Fibrous preform of a turbomachine blade

Abstract

Fibrous Preform of a Turbomachine Blade The present invention relates to a fibrous preform (10p) of a turbomachine blade, comprising: - a first part defining a reinforcement of an aerodynamic profile, and - a second part defining a platform reinforcement (15) and a blade reinforcement that extends continuously along a tangential direction (T), the blade reinforcement comprising, on a first side, a textile element (1631) from which extend a first (1632a) and a second (1632b) textile units unbound from each other along a tangential unbound, the first textile unit extending on the first side so as to define a part of the reinforcement of a first blade, and the second textile unit being cut from the platform reinforcement and separated from the first unit so as to extend on a second side and thus define all or part of the reinforcement of a second blade. Fig. 3.

Description

Title of the invention: Fibrous preform of a 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, and associated preforms, having tangential continuity between the blades. Description of the invention

[0005] The present description relates to a fibrous preform of a turbomachine blade, comprising: - a first part defining a reinforcement of an aerodynamic profile, and - a second part, located at a vertex of the first part, defining a platform reinforcement and a slat reinforcement that extends continuously along a tangential direction and transversely to the platform reinforcement, the slat reinforcement comprising, on a first intrados or extrados side, a textile element obtained by three-dimensional weaving from which extend a first and a second textile units unbound from each other along a tangential unbound direction, the first textile unit extending on the first side so as to define a part of the reinforcement of a first slat, and the second textile unit being cut from the platform reinforcement and separated from the first unit so as to extend on a second extrados or intrados side, opposite the first side, and thus to define all or part of the reinforcement of a second lick.

[0006] The invention aims to provide new turbomachine blades having tangential continuity between the blades so as to limit hot gas leaks through the inter-blade gap(s).

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

[0008] In one embodiment, the reinforcement of the slats further comprises, on the second side, a second textile element obtained by three-dimensional weaving from which extend a third and a fourth textile units unbound from each other along a second tangential unbound, the third textile unit extending on the second side and defining a part of the reinforcement of the second slat and being covered by the second unit, and the fourth textile unit being cut from the platform reinforcement and separated from the third unit so as to extend on the first side, to cover the first textile element and the first unit and thus to define a part of the reinforcement of the first slat.

[0009] Alternatively, the first textile unit and the textile element together form the reinforcement of the first lick, and the second textile unit forms the reinforcement of the second lick.

[0010] In one embodiment, the preform is woven in a single piece of three-dimensional fabric, the first part having, at its top, a radial unbundling, and the second part being formed by fibrous textures each originating from the first part and unbundled from the radial unbundling, each fibrous texture being folded down on a respective intrados or extrados side and transversely to the latter, the fibrous textures defining the platform reinforcement and at least one of them defining the swag reinforcement which is unbundled from a part of the platform reinforcement and deployed transversely to the latter, each textile element being cut on a tangential edge located on the side of the first part.

[0011] In particular, the preform can be obtained by three-dimensional weaving of first yarns with second yarns, the first yarns being able to extend in a radial direction, and the fibrous texture located on the first side being able to comprise a number of layers of first yarns greater than the number of layers of first yarns in the other fibrous texture.

[0012] The present disclosure also relates to a turbomachine blade made of ceramic matrix composite material, comprising a fibrous reinforcement formed by a preform as described above, and a ceramic matrix densifying said reinforcement.

[0013] In one embodiment, the blade is a turbine blade.

[0014] 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

[0015] The attached drawings are schematic and are intended primarily to illustrate the principles of the exposition. [Fig. 1] Fig. 1 is a schematic cross-sectional view of a turbofan engine. [Fig. 2] Fig. 2 schematically represents a fibrous blank being shaped to form a first example of a fibrous preform according to the invention. [Fig.3] Fig.3 schematically represents the first example of a fibrous preform observed in top view along the radial direction. [Fig.4] Fig.4 represents, schematically, the first example of fibrous preform observed along the axial direction. [Fig.5] Fig.5 represents, schematically and partially, a fibrous blank being shaped to form a second example of a fibrous preform according to the invention, seen from above in the radial direction. [Fig.6] Fig.6 represents, schematically and partially, the second example of fibrous preform observed in top view along the radial direction. [Fig.7] Fig.7 represents, schematically, an example of a turbine blade according to the invention. Description of the implementation methods

[0016] 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.

[0017] 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).

[0018] The primary stream 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.

[0019] The secondary flow, on the other hand, bypasses the hot part of the reactor.

[0020] The compressors 3, 4 and the turbines 5, 6 comprise several stages of fixed blades (called "stators") and moving blades (called "rotors").

[0021] 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 to hold the blade in place during the operation of the turbomachine.

[0022] 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.

[0023] 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.

[0024] In the present exposition, the term "lower" is defined with respect to the main direction of the blades; the terms "axial", "radial", "tangential", "inner", "outer" 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.

[0025] We will now describe various examples of fibrous preforms for turbomachine blades according to the invention. The examples described, in connection with Figures 2 to 6, concern the case where the preform was obtained by weaving a three-dimensional fabric in a single piece. By "three-dimensional fabric" or "3D fabric," we mean 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 the roles between warp and weft is possible and should be considered as also covered by the claims. The production of the fibrous preform by 3D weaving makes it possible to obtain a bond between the layers, thus ensuring good mechanical strength of both the fibrous preform and the resulting composite material part, in a single textile operation. The fibrous preform may, for example, have an interlock weave.The term "interlock weave or fabric" refers to a three-dimensional weave in which each layer of weft yarns interlocks 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 weaves is, of course, not outside the scope of the invention. Various suitable weaving techniques are described in document WO 2006 / 136755.

[0026] The 3D weaving technique is a known technique per se, as is the formation of unbindings which is exploited within the scope of the present invention. In a manner known per se, an unbinding is made between two layers of warp yarns by not making The invention avoids passing weft threads through the unlinking zone to prevent binding warp layer threads located on either side of the unlinking. As will be detailed below, the invention also proposes to perform local cuts, which are implemented using techniques known per se.

[0027] 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.

[0028] Generally, the fibrous preform can be made of ceramic wires, for example, silicon carbide wires. The fibrous preform can constitute the fibrous reinforcement of the composite part to be obtained. Examples of usable silicon carbide wires include "Nicalon," "Hi-Nicalon," "Hi-Nicalon-S," or Tyranno SA3 wires from UBE Industries. The ceramic wires of the fibrous preform can have an oxygen content of 1% or less. "Hi-Nicalon-S" wires, for example, have this characteristic.

[0029] Figure 2 shows an example of a fiber blank 10e being shaped, which defines a reinforcement 12 of an airfoil that has, at a vertex SO, a radial joint denoted DR. The joint DR defines two fiber textures 14a, 14b that are separated from each other and deployed transversely with respect to the reinforcement 12. Each texture 14a, 14b is folded back on one respective side (intrados or extrados) of the reinforcement 12 and transversely to the latter. Each texture 14a, 14b extends either on the intrados or extrados side. The textures 14a, 14b define a reinforcement 15 of a platform. In the example considered here, each texture 14a, 14b is derived from the reinforcement 12, that is to say that the reinforcement 12 extends, beyond the unbonding DR, to form the two unbound fibrous textures 14a, 14b.Thus all the warp thread layers of textures 14a, 14b (taken here as the threads extending along the R direction before folding of textures 14a, 14b) are found in the reinforcement 12. If we denote N, NI and N2 respectively the number of warp thread layers in the reinforcement 12, the number of warp thread layers in texture 14a intrados and the number of warp thread layers in texture 14b extrados, we can thus have the following relationship: N = NI + N2. .

[0030] In the illustrated example, textures 14a and 14b are not of the same thickness; texture 14a alone carries the textile portions 163 intended to form the reinforcement of the flaps. Thus, the textile portions 163 are located here on the same intrados or extrados side. More precisely, texture 14a comprises, in the illustrated example, a woven zone 161 with reinforcement 15 and located radially outside the latter, the portions 163 each extending from an axial edge BA161 distinct from zone 161 and being unbound from reinforcement 15. Each portion 163 has been cut in the vicinity of the unbound DR (cut edge BT 163) so as to be able to be deployed transversely to the reinforcement 15 (arrow fl) and obtain the configuration illustrated in [Fig.2],

[0031] Each portion 163 has a tangential debonding DT that defines a first textile unit 1632a and a second textile unit 1632b, debonded from each other so that they can be separated. Units 1632a and 1632b extend from a textile element 1631 obtained by three-dimensional weaving, which is located on the side of the debonding DR (or on the side of the reinforcement 12). Units 1632a and 1632b may also have a three-dimensional weave. Element 1631 was cut along the edge BT163.

[0032] The fibrous preform 1Op is obtained by unfolding the second unit 1632b, which is cut on its radially lower part at line 166 to separate it from the reinforcement 15 and then moved away from the first unit 1632a (unfolding arrow f2) so as to be folded over on the opposite side as illustrated in Figures 3 and 4. In the example illustrated in Figures 3 and 4, the first unit 1632a and element 1631 together form the reinforcement of one strip, and the second unit 1632b forms the reinforcement of another strip located on the opposite side. The reinforcement of the first and second strips extends continuously along the tangential direction T due to the textile continuity between units 1632a and 1632b ensured by element 1631.

[0033] Figures 5 and 6 represent an alternative embodiment based on a similar principle to the example just described, but in which the blank 100e further comprises additional textile portions 164 located on the opposite side to the portions 163 and having a similar structure, each with a tangential unbundling DT that defines a third textile unit 1642a and a fourth textile unit 1642b unbundled from each other so as to be able to be separated. The units 1642a and 1642b extend from a second textile element 1641 obtained by three-dimensional weaving, which is located on the side of the unbundling DR (or on the side of the reinforcement 12 described previously). The units 1642a and 1642b may also have a three-dimensional weave. Element 1641 was clipped on the BT 164 edge. In this example, the 14 unbound textures folded on each side of the DR unbound can have substantially the same thickness.

[0034] The fibrous preform 1OOp is obtained by unfolding the second unit 1632b as described above along the unfolding arrow f21, but also by unfolding the fourth unit 1642b symmetrically to the second unit 1632b along the unfolding arrow f22. The second unit 1632b thus unfolded covers the second textile element 1641 and the third unit 1642a, and the fourth unit 1642b thus deployed covers the first textile element 1631 and the first unit 1632a. The first element 1631, the first unit 1632a and the fourth unit 1642b together form the reinforcement of a slit and the second element 1641, the third unit 1642a and the second unit 1632b together form the reinforcement of another slit located on the opposite side.

[0035] We have just described various examples of fibrous blade preforms according to the invention. The blade is then obtained by forming a ceramic matrix in a porosity of the preform.

[0036] The formation of this matrix relies on 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 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, 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.

[0037] Once obtained, protective coatings, for example environmental barrier coatings, can be applied conventionally to the blade.

[0038] 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 runner blade, such as that illustrated in [Fig.7],

[0039] The blade 100 of [Fig.7] comprises, a blade 101 whose reinforcement is formed by the reinforcement 12 which has been described above, a foot 102 formed by a thicker part, for example with a bulb-shaped cross-section, extended by a strut 103, an inner platform 110 located between the strut 103 and the blade 101 and an outer platform 120 equipped with scrapers, in the vicinity of the free end of the blade, formed as described above.

[0040] The blades 100 can then be mounted on a turbine disc by positioning the foot 102 of the blades 100 in a corresponding housing of the disc.

[0041] 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.

[0042] 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 restrictive sense.

Claims

Demands

1. A fibrous preform (1Op; 1OOp) of a turbomachine blade (100), comprising: - a first part defining a reinforcement (12) of an aerodynamic profile, and - a second part, located at a vertex (SO) of the first part, defining a platform reinforcement (15) and a slat reinforcement which extends continuously along a tangential direction (T) and transversely to the platform reinforcement, the slat reinforcement comprising, on a first intrados or extrados side, a textile element (1631) obtained by three-dimensional weaving from which extend a first (1632a) and a second (1632b) textile units unbound from each other along a tangential unbound direction (DT), the first textile unit extending on the first side so as to define a part of the reinforcement of a first slat,and the second textile unit being cut from the platform reinforcement and separated from the first unit so as to extend over a second extrados or intrados side, opposite to the first side, and thus defining all or part of the reinforcement of a second stripe.

2. Preform (100p) according to claim 1, wherein the slat reinforcement further comprises, on the second side, a second textile element (1641) obtained by three-dimensional weaving from which extend a third (1642a) and a fourth (1642b) textile units unbound from each other along a second tangential unbound (DT), the third textile unit extending on the second side and defining a part of the reinforcement of the second slat and being covered by the second unit (1632b), and the fourth textile unit being cut from the platform reinforcement and separated from the third unit so as to extend on the first side, to cover the first textile element (1631) and the first unit (1632a) and thus to define a part of the reinforcement of the first slat.

3. Preform (1Op) according to claim 1, wherein the first textile unit (1632a) and the textile element (1631) together form the reinforcement of the first lick, and the second textile unit (1632b) forms the reinforcement of the second lick.

4. Preform (1Op; 1OOp) according to any one of claims 1 to 3, wherein the preform is woven in a single piece of three-dimensional fabric, the first part having, at its apex (SO), a radial unbinding (DR), and the second part being formed by fibrous textures (14; 14a; 14b) each originating from the first part and unbound from the radial unbinding, each fibrous texture being folded down on a respective intrados or extrados side and transversely to the latter, the fibrous textures defining the platform reinforcement (15) and at least one of them defining the swag reinforcement which is unbound from a part of the platform reinforcement and deployed transversely to the latter, each textile element (1631; 1641) being cut on a tangential edge (BT 163; BT 164) located on the side of the first part.

5. Preform (lOp) according to claim 4 related to claim 3, wherein the preform is obtained by three-dimensional weaving of first yarns with second yarns, the first yarns extending in a radial direction (DR), and the fibrous texture located on the first side comprising a number of layers of first yarns greater than the number of layers of first yarns in the other fibrous texture.

6. Turbomachine blade (100) of ceramic matrix composite material, comprising a fibrous reinforcement formed by a preform (lOp; lOOp) according to any one of claims 1 to 5, and a ceramic matrix densifying said reinforcement.

7. Blade (100) according to claim 6, wherein the blade is a turbine blade.

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