define, on the upstream and downstream end regions, at least one blade spoiler reinforcement to be obtained, and - a bonding of the first texture with the second textures, after assembly, by co-densification by a common ceramic matrix.

2. A method according to claim 1, wherein at least one of the second fibrous textures (20; 20-1) is formed by three-dimensional weaving and comprises two cut assembly portions (26) formed by unwoven, unbound fibrous skins between they on a zone (25) of unbinding, the assembly portions being deployed in opposite directions to be positioned against the first texture (10) during assembly.

3. A method according to claim 2, wherein each second texture (20; 20-1) is formed by three-dimensional weaving and comprises two cut assembly portions (26) formed by unbound fibrous skins not woven together on an unbound zone (25), the assembly portions of each second texture being deployed in opposite directions to be positioned against the first texture (10) during assembly.

4. A method according to any one of claims 1 to 3, wherein the second textures (20; 20-1) assembled to the first texture (10) define, on at least one of the upstream and downstream end regions (22a; 22b), a foldable part (22a-2; 22b-2) intended to form the reinforcement of a wall, and wherein the method further comprises, after assembly and before joining, folding the foldable part onto the first texture so as to define a preform of the wall.

5. A method according to claim 4, wherein the second textures (20; 20-1) assembled to the first texture (10) define, on each of the upstream and downstream end regions (22a; 22b), a foldable part (22a-2; 22b-2) intended to form the reinforcement of a wall, and wherein the method further comprises, after assembly and before joining, folding each foldable part onto the first texture so as to define an upstream wall preform and a downstream wall preform.

6. A method according to any one of claims 1 to 5, wherein the second textures (20; 20-1) are in partial overlap (ZR) on the upstream and downstream end regions (22a; 22b).

7. A method according to any one of claims 1 to 6, wherein the first texture (10) is formed by three-dimensional weaving.

8. A method according to any one of claims 1 to 7, wherein all or part of the common ceramic matrix is ​​formed by chemical vapor infiltration, infiltration of molten silicon or a molten silicon alloy being optionally carried out after chemical vapor infiltration to finalize the common ceramic matrix.

9. A fibrous assembly intended to form a reinforcement for a turbine blade made of a ceramic matrix composite material, comprising: - a first fibrous texture (10) comprising a first region (30) intended to define a reinforcement for a blade and a second region (50) intended to define a reinforcement for a blade root, and - a pair of second fibrous textures (20; 20-1; 20-2) assembled with the first fibrous texture, the second textures each having, in succession along an axial direction (DA), an upstream end region (22a), a blade region (24) and a downstream end region (22b), each second texture having, in the blade region, at least one assembly portion (26;26-2) cut out, formed by an upstream cutout (29a) and a downstream cutout (29b) each transverse to the axial direction, and located on the side of a tangential edge (BT1) of assembly, said at least one portion of assembly being deployed relative to the rest of the second texture so as to define, in the blade region on the side of the assembly edge, a notch (40), the tangential edge of assembly of each second texture being positioned on a respective intrados or extrados side of the first texture, each deployed portion of assembly being positioned against the first texture and the first texture being positioned in the notches of the second textures, the portions (28) of the blade regions opposite the tangential edge of assembly being intended to define a blade platform reinforcement, and the second textures being intended to define, on the upstream and downstream end regions, at least one blade spoiler reinforcement.;

10. Assembly according to claim 9, wherein at least one of the second fibrous textures (20; 20-1) is formed by three-dimensional weaving and comprises two cut assembly portions (26) formed by unbound fibrous skins not woven together on an unbound zone (25), the assembly portions being deployed in opposite directions and being positioned against the first texture (10).

11. Assembly according to claim 9 or 10, wherein the second textures (20; 20-1) assembled to the first texture (10) define, on at least one of the upstream and downstream end regions (22a; 22b), a folded part (22a-2; 22b-2) on the first texture intended to define a preform of wall.

12. Assembly according to any one of claims 9 to 11, wherein the second textures (20; 20-1) are in partial overlap (ZR) on the upstream and downstream end regions (22a; 22b).

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