Method for manufacturing a hollow stator blade with an internal reinforcement

Abstract

The invention relates to a method for producing a hollow stator blade with an internal reinforcement, said method comprising:-producing a fibrous blank (100) having a structure of aerodynamic profile by means of three-dimensional weaving of yarns, the present invention relates to a method for manufacturing a preform (100), the preform comprising two skins (110, 111), an inner shell (104a) located between the skins, one or more first fibrous reinforcements (140) extending in the inner shell, and one or more second fibrous reinforcements (150, 160) extending in the inner shell, the first and second fibrous reinforcements defining a chamber (112, 113, 114, 115, 116, 117) therebetween in the inner shell (104a); -inserting a soluble core (171, 172, 173, 174, 175, 176) into the chamber of the inner housing; injecting a resin into the fibrous preform and converting the resin into a matrix, thereby obtaining an intermediate piece of a stator blade made of composite material, comprising an inner volume between the two skins, the inner volume containing reinforcements, each reinforcement being in contact with the inner surface of the skin, at least some of the reinforcements comprise one or more flow channels; and dissolving the core present in the chamber.

Description

TECHNICAL FIELD

[0001] The present invention relates to the general field of blades for gas turbine aeroengines and to a method for manufacturing the same. BACKGROUND

[0002] The present invention more particularly relates to stator blades or stationary blades, such as outlet guide vanes or “OGVs”, or variable pitch stator blades or “VSVs” (“variable stator vanes”).

[0003] In order to obtain lighter blades, it is known to manufacture composite blades, i.e. blades manufactured by manufacturing a structural part having a fibrous reinforcement densified by a matrix.

[0004] Document US2005 / 0084377 describes a method for manufacturing a whole composite turbine blade, the blade being manufactured by three-dimensional weaving of a fibrous preform and densification of the preform by a matrix. Although this method allows obtaining a blade having high mechanical strength, the overall mass of the blade remains important, in particular for large size blades.

[0005] In order to reduce the overall mass of composite blades, methods have been developed allowing manufacturing hollow blades. In certain of them, one or more foam parts are used to form the woven fibrous blank. For example, document US20220097824 discloses a method for manufacturing a composite blade using a shaped foam to form a fibrous structure obtained by three-dimensional weaving.

[0006] However, foams represent a non-negligible cost and require particular precautions due to their sensitivity to humidity.

[0007] Therefore, in order to maintain a good mechanical strength of the internal volume of the blade, one solution is to provide the blade with an internal reinforcement. Document WO2022263743 discloses a method for manufacturing a fibrous blade preform, the internal volume of which is provided with an internal reinforcement.

[0008] However, forming a fibrous preform provided with an internal reinforcement can prove complex, in particular when it is wished to obtain a blade having an empty internal volume. Indeed, in this case, the shaped part or core used to form the blade preform must be extracted at the end of the manufacturing. Therefore, the internal volume must have a geometry allowing the removal of the shaped part, which greatly limits the possibility of integrating an internal reinforcement in the blade. In document WO2022263743, the internal reinforcement extends in the radial direction of the blade along the internal surface of the skin of the blade, which allows dismounting the shaped part used. SUMMARY

[0009] It would therefore be desirable to propose a solution for manufacturing a stator blade of composite material, which offers greater freedom in terms of the design and positioning of the stiffeners in the internal volume of the blade.

[0010] To this end, the application proposes a method for manufacturing a turbine stator blade, comprising:

[0011] - manufacturing a fibrous blank of a structure having an aerodynamic profile by three-dimensional weaving of yarns, said blank comprising a first skin and a second skin, an internal shell present between the skins, one or more first fibrous stiffeners extending in a first direction in the internal shell and one or more second fibrous stiffeners extending in a second direction in the internal shell, the first and second directions intersecting, in the internal shell, said first and second fibrous stiffeners defining a chamber between them,

[0012] - inserting a soluble core into the chamber of the internal shell, to obtain a fibrous preform,

[0013] - maintaining the fibrous preform in an injection tooling mold cavity having the shape of the stator blade to be manufactured,

[0014] - injecting resin into the mold cavity containing the fibrous preform and transforming the resin into a matrix by heat treatment, thereby obtaining an intermediate piece of a stator blade of composite material comprising an internal volume between two skins, the internal volume comprising one or more first stiffeners extending in a first direction and one or more second stiffeners extending in a second direction, each stiffener being in contact with an internal surface of said skins, at least part of the stiffeners comprising one or more flow channels,

[0015] - dissolving the core present in the chamber.

[0016] With the method of the application, it is possible to form a hollow blade comprising internal stiffeners extending in different directions, and the internal volume between the stiffeners is empty. Indeed, certain chambers are inaccessible at the end of the manufacturing, which hinders the manual disassembly or dissolution of the core present in these chambers. By using soluble cores and creating flow channels in the stiffeners, it is possible to dissolve all the cores used to form the blade.

[0017] The blade thus obtained comprises one or more internal stiffeners which, in addition to increasing the stiffness of the blade skins at their internal volume, advantageously form parts that can break in the event of impact of the aerodynamic structure of the blade with an ingested object or a fragment that damages the blade. In this case, the stiffeners absorb most of the impact energy, thus enabling the blade to retain its integrity. The overall mass of the blade is also optimized, since the internal volume of the blade is empty, apart from the stiffeners.

[0018] According to a particular feature of the method of the application, the first fibrous reinforcements extend in the internal shell in a radial direction and the second fibrous reinforcements extend in the internal shell in an axial direction.

[0019] According to another particular feature of the method of the application, at least part of the first and second fibrous reinforcements are formed by three-dimensional weaving on the internal surface of the first skin or of the second skin.

[0020] According to another particular feature of the method of the application, at least part of the first and second fibrous reinforcements comprise one or more layers of unidirectional yarns held on the internal surface of the first skin or of the second skin.

[0021] According to another particular feature of the method of the application, during the insertion of the soluble core into the cavity of the internal shell, the soluble cores are connected together by soluble connecting rods positioned on at least part of the fibrous reinforcements of the fibrous blank, the connecting rods forming flow channels in at least part of the reinforcements of the stator blade.

[0022] According to another particular feature of the method of the application, the soluble cores can be salt cores (for example zirconium salt cores), or sand cores, or cores mixed with salt and sand.

[0023] The application also relates to a composite stator blade comprising a fibrous reinforcement densified by a matrix, the stator blade comprising a structure having an aerodynamic profile comprising a first skin and a second skin and an internal volume located between the skins, the stator blade further comprising: one or more first reinforcements extending in the internal volume in a first direction and one or more second reinforcements extending in the internal volume in a second direction, the first direction and the second direction intersecting, the first reinforcements and the second reinforcements being integral with the internal surfaces of the first skin and of the second skin, at least part of the reinforcements comprising one or more channels.

[0024] According to the blade of the application, the blade in particular comprises one or more reinforcements which, in addition to increasing the stiffness of the skin of the blade at its internal volume, advantageously form parts which can break in the event of impact of the aerodynamic structure of the blade with an ingested object or a fragment damaging the blade. In this case, the reinforcements absorb a significant part of the impact energy, thus enabling the blade to retain its integrity. The overall mass of the blade is also optimized, since the internal volume of the blade is empty, apart from the reinforcements.

[0025] According to a particular feature of the stator blade of the application, the first reinforcements extend in the internal volume in a radial direction and the second reinforcements extend in the internal volume in an axial direction.

[0026] According to another specific feature of the stator blade of the application, at least a portion of said first and second reinforcements has a three-dimensional weave structure connected to the inner surface of the first skin or of the second skin.

[0027] According to another specific feature of the stator blade of the application, at least a portion of said first and second reinforcements comprises one or more layers of unidirectional yarns held on the inner surface of the first skin or of the second skin. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a perspective view of a stator blade according to an embodiment of the application.

[0029] Figure 2 is a schematic view illustrating the three-dimensional weaving of a fibrous blank used to manufacture a structure having the aerodynamic profile of the blade of Figure 1 .

[0030] Figure 3A is a larger scale partial cross-sectional view of a set of yarn layers forming the blank of Figure 1 .

[0031] Figure 3B is another larger scale partial cross-sectional view of a set of yarn layers forming the blank of Figure 1 .

[0032] Figure 4 is an exploded view showing the manufacturing of the preform of the blade of Figure 1 .

[0033] Figure 5 is a perspective view showing the preform of the blade obtained.

[0034] Figure 6 is a cross-sectional view of the preform of Figure 5 .

[0035] Figure 7 is a schematic exploded perspective view showing the injection tooling and the preform of Figure 6 placed therein.

[0036] Figure 8 is a schematic perspective view showing the injection tooling of Figure 7 in a closed state during the step of injecting resin.

[0037] Figure 9 is a perspective view of an intermediate piece obtained after injection and polymerization of resin in the preform of Figure 5 .

[0038] Figure 10 is a cross-sectional view of the intermediate piece of Figure 9 . DETAILED DESCRIPTION

[0039] The present invention is generally applicable to different types of stator blades or stationary blades used in aircraft engines. Some non-limiting examples are in particular outlet guide vanes, referred to as OGVs. The present invention is particularly applicable, but not limited to, stator blades having a large size for which reducing the overall mass of the blade is of particular interest.

[0040] In the following part of the description, one example of implementation of the method of the invention is described in connection with the manufacture of a flow straightener blade or OGV for an unducted fan, referred to as "open rotor", in an aircraft engine.

[0041] Figure 1 A composite stator blade 10 for mounting on an unducted fan of an aircraft turboprop engine is shown, comprising in a known manner: a structure 20 having an aerodynamic profile for forming the aerodynamic part of the blade. The stator blade generally comprises a root for connecting said stator blade to the fan, which root is not shown in Figure 1 the figures for the sake of simplifying the illustration. The structure 20 having an aerodynamic profile has a curved profile in its cross section, the thickness of which is variable between a leading edge 20a and a trailing edge 20b.

[0042] The aerodynamic structure 20 comprises: a pressure side skin 21 and a suction side skin 22 and an internal volume 30 present between the skins 21 and 22.

[0043] In the example described here and in accordance with the invention, in the internal volume 30 there is present: a first reinforcement, here a vertical reinforcement 40, extending in a first direction, here a radial direction D R , and two second reinforcements, here two horizontal reinforcements 50 and 60, extending in a second direction, here an axial direction D A . The vertical reinforcement 40 extends between an inlet 30c and a bottom 30d of the internal volume 30. The horizontal reinforcements 50 and 60 extend between an upstream edge 30a and a downstream edge 30b of the internal volume 30. The first reinforcement, here the reinforcement 40, can extend in the internal volume 30 between the inlet 30c and the bottom 30d in a first direction different from the radial direction D R , and the second reinforcements, here the two reinforcements 50 and 60, can extend in the internal volume 30 between the upstream edge 30a and the downstream edge 30b in a second direction different from the axial direction D AA second direction extends between the upstream edge 30a and the downstream edge 30b of the internal volume 30, said first direction and said second direction intersecting. The vertical stiffeners 40 as well as the horizontal stiffeners 50 and 60 are in contact with and integrally formed with the inner surface 21a of the pressure side skin 21 and the inner surface 22a of the suction side skin 22 of the blade. In the example described herein, the aerodynamic structure 20 as well as the stiffeners 40, 50 and 60 comprise a fiber reinforcement with a three-dimensional weaving densified by a matrix, as explained in more detail below. The internal volume 30 is empty at all of its parts, except for the locations where the stiffeners are present.

[0044] In the example described herein, the blade 10 is provided with a single first stiffener in its internal volume, here a vertical stiffener. However, a stator blade according to the present application can comprise a higher number of first stiffeners. In particular, the number of first stiffeners is determined according to the stiffness requirements of the skin at the internal volume of the blade with respect to the vibrational loads applied on the blade during operation and / or the need to ingest objects.

[0045] Also, the blade 10 described herein is provided with two second stiffeners, here two horizontal stiffeners. However, a stator blade according to the present application can comprise only a single second stiffener or more than two stiffeners. In addition to reinforcing the mechanical strength (stiffness) of the blade at its internal volume, the second stiffeners advantageously form a portion that can break in case of impact of the aerodynamic structure of the blade with an ingested object or a fragment that damages the blade. In this case, the second stiffeners absorb a large part of the impact energy, thus enabling the blade to maintain its integrity.

[0046] Also in the example described herein, the first stiffener, here the vertical stiffener 40, comprises channels or grooves 41, 42 and 43 facing the inner surface 21a of the pressure side skin 21. Also, the second stiffeners, here the horizontal stiffeners 50 and 60, comprise channels or grooves 51, 52 and 61, 62, respectively, facing the inner surface 21a of the pressure side skin. These channels are formed in order to facilitate the dissolution of the forming cores used in the manufacturing process, as will be described below. These channels can also advantageously form a frangible area, facilitating the breaking of the stiffeners in case of impact with an object.

[0047] Figure 2 A fiber blank 100 is very schematically shown, which is used to form a fiber preform having the aerodynamic profile of the blade.

[0048] As Figure 2 Schematically shown, the fiber blank 100 is obtained by three-dimensional (3D) weaving, which is done in a known manner on a jacquard loom, on which the warp yarns 101 or yarn bundles are arranged in multiple layers of about one hundred yarns per layer, which are connected by weft yarns 102.

[0049] In the example shown, 3D weaving is a weaving with an "interlocking" pattern. "Interlocking" weaving, as used here, refers to a weaving pattern in which each layer of weft yarns is interconnected with multiple layers of warp yarns, and all yarns in the same weft column move in the same direction within the pattern plane.

[0050] Other known types of 3D weaving can be used, especially those described in document WO 2006 / 136755.

[0051] The fiber preform can be woven using carbon fiber or ceramic fiber (such as silicon carbide) yarn.

[0052] During the weaving of the fiber preform, its thickness and width are variable, and a certain number of warp yarns are not woven, which allows for a continuously variable desired profile and thickness of the preform 100. An example of adaptive 3D weaving is described in reference EP 1 526 285, which in particular allows the preform thickness to vary between a first edge used to form the leading edge and a second edge of smaller thickness used to form the trailing edge; the contents of that reference are incorporated herein by reference.

[0053] During weaving, between two continuous warp layers inside the fiber preform and in the separation region 104 ( Figure 4 Separation section 103 is generated on the surface. Figure 2 The separation region 104 allows for the provision of an internal shell 104a within the fiber preform 100 for forming a preform with an aerodynamic profile.

[0054] Using the 3D weaving pattern of the interlocking pattern of blank 100 through Figure 3A and Figure 3B It is shown schematically. Figure 3A This is a partial enlarged view of two planes (continuous warp cross-sections) in the portion of the blank 100 without the separating section (i.e., the blank area outside the separating section 103), and... Figure 3B The blank 100 shows two planes (continuous warp cross sections) in a portion of the separation section 103 that forms the separation region 104.

[0055] In this example, the blank 100 comprises six layers of warp yarns 101 extending along the X direction. Figure 3A In the middle, six layers of warp yarns are interconnected through weft yarns T1 to T5. Figure 3BIn this structure, the three warp layers 101 forming part or skin 110 are interconnected by two weft yarns T1 and T2, and similarly, the three warp layers forming part or skin 111 are interconnected by two weft yarns T4 and T5. In other words, the fact that weft yarns T1 and T2 do not extend into part 111 and weft yarns T4 and T5 do not extend into part 110 provides a separating portion 103 that separates part 110 and part 111 from each other.

[0056] At the end of the knitting ( Figure 2 For example, using pressurized water jets, the warp and weft yarns are cut at the extreme boundaries of the knit to extract, such as... Figure 4 The blank 100 shown is produced after 3D weaving and before any forming. A separation region 104 provided during weaving allows the formation of two sections 110 and 111, which are woven independently of each other, defining an inner shell 104a within the blank 100. These two sections 110 and 111 form the portions of the pressure-side skin 21 and suction-side skin 22 of the aerodynamic structure 20 within the hollow internal volume 30. The inner shell 104a opens at its lower edge 100c. The leading edge 100a of the fiber blank 100 connects the two sections 110 and 111 and forms the leading edge 20a of the aerodynamically contoured structure 20 of the blade 10, while the trailing edge 100b of the blank 100 corresponds to the section used to form the aerodynamically contoured structure (…). Figure 1 The trailing edge 20b of the part.

[0057] like Figure 4 As shown, the fiber preform 100 includes within the inner housing 104a: a first fiber reinforcement (here, a vertical fiber reinforcement 140), which extends along a first direction (here, the radial direction D). R , corresponding to the extension direction of the warp yarn 101 in the blank 100; and two second reinforcements (here, two horizontal fiber reinforcements 150 and 160) extending along a second direction (here, the axial direction D). A (corresponding to the extension direction of the weft yarn 102 in the blank 100). The first fiber reinforcement (here, fiber reinforcement 140) can extend in a direction different from the radial direction D. R The first fiber reinforcement extends in the direction of the axial direction, while the second fiber reinforcement (here, two fiber reinforcements 150 and 160) can extend in a direction different from the axial direction D. A The second direction extends, and the first direction and the second direction intersect.

[0058] Fiber reinforcements 140, 150, and 160 are here formed by three-dimensional weaving simultaneously with the three-dimensional weaving of the fiber preform 100. Fiber reinforcements 140, 150, and 160 are integrally woven with the inner surface of portion 111 of the preform 100, but are not connected by weaving to the inner surface of portion 110 of the preform 100. This allows for the provision of channels for inserting a shaped core between portions 110 and 111 and between fiber reinforcements 140, 150, and 160, as explained below. Fiber reinforcements 140, 150, and 160 define chambers 112, 113, 114, 115, 116, and 117 between them and within the inner housing 104a, as... Figure 4 As shown.

[0059] As mentioned earlier, the number of the first or second fiber reinforcement can vary between one or more reinforcements, depending on the required stiffness and impact resistance of the blade.

[0060] According to a variant embodiment, all or part of the first and second fiber reinforcements may be formed from one or more unidirectional yarn layers retained on the inner surface of one of portions 110 and 111 of the preform. Reinforcements formed from unidirectional yarn layers are described in document WO2022263743.

[0061] According to the present invention and as follows Figure 4 As shown, the fiber preform 100 is formed by introducing soluble cores into the inner housing 104a. More precisely, soluble cores 171, 172, 173, 174, 175, and 176 are introduced and arranged in chambers 112, 113, 114, 115, 116, and 117 present in the inner housing 104a of the fiber preform 100, respectively. In the example described here, the soluble cores 171, 172, 173, 174, 175, and 176 are interconnected by horizontal connecting rods 177 and vertical connecting rods 178. This allows the formation of an array 170 with cores 171, 172, 173, 174, 175, and 176, thereby facilitating the insertion of all cores into the inner housing.

[0062] Once the array 170 of cores 171, 172, 173, 174, 175, and 176 is introduced and positioned within the inner shell 104a of the fiber preform 100, a fiber blade preform 200 is obtained, as shown below. Figure 5 As shown, the preform includes a preform portion 211 with an aerodynamic profile, which is composed of a dry fiber preform 100, in which cores 171, 172, 173, 174, 175 and 176 are positioned in a cavity defined by fiber reinforcements 140, 150 and 160 within an inner shell 104a.

[0063] Horizontal connecting rod 177 overlaps with vertical fiber reinforcement 140, while vertical connecting rod 178 overlaps with horizontal fiber reinforcements 150 and 160. Here, the connecting rods also function to form flow channels within the reinforcements to facilitate the removal of the soluble core at the end of manufacturing, as explained below. In fact, as... Figure 6 As shown in the horizontal fiber reinforcement 160, each connecting rod 178 forms a channel or groove in the reinforcement 160, which may become more apparent after the preform is compacted.

[0064] According to one variant embodiment, soluble cores 171, 172, 173, 174, 175, and 176 can be used independently (without array 170) to be positioned individually in their respective chambers. In this case, independent elements of the same or different material as the cores can be placed on the fiber reinforcements where flow channels are desired to form. According to one variant, the reinforcements include different compacted regions that allow for the formation of flow channels.

[0065] Preform portion 211 with aerodynamic profile along the lateral direction D T It extends between the leading edge portion 211a and the trailing edge portion 211b.

[0066] The fiber preform is then densified. Densification of the fiber preform used to form the fiber reinforcement of the part to be manufactured involves filling the pores (all or part of the volume) of the preform with the material constituting the matrix. This densification is accomplished using liquid phase infiltration (LPI) in a manner known per se. Liquid phase infiltration involves impregnating the preform with a liquid composition containing a matrix material precursor. The precursor is typically in the form of a polymer (e.g., a high-performance epoxy resin) and may be soluble in a solvent. The preform is placed in a mold that can be sealed closed, the cavity of which has the shape of the final molded blade. The mold is then closed, and the liquid matrix precursor (e.g., a resin) is injected into the entire cavity to impregnate the entire fiber portion of the preform.

[0067] The conversion of the precursor to the matrix (i.e., its polymerization) is accomplished by heat treatment, typically by heating the mold after removing any possible solvents and crosslinking the polymer. The preform is always held in a mold with a shape corresponding to the shape of the part to be produced.

[0068] In the case of forming a carbon or ceramic matrix, the heat treatment includes pyrolyzing the precursor to convert it into a carbon or ceramic matrix, depending on the precursor used and the pyrolysis conditions. For example, liquid ceramic precursors (especially SiC precursors) can be resins of the polycarbosilane (PCS), polytitanium carbosilane (PTCS), or polysilazane (PSZ) type, while liquid carbon precursors can be resins with a relatively high residual carbon content, such as phenolic resins. Several consecutive cycles (from impregnation to heat treatment) can be performed to achieve the desired degree of densification.

[0069] According to one aspect of the invention, particularly in the case of forming an organic matrix, densification of the fiber preform can be accomplished by a known transfer molding method known as RTM (“Resin Transfer Molding”). According to the RTM method, the fiber preform is placed in a mold having the external shape of the part to be produced. A thermosetting resin is injected into the internal space of the mold containing the fiber preform. Typically, a pressure gradient is established between the resin injection point and its discharge port within this internal space to control and optimize the impregnation of the preform with the resin.

[0070] like Figure 7 As shown, the injection of the matrix precursor liquid composition into the fiber structure and its conversion into a matrix are performed here in an injection fixture 300, which includes: a first housing 310 having a first cavity 311 at its center, the first cavity portion corresponding to the shape and size of the blade to be manufactured; and a second housing 320 having a second cavity 321 at its center, the second cavity portion corresponding to the shape and size of the blade to be manufactured.

[0071] Once tooling 300 is shut down, such as Figure 9 As shown, the first cavity 311 and the second cavity 321 together define an internal volume 301 having the shape of the blade to be manufactured, in which the fiber preform 200 is placed. Compaction of the fiber preform 200 can be performed when the tooling 300 is closed to obtain a predetermined yarn content in the preform. In this case, compaction pressure is applied to the housings 310 and 320 by, for example, a press. Compaction of the fiber preform can also be performed in a separate tooling before the preform is introduced into the injection tooling.

[0072] The tooling 300 also includes means for allowing injection of the matrix precursor liquid and for converting the precursor into a matrix. More precisely, in the example described here, the first housing 310 of the tooling 300 includes an injection port 313 for allowing injection of the matrix precursor liquid composition into the fiber preform, while the second housing includes a discharge port 323 for cooperating with a vacuum system to evacuate and expel air from within the tooling during injection. The injection tooling 300 also includes a lower portion 340 and an upper portion 350, with the first housing 310 and the second housing 320 positioned between the lower portion 340 and the upper portion 350, both equipped with heating devices (not included). Figure 8 (As shown in the image).

[0073] Once tooling 300 is closed, the blade is molded by impregnating the preform 200 with a thermosetting resin polymerized through heat treatment. For this purpose, a known injection molding or transfer method, known as RTM ("Resin Transfer Molding"), is used. According to the RTM method, resin 380 (e.g., a thermosetting resin) is injected through injection port 313 of the first housing 310 into the internal volume occupied by the preform 200. Port 323 of the second housing 320 is connected to a discharge pipe maintained under pressure (not in...). Figure 8 (As shown in the diagram). This configuration allows a pressure gradient to be established between the lower part of the preform 200 (the resin injection point) and the upper part of the preform located near port 323. In this way, the resin 380 injected essentially at the lower part of the preform will gradually impregnate the entire preform by flowing through it until it reaches the discharge port 323, through which excess resin is discharged. Of course, the first housing 310 and the second housing 320 of the tooling 300 may each include multiple injection ports and multiple discharge ports. The RTM method can also be performed under vacuum (VA-RTM).

[0074] The resin used can be, for example, an epoxy resin with a temperature rating of 180°C. Resins suitable for the RTM method are well known. They preferably have low viscosity to facilitate injection into the fibers. The selection of the resin's chemical properties and / or temperature rating is determined based on the thermomechanical loads the component must withstand. Once the resin is injected into the entire reinforcement, its polymerization begins according to the RTM method via heat treatment.

[0075] The densification method described above allows for the production of stator blades primarily from organic matrix (CMO), carbon matrix (C / C), and ceramic matrix (CMC) composite materials from the fiber preforms of the present invention.

[0076] After injection, polymerization, and demolding, the following is obtained: Figure 9 The intermediate part 400 of the composite material shown has a fiber reinforcement consisting of a fiber preform 200 and a matrix densified.

[0077] The intermediate component 400 includes an aerodynamic profile portion 411 for forming the aerodynamic structure 20 of the stator blade 10 to be manufactured. The aerodynamic profile portion 411 includes two skins 421 and 422 for forming the pressure-side skin 21 and suction-side skin 22 of the blade 10, respectively.

[0078] The aerodynamic profile portion 411 includes an internal volume 430, which exists between skins 421 and 422 and serves to form the internal volume 30 of the blade 10. The internal volume 430 contains a vertical stiffener 440 and two horizontal stiffeners 450 and 460, all of which are composite materials, for forming the vertical stiffener 40 and the horizontal stiffeners 50 and 60 of the stator blade 10, respectively. The stiffeners 440, 450, and 460 are connected to the skin 422 by weaving, as previously described (fiber stiffeners 140, 150, and 160 are integrally woven with portion 111 of the preform 100). At this stage of manufacturing, the stiffeners 440, 450, and 460 are also connected to the skin 421 by a co-densification process, which is completed between the stiffeners 440, 450, and 460 and the skin 421 during resin injection and polymerization in the fiber preform 200. The aerodynamic profile portion 411 includes: soluble cores 171, 172, 173, 174, 175, and 176, which are located within a cavity defined between stiffeners 440, 450, and 460; and connecting rods 177 and 178, which are located at the stiffeners. Figure 10 As shown, for the horizontal reinforcement 460, each connecting rod 178 forms a channel or groove in the reinforcement 460, which is larger than the preform due to the compaction of the preform. Figure 6 It is even more obvious in the middle.

[0079] Cores 171, 172, 173, 174, 175, and 176, as well as connecting rods 177 and 178, are made of a soluble material to allow for removal from the intermediate component 400. In fact, the presence of the two horizontal reinforcing members here hinders the removal of cores 172, 173, 175, and 176 from component 400. The cores and connecting rods are made of a soluble material or a mixture thereof. They may be made of salt (e.g., zirconium salt) or sand. Cores may also be made of a mixture of salt and sand.

[0080] The process then begins by dissolving and removing the cores 171, 172, 173, 174, 175, and 176 present in the intermediate 400. To this end, in the example described herein, a first hole 180 is first made in core 171, and a second hole 181 is made in core 174. A dissolving fluid F1 is then introduced into the first hole 180 to gradually dilute the cores and connecting rods, allowing a flow loop of the dissolving fluid to be formed in all chambers containing the cores. A fluid F2 containing the dissolving fluid F1 and loaded with dissolved material from the cores is discharged. Holes 180 or 181 serve as trigger points for the initial dissolution of cores 171 and 174, followed by the dissolution of the non-demoldable cores 172, 173, 175, and 176. Specifically, the dissolving fluid can be water, a heated alkaline solution, or any fluid capable of dissolving the core material.

[0081] Once the core is completely dissolved and discharged from the internal volume of the intermediate part 400, it can be trimmed as necessary to remove excess resin and chamfered. No further machining is required because the part is molded to the required dimensions. This yields... Figure 1 10 stator blades.

Claims

1. A method for manufacturing a turbomachinery stator blade (10), the method comprising: A fiber preform (100) with an aerodynamic profile is manufactured by three-dimensional weaving of yarns. The preform includes a first skin (110) and a second skin (111), an inner shell (104a) located between the skins, one or more first fiber reinforcements (140) extending in the inner shell along a first direction, and one or more second fiber reinforcements (150, 160) extending in the inner shell along a second direction, the first and second directions intersecting each other. In the inner shell (104a), the first fiber reinforcements and the second fiber reinforcements define a cavity (112, 113, 114, 115, 116, 117) between them. Soluble cores (171, 172, 173, 174, 175, 176) are inserted into the chambers of the inner shell to obtain a fiber preform (200). The fiber preform (200) is held in the mold cavity (301) of an injection fixture (300) having the shape of the stator blade to be manufactured. Resin (380) is injected into the mold cavity (301) containing the fiber preform (200), and the resin is converted into a matrix by heat treatment to obtain an intermediate part (400) of the composite stator blade, the intermediate part comprising an internal volume (430) located between two skins (421, 422), the internal volume comprising one or more first reinforcements (440) extending in a first direction and one or more second reinforcements (450, 460) extending in a second direction, each reinforcement contacting the inner surface of the two skins, at least a portion of the reinforcement comprising one or more flow channels. Dissolve the core present in the chamber.

2. The method according to claim 1, wherein, The first fiber reinforcement (140) is located in the inner housing along the radial direction (D) R ) extends, and wherein the second fiber reinforcement (150, 160) extends in the inner housing along the axial direction (D A )extend.

3. The method according to claim 1 or 2, wherein, At least a portion of the first fiber reinforcement (140) and the second fiber reinforcement (150, 160) is formed by three-dimensional weaving on the inner surface of the first skin (110) or the second skin (111).

4. The method according to any one of claims 1 to 3, wherein, At least a portion of the first fiber reinforcement (140) and the second fiber reinforcement (150, 160) includes one or more unidirectional yarn layers held on the inner surface of the first skin (110) or the second skin (111).

5. The method according to any one of claims 1 to 4, wherein, During the insertion of the soluble core into the chamber of the inner housing, the soluble cores (171, 172, 173, 174, 175, 176) are connected together by soluble connecting rods (177, 178) positioned on at least a portion of the fiber reinforcement of the fiber preform, the connecting rods forming flow channels in at least a portion of the stator blade reinforcement.

6. The method according to any one of claims 1 to 5, wherein, The soluble cores (171, 172, 173, 174, 175, 176) are zirconium salt cores or sand cores, or cores of a mixture of zirconium salt and sand.

7. A stator blade (10) of a composite material, comprising: The stator blade comprises a fiber-reinforced matrix and includes a structure (20) having an aerodynamic profile, the structure including a first skin (21) and a second skin (22) and an internal volume (30) between the skins. The stator blade also includes one or more first reinforcing members (40) extending in the internal volume (30) along a first direction and one or more second reinforcing members (50, 60) extending in the internal volume along a second direction, the first direction and the second direction intersecting each other. The first reinforcing members and the second reinforcing members are integrally formed with the inner surfaces (21a, 22a) of the first skin (21) and the second skin (22). At least a portion of the reinforcing members includes one or more channels (41, 42, 43, 51, 52, 61, 62).

8. The blade according to claim 7, wherein, The first reinforcing member (40) is located in the radial direction (D) of the internal volume (30). R ) extends, and wherein the second reinforcement extends axially in the internal volume (D A )extend.

9. The blade according to claim 7 or 8, wherein, At least a portion of the first reinforcing member (40) and the second reinforcing member (50, 60) has a three-dimensional woven structure connected to the inner surfaces (21a, 22a) of the first skin (21) and the second skin (22).

10. The blade according to any one of claims 7 to 9, wherein, At least a portion of the first reinforcing member (40) and the second reinforcing member (50, 60) includes one or more unidirectional yarn layers held on the inner surfaces (21a, 22a) of the first skin (21) and the second skin (22).

Images