CMC turbomachine blade

Abstract

CMC Turbomachine Blade The present invention relates to a turbomachine blade (110) made of ceramic matrix composite material, comprising: - a first part of an aerodynamic profile and a second part, located at a vertex of the first part, defining a platform (15d) and blades (163ad; 163bd; 163cd;163dd) which extend transversely to the platform, a fibrous reinforcement of the second part comprising a first portion defining a reinforcement of a first strip (163ad) located on the intrados side and a second portion defining a reinforcement of a second strip (163bd) located on the extrados side, the first and second portions being spaced along a tangential direction so as to define a gap between them, and a tangential continuity element (180ad) of ceramic material, reinforced or not, positioned on the second part and integral with the latter, the tangential continuity element being opposite or inside the gap and configured to oppose a flow of gas through the gap along an axial direction. Fig. 6.;

Description

Title of the invention: CMC turbomachine blade technical field

[0001] The present disclosure relates to the design of turbomachine blades made of ceramic matrix composite (CMC) material, in particular turbine blades. Prior art

[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. In particular, US2017 / 198591 discloses the production of continuous tangential blades from a weaving of a woven blank.

[0004] The invention aims to provide new turbomachine blades having tangential continuity between the blades. Description of the invention

[0005] The present description relates to a turbomachine blade made of ceramic matrix composite material, comprising: - a first part of the aerodynamic profile and a second part, located at a vertex of the first part, defining a platform and winglets extending transversely to the platform, a fibrous reinforcement of the second part comprising a first portion defining a reinforcement of a first winglet located on the lower surface and a second portion defining a reinforcement of a second winglet located on the upper surface, the first and second portions being spaced along a tangential direction so as to define a gap between them, and - a tangential continuity element made of ceramic material, reinforced or not, positioned on the second part and attached to it, the tangential continuity element being opposite or inside the gap and configured to oppose a flow of gas through the gap along an axial direction.

[0006] The invention aims to provide new turbomachine blades having tangential continuity between the blade tips so as to limit hot gas leakage through the inter-blade gap(s). Furthermore, the presence of the tangential continuity element stiffens the blade tip. This results in improved mechanical strength of the tip under centrifugal force.

[0007] The invention is expressed in different embodiments which are detailed below.

[0008] In one embodiment, the tangential continuity element comprises an excess fraction of the ceramic matrix densifying the reinforcement of the second part which extends outside of this reinforcement to fill the gap.

[0009] Alternatively, the tangential continuity element comprises a central portion disposed in the gap, and at least one pair of connecting portions extending from the central portion and each attached to a respective slit.

[0010] In particular, the connecting portions can be offset along an axial direction.

[0011] In particular, the tangential continuity element may, in addition, comprise a pair of additional connecting portions extending from the central portion and each attached to a respective slit.

[0012] In particular, the bonding portions, and any additional bonding portions, can be bonded to the licks by the ceramic matrix densifying the latter.

[0013] In particular, the tangential continuity element can be composite and can include a reinforcement structure in the shape of the central portion and connecting portions as well as possible additional connecting portions, the reinforcement structure being able to be joined to the strips by forming a common ceramic matrix.

[0014] In one embodiment, the reinforcement of the second part further comprises a third portion defining a reinforcement of a third strip located on the intrados side and offset from the first portion along an axial direction, and a fourth portion defining a reinforcement of a fourth strip located on the extrados side and offset from the second portion along the axial direction, the third and fourth portions being spaced along the tangential direction so as to define a second gap between them, offset from the first gap along the axial direction.

[0015] In particular, the blade may further include an additional tangential continuity element, reinforced or not, positioned on the second part opposite or inside the second gap and configured to oppose a flow of gas through the second gap along the axial direction.

[0016] In particular, the tangential continuity element can be located between the first and second gaps and can include a base portion positioned on the platform and walls extending transversely to the base portion and each positioned opposite a respective gap.

[0017] In particular, the tangential continuity element can be composite and can include a reinforcement structure in the shape of the base portion and the walls, the reinforcement structure being able to be joined to the slats and the platform by forming a common ceramic matrix.

[0018] In one embodiment, the blade is a turbine blade.

[0019] In one embodiment, the fibrous reinforcement of the second part and a reinforcement The fibrous parts of the first section are obtained by three-dimensional weaving.

[0020] The aforementioned features and advantages, as well as others, will become apparent from the following detailed description which refers to the attached drawings. Brief description of the drawings

[0021] The attached drawings are schematic and are intended primarily to illustrate the principles of the exposition.

[0022] [Fig.1] Fig.1 is a schematic cross-sectional view of a turbofan engine.

[0023] [Fig.2] Fig.2 represents an example of fibrous reinforcement of a blade of turbomachine according to the invention.

[0024] [Fig.3] Fig.3 represents, schematically and partially, a first example of a turbomachine blade according to the invention observed along the axial direction.

[0025] [Fig.4] Fig.4 represents, schematically and partially, the first example of turbomachine blade according to the invention in top view along the radial direction.

[0026] [Fig. 5] [Fig. 5] represents, schematically and partially, a top view along the radial direction, a reinforcement of a second example of a turbomachine blade according to the invention, including a reinforcement structure of a tangential continuity element.

[0027] [Fig.6] [Fig.6] The [Fig.6] represents, schematically and partially, a top view along the radial direction, the second example of a turbomachine blade according to the invention after densification of the reinforcement of the [Fig.5].

[0028] [Fig.7] [Fig.7] The [Fig.7] represents, schematically and partially, a top view along the radial direction, a third example of a turbomachine blade according to the invention.

[0029] [Fig.8] [Fig.8] The [Fig.8] represents, schematically and partially, a top view along the radial direction, a fourth example of a turbomachine blade according to the invention.

[0030] [Fig.9] The [Fig.9] represents a cross-sectional view along IX-IX of the dawn of the [Fig.8]. Description of the implementation methods

[0031] Fig. 1 represents, in section along a vertical plane passing through its main axis A, a turbofan engine 1. It comprises, from upstream to downstream along the airflow circulation, 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.

[0032] 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).

[0033] 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 a high pressure turbine 6 and then a low pressure turbine 7 before undergoing acceleration through a nozzle.

[0034] The secondary flow, on the other hand, bypasses the hot part of the reactor.

[0035] The compressors 3, 4 and the turbines 5, 6 comprise several stages of fixed blades (called "stators") and moving blades (called "rotors").

[0036] 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.

[0037] 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.

[0038] The hot sections of the turbojet engine, located downstream of chamber 5, can incorporate CMC components such as CMC turbine blades. The following section describes various examples of CMC blade architectures according to the invention.

[0039] In the present exposition, the terms "axial", "radial", "tangential", and their derivatives are defined with respect to the main axis of the turbomachine; and the terms "upstream" and "downstream" are defined with respect to the flow of gas in the turbomachine.

[0040] The examples that will be described illustrate the case of a fibrous reinforcement of the first and second parts of the blade, which is obtained by weaving a three-dimensional fabric in a single piece. By "three-dimensional fabric" or "3D fabric," we mean here a weaving method in which at least some of the weft yarns bind warp yarns over several warp layers. It should be noted that there is a reversal of roles between warp and The weft is possible and should be considered as covered by the claims. The production of the fibrous preform by 3D weaving allows for bonding between the layers, thus ensuring good mechanical strength of both the fibrous preform and the resulting composite part, all in a single textile operation. The fibrous preform can, for example, have an interlock weave. "Interlock weave or fabric" refers to a three-dimensional weave in which each layer of weft yarns connects several layers of warp yarns, with all yarns in the same weft column having the same movement within the plane of the weave. The use of other types of 3D weaving is, of course, not outside the scope of the invention. Various suitable weaving techniques are described in document WO 2006 / 136755.

[0041] The 3D weaving technique is a known technique per se, as is the formation of unlinks, which is exploited in the examples that will be described. In a manner known per se, an unlink is created between two layers of warp yarns by not passing weft yarns through the unlink zone so as not to bind yarns from warp layers located on either side of the unlink. The examples also propose localized cutting, which is implemented using techniques known per se.

[0042] However, those skilled in the art will recognize that the present invention is not limited to the case of a blade reinforcement made from a single piece of fabric. In fact, alternatively, the reinforcement for the first part and the reinforcement for the second part can be manufactured separately and the latter attached to the top of the first part. It should also be noted that the present invention is not limited to the production of a reinforcement by 3D weaving.

[0043] Generally, the fibrous reinforcement of the blade can be made of ceramic fibers, for example, silicon carbide fibers. Examples of suitable silicon carbide fibers include "Nicalon," "Hi-Nicalon," "Hi-Nicalon-S," or Tyranno SA3 fibers from UBE Industries. The ceramic fibers of the fibrous reinforcement can have an oxygen content of 1% or less. "Hi-Nicalon-S" fibers, for example, have this characteristic.

[0044] Figure 2 shows an example of a fibrous reinforcement 10, shaped to the desired blade, which defines a reinforcement 12 of an airfoil that has, at a vertex SO, a radial joint denoted DR. The joint DR defines two fibrous textures 14 that are separated from each other and deployed transversely with respect to the reinforcement 12. Each texture 14 is folded back on one respective side (intrados or extrados) of the reinforcement 12 and transversely to the latter. Each texture 14 extends either on the intrados side or the extrados side. The textures 14 define a reinforcement 15 of a platform and several textile portions 163a, 163b, 163c, 163d forming the reinforcement of the slats which extend transversely to the reinforcement 15. More precisely, each texture 14 comprises, in the illustrated example, a woven area 161 with the reinforcement 15 and located radially outside with respect to the latter, the portions 163a and 163c, or 163b and 163d, each extending from an axial edge BA161 distinct from the area 161 and being unbound from the reinforcement 15. Each portion 163a-da has been cut in the vicinity of the unbound DR (cut edge 164) so ​​as to be able to be deployed to form a slat reinforcement.

[0045] The textures 14 comprise a first portion 163a that defines a reinforcement of a first flap located on the lower surface and a second portion 163b that defines a reinforcement of a second flap located on the upper surface. In the illustrated example, the first 163a and second 163b portions may be located substantially in the same position along an axial direction A. The first 163a and second 163b portions are spaced along a tangential direction T (non-zero distance e) so as to define a first gap 165a between them. The first gap 165a may have an elongated shape along the radial direction R, for example, be in the form of a slot. The width e of the first gap 165a, measured along the tangential direction T, may be substantially constant along the radial direction R, as illustrated. This width e is, for example, between 0.1 mm and 10 mm.The first 163a and second 163b portions can be separated from each other by the first gap 165a along their entire height, taken along the radial direction R (they are not in contact along their entire height).

[0046] In the illustrated example, the textures 14 further include a third portion 163c which defines a reinforcement of a third flap located on the lower surface and offset from the first portion 163a along the axial direction, and a fourth portion 163d which defines a reinforcement of a fourth flap located on the upper surface and offset from the second portion 163b along the axial direction. In the illustrated example, the third 163c and fourth 163d portions can be located substantially in the same position along an axial direction A. The third 163c and fourth 163d portions are spaced along a tangential direction T so as to define a second gap 165b between them. As with the first gap 165a, the second gap 165b may have an elongated shape along the radial direction R, for example be in the form of a slit.The width e of the first gap 165b, measured along the tangential direction T, can be substantially constant along the radial direction R, as illustrated. This width e is, for example, between 0.1 mm and 10 mm. The width of the first gap 165a can be substantially equal to that of the second gap 165b, or different. The third 163c and fourth 163d portions can be separated from each other by the second gap 165b. gaps 165b along their entire height, taken along the radial direction R (they are not in contact along their entire height). The gaps 165a and 165b can, as illustrated, be located in the extension of each other along the axial direction A. A case with two gaps is described here, but this does not, of course, depart from the scope of the invention if only two licks are defined with a single gap, or if more than two inter-lick gaps are present.

[0047] Figures 3 and 4 represent a first example of blade 100 according to the invention obtained after densification of the reinforcement 10 of [Fig.2].

[0048] The blade 100 comprises a first aerodynamic profile portion 12d and a second portion, located at a vertex of the first portion 12d, defining a platform 15d and slats 163ad, 163bd, 163cd, and 163dd that extend transversely to the platform 15d. The gaps 165a and 165b were filled during densification by an excess fraction of the ceramic matrix of the reinforcement 10 located outside the reinforcement 10 to form the tangential continuity elements 170a and 170b. For example, the elements 170a and 170b can be obtained by overfilling the reinforcement 10 (extending beyond the reinforcement 10) with an infiltration composition comprising silicon or a molten silicon alloy. Elements 170a and 170b can, as illustrated, substantially fill the entire gaps 165a and 165b (over their entire height and width).Elements 170a and 170b can, as illustrated, extend from an intrados slit to an extrados slit located opposite the intrados slit along the T direction.

[0049] Generally speaking, matrix formation relies on techniques known per se. For example, at least part of the matrix can be produced by chemical vapor infiltration (CVI). This allows a silicon carbide matrix phase to be obtained. As an example, CVI can be limited to the formation of a consolidation phase that incompletely densifies the preform but is sufficient to allow it to maintain its shape without the assistance of holding tools, and the formation of the ceramic matrix can be completed by another technique. In this respect, 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.

[0050] Figure 5 shows a reinforcement of a second example of a turbomachine blade according to the invention. This reinforcement comprises the previously described reinforcement 10 onto which reinforcement structures 180a, 180b have been attached, each defining a central portion 182a, 182b disposed in the gap 165a, 165b, and a pair of connecting portions 184a, 184b extending from the central portion 182a, 182b and positioned on a separate portion 163a or 163b, or 163c or 163d depending on the reinforcement structure. Each central portion 182a, 182b can occupy substantially the entirety of the corresponding gap 165a, 165b (extending across its entire height and width). For each structure 180a, 180b, a first connecting portion can overlap part of an upstream face of a first portion 163a, 163c, and a second connecting portion, distinct from the first portion, can overlap part of a downstream face of a second portion 163b, 163d. Thus, the first and second connecting portions can be offset along direction A. This overlap can occur on a minority of the faces of portions 163a-163d, its sole function being to secure the continuity element to the slats.

[0051] After densification, with here the formation of a common ceramic matrix between the reinforcement 10 and the structures 180a and 180b, we obtain the blade 110 illustrated in [Fig.6] which comprises two tangential continuity elements 180ad, 180bd each comprising a central portion 182ad, 182bd disposed in the gap 165a, 165b (and occupying substantially the entirety of the corresponding gap 165a, 165b), and a pair of connecting portions 184ad, 184bd extending from the central portion 182ad, 182bd and integral with a distinct lip 163ad or 163bd, or 163cd or 163dd depending on the tangential continuity element considered.

[0052] The example just described, in connection with Figures 5 and 6, concerns a tangential continuity element having a substantially S-shaped form when viewed from above along the direction R. The third example of a blade 120 according to the invention, illustrated in [Fig. 7], shows a different, H-shaped geometry for the tangential continuity elements. This third example differs from the previously described case only in that the two tangential continuity elements 190ad, 190bd each comprise two pairs of connecting portions 194ad and 196ad or 194bd and 196bd, each extending from the central portion 192ad or 192bd. The characteristics described above remain applicable to this example.

[0053] A person skilled in the art will recognize that the tangential continuity elements just described in relation to figures 3 to 7 can apply to the case where only an inter-lick gap is present.

[0054] The fourth example of a blade 130 according to the invention, illustrated in Figures 8 and 9, comprises a single tangential continuity element 200d whose reinforcement structure defines a base portion 202d positioned on the platform and two walls 204d extending transversely to the portion 202d and each positioned opposite a respective gap 165a, 165b to close it. As above, the element 200d can be secured to the blades 163a-d by forming a common matrix. In the example considered, the element 200d extends over the entire tangential dimension of the platform, but those skilled in the art will recognize that this does not depart from the scope of the invention when this is not the case.

[0055] In connection with Figures 5 to 9, the case of reinforced tangential continuity elements bonded to the molding edges by a common matrix has been described. The use of a reinforcing structure for these elements is not essential, and alternatively, monolithic ceramic elements can be inserted during molding and bonded to the reinforcement by adding matrix during densification.

[0056] The invention is applicable to different types of turbomachine blades, in particular compressor and turbine blades of different gas turbine bodies, for example a low pressure turbine wheel blade.

[0057] The blades can then be mounted on a turbine disc by positioning the base of the blades in a corresponding housing of the disc.

[0058] The components according to the invention can be fixed to different types of turbine rotors, in particular compressor and turbine rotors of various gas turbine bodies, for example a low-pressure (LP) turbine rotor disc. Components according to the invention can be fixed to low- or high-pressure turbojet turbines.

[0059] Although the present invention has been described with reference to specific embodiments, those skilled in the art will recognize 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 a restrictive sense.

Claims

Demands

1. Turbomachine blade (100; 110; 120; 130) made of ceramic matrix composite material, comprising: - a first part (12d) of an aerodynamic profile and a second part, located at a vertex of the first part, defining a platform (15d) and slats (163ad; 163bd; 163cd; 163dd) which extend transversely to the platform, a fibrous reinforcement of the second part comprising a first portion (163a) defining a reinforcement of a first slat (163ad) located on the lower surface and a second portion (163b) defining a reinforcement of a second slat (163bd) located on the upper surface, the first and second portions being spaced along a tangential direction (T) so as to define a gap (165a) between them, and - an element (170a; 180ad; 190ad;200d) tangential continuity element in ceramic material, reinforced or not, positioned on the second part and integral with the latter, the tangential continuity element being opposite or inside the gap and configured to oppose a flow of gas through the gap along an axial direction (A).;

2. Blade (100) according to claim 1, wherein the tangential continuity element (170a) comprises an excess fraction of the ceramic matrix densifying the reinforcement of the second part which extends outside of this reinforcement to fill the gap (165a).

3. Blade (110; 120) according to claim 1, wherein the tangential continuity element (180ad; 190ad) comprises a central portion (182ad; 192ad) disposed in the gap (165a), and at least one pair of connecting portions (184ad; 194ad; 196ad) extending from the central portion and each integral with a respective slat (163ad; 163bd).

4. Blade (110; 120) according to claim 3, wherein the connecting portions (184ad; 194ad; 196ad) are offset along an axial direction (A).

5. Blade (120) according to claim 3 or 4, wherein the tangential continuity element (190ad) further comprises a pair of additional connecting portions (196ad) extending from the central portion (192ad) and each integral with a respective slat (163ad; 163bd).

6. Blade (110; 120) according to any one of claims 3 to 5, wherein the connecting portions (184ad; 194ad), and any additional connecting portions (196ad), are bonded to the blades (163ad; 163bd) by the ceramic matrix densifying the latter.

7. Blade (110; 120) according to claim 6, wherein the tangential continuity element (180ad; 190ad) is composite and comprises a reinforcement structure in the shape of the central portion (182ad; 192ad) and connecting portions (184ad; 194ad) as well as optional additional connecting portions (196ad), the reinforcement structure being bonded to the blades (163ad; 163bd) by the formation of a common ceramic matrix.

8. Blade (100; 110; 120; 130) according to any one of claims 1 to 7, wherein the reinforcement of the second part further comprises a third portion (163c) defining a reinforcement of a third slat (163cd) located on the intrados side and offset from the first portion (163a) along an axial direction (A), and a fourth portion (163d) defining a reinforcement of a fourth slat (163dd) located on the extrados side and offset from the second portion (163b) along the axial direction, the third and fourth portions being spaced along the tangential direction (T) so as to define a second gap (165b) between them, offset from the first gap (165a) along the axial direction.

9. Blade (100; 110; 120) according to claim 8, wherein the blade further comprises an additional tangential continuity element (180bd; 190bd), reinforced or not, positioned on the second part opposite or inside the second gap (165b) and configured to oppose a flow of gas through the second gap along the axial direction (A).

10. Blade (130) according to claim 8 related to claim 1 or 2, wherein the tangential continuity element (200d) is located between the first (165a) and second (165b) gaps and comprises a base portion (202d) positioned on the platform (15d) and walls (204d) extending transversely to the base portion and each positioned opposite a respective gap.

11. Blade (130) according to claim 10, wherein the tangential continuity element (200d) is composite and comprises a structure of

12.

13. reinforcement to the shape of the base portion (202d) and the walls (204d), the reinforcement structure being joined to the ledges (163ad-163dd) and to the platform (15d) by the formation of a common ceramic matrix. Blade (100; 110; 120; 130) according to any one of claims 1 to 11, wherein the blade is a turbine blade. Blade (100; 110; 120; 130) according to any one of claims 1 to 12, wherein the fibrous reinforcement of the second part and a fibrous reinforcement of the first part are obtained by three-dimensional weaving.

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