TURBO MACHINE SHOVEL WITH METAL LEADING EDGE

Description

Technical Field

[0001] The present invention relates to the general field of blades for aeronautical gas turbine engines or aeronautical turbomachines made of composite material and more particularly to turbomachine blades with metallic leading edge. Previous technique

[0002] In order to protect the composite blade of a turbine blade from abrasion, erosion and / or impacts with a foreign body, the blades include a reinforced leading edge, and more specifically a one-piece titanium leading edge.

[0003] This titanium leading edge is bonded to the blade. However, this type of leading edge results in significant material and manufacturing costs, as well as non-conformities throughout its entire lifecycle.

[0004] Indeed, the cost of titanium is high, and manufacturing the blade involves numerous steps and generates material waste. Furthermore, when assembling the titanium leading edge onto the blade, the blade surface must be prepared before bonding the leading edge, which requires prior curing in a long autoclave cycle. The cavity in the blade that receives the leading edge must also be adapted; it is often too wide or too narrow, resulting in undulations and / or striations on the blade's vanes.

[0005] During the manufacture of intermediate parts for the production of a blade including such a leading edge, non-conformities can also be observed on the part entering assembly while the intermediate part (titanium leading edge) was compliant.

[0006] It is also difficult to repair such a damaged leading edge without changing the entire leading edge assembly.

[0007] Document WO 2019 / 186029 describes a turbomachine blade comprising a metallic shim on the leading edge of the blade with an adhesive between the shim and the blade.

[0008] Document FR 2 943 102 describes a blade formed of unidirectional folds and including a metallic shim on the leading edge.

[0009] It is therefore desirable to have an aeronautical turbomachine blade that is less expensive to manufacture and maintain and more easily repairable. Description of the invention

[0010] The invention relates to a turbomachine blade comprising a blade made of composite material with fiber reinforcement densified by a matrix, the fiber reinforcement being obtained from a three-dimensional weave of fibers, and a metallic leading edge formed by a metallic shim, the shim having an intrados fin and an extrados fin which extend respectively over intrados and extrados faces of the blade following an aerodynamic profile of the blade, characterized in that the blade also comprises at least one unidirectional fabric ply of composite material on the leading edge between the blade and the metallic shim, each fabric ply extending at least partially over the intrados and extrados faces of the blade.

[0011] Such a leading edge can be easily assembled onto the blade and repaired without touching or damaging the blade's composite structure, as it is sufficient to replace the damaged and / or non-conforming shim with another shim that will only be in contact with the unidirectional fabric plies. Furthermore, the leading edge of the invention allows for lower-cost design, production, and repair of the blade. Indeed, the metallic shim has a significantly thinner profile than a one-piece titanium leading edge, thus reducing material costs during blade manufacturing or repair.

[0012] It is also easier to adapt to particular blade geometry constraints with this type of leading edge, such as reinforcing one of the blade faces by extending the metallic shims on the intrados or extrados face of the blade without modifying the internal structure of the blade.

[0013] According to one embodiment of the invention, the metallic shim extends over a first length on the intrados face of the blade and over a second length on the extrados face of the blade.

[0014] This allows the design of a blade whose metallic reinforcement provided by the shim extends over a greater length on the intrados (or extrados) face compared to the extrados (or intrados) face of the blade.

[0015] According to another embodiment of the invention, the first and second lengths are equal.

[0016] This allows us to obtain a leading edge that is symmetrical with respect to an axis connecting the leading edge and the trailing edge of the blade.

[0017] According to a particular feature of the invention, each unidirectional fabric fold extends over an entire internal surface of the intrados and extrados fins of the tinsel.

[0018] This prevents direct contact between the metal shim and the blade. Replacing the metal shim will therefore be simplified, as it will not affect the internal structure of the blade and there will be no need to prepare the blade surface before installing the new shim.

[0019] According to one embodiment of the invention, the blade comprises a plurality of unidirectional fabric folds of composite material on the leading edge between the metal shim and the blade, the folds of the plurality of fabric folds being draped over one another and extending at least partially over the intrados and extrados faces of the blade.

[0020] The unidirectional fabric pleats protect the internal structure of the blade in case of leading edge damage and replacement of the metal shims. Furthermore, because the pleats are draped over one another, the waviness or rippling that can occur between the multiple layers of fabric during blade manufacturing, use, or repair is prevented.

[0021] According to a particular feature of the invention, a film of glue is present between said at least one-way fabric fold and the metallic foil.

[0022] According to another particular feature of the invention, once the draping of the unidirectional fabric folds has been carried out, the metallic shim and the rest of the blade are co-injected.

[0023] According to another particular feature of the invention, a film of glue is present between said at least one unidirectional fabric ply and the auger.

[0024] These different characteristics (glue film, co-injection and draping) make it possible to keep the metallic tinsel in place on the unidirectional fabric folds, and to keep the unidirectional folds in place on the blade.

[0025] According to another particular feature of the invention, the composite material of each unidirectional fabric ply comprises Kevlar fibers.

[0026] According to another particular feature of the invention, the blade is a three-dimensional piece woven with glass fibers, the weaving being able to be partial or total.

[0027] According to another particular feature of the invention, the metallic slender has a thickness of between 0.1 mm and 0.5 mm on the intrados and extrados faces.

[0028] According to another particular feature of the invention, said at least one unidirectional fabric ply has a thickness between 0.15 mm and 0.25 mm.

[0029] According to another particular feature of the invention, the set of unidirectional fabric folds has a thickness between 0.2 mm and 1 mm.

[0030] According to another particular feature of the invention, the blade constitutes an outlet guide blade, an inlet guide blade, a blower blade or a variable pitch blade.

[0031] Another object of the invention is a method for repairing a turbomachine blade according to the invention, comprising removing the metal shim, preparing a surface for a new metal shim and placing said new metal shim on at least one unidirectional fabric ply. Brief description of the drawings

[0032] Other features and advantages of the present invention will become apparent from the description given below, with reference to the attached drawings which illustrate examples of embodiment without any limiting character. [ Fig. 1 ] There figure 1 represents, schematically and partially, a view of a blade according to one embodiment of the invention. Fig. 2 ] There figure 2 represents, schematically and partially, a cross-sectional view of a blade according to one embodiment of the invention. Fig. 3 ] There figure 3 represents, schematically and partially, a cross-sectional view of a blade according to one embodiment of the invention. Fig. 4 ] There figure 4 represents a flowchart showing the different stages of a blade repair process according to an embodiment of the invention. Description of the implementation methods

[0033] The dawn depicted on the figures 1 à 3 For example, it could be a fixed blade or a flow straightener.

[0034] There figure 1 The diagram schematically and partially represents a blade 100 according to the invention. The blade 100 comprises a blade 140 which extends along a longitudinal direction L, corresponding to a radial direction when the blade 100 is mounted in a turbomachine, between an inner platform 141 and an outer platform 142. The blade 140 extends along a transverse direction T between a leading edge 150 and a trailing edge 151.

[0035] The 140 blade is made of three-dimensional composite material, specifically a fiber-reinforced composite material densified by a matrix. The fiber reinforcement may include carbon fibers, and the matrix may be organic and obtained from a densifying resin. Alternatively, the fiber reinforcement may include woven glass fibers.

[0036] The leading edge 150 of the blade 140 is covered by a metallic shim 120 placed on the blade 140 following an aerodynamic profile of the blade 140.

[0037] At least one unidirectional fabric ply made of composite material (not shown on the figure 1 ) is placed between the blade 140 and the shim 120 on the leading edge 150.

[0038] There figure 2 represents, schematically and partially, a cross-sectional view of blade 240 of a blade 200, according to plan II of the figure 1 , according to one embodiment of the invention.

[0039] The metallic shim 220 comprises an intrados fin 221 and an extrados fin 222 which extend respectively over a part of the intrados face 241 and a part of the extrados face 242 of the blade 240. The fins 221 and 222 are integrated into the blade 240 so that they follow the aerodynamic profile of the blade 200 by defining a part of this aerodynamic profile.

[0040] According to the invention, the blade 200 also comprises at least one unidirectional fabric ply of composite material 230 placed between the metal shim 220 and the blade 240. For example, the figure 2 Only one ply 230 is shown. This fabric ply 230 prevents direct contact between the shim 220 and the fibrous structure of the blade 240.

[0041] In the example of the figure 2 The shim 220 and the fabric fold 230 extend over the same length on the lower surface 241 and the upper surface 242 of the blade 240. The fabric fold 230 therefore extends over the entire inner surface of the lower surface 221 and upper surface 222 of the shim 220. The shim 220 is also symmetrical with respect to an axis extending between the leading edge 250 and the trailing edge of the blade 200.

[0042] The fabric pleat 230 has a thickness between 0.15 mm and 0.25 mm. The metallic foil 220 has a thickness between 0.1 mm and 0.5 mm.

[0043] There figure 3 represents, schematically and partially, a cross-sectional view of the blade 340 of a blade 300 according to another embodiment of the invention.

[0044] The metallic shim 320 always includes an intrados fin and an extrados fin which extend respectively over a part of the intrados face 341 and a part of the extrados face 342 of the blade 340. The fins are always integrated into the blade 340 so as to follow the aerodynamic profile of the blade 300.

[0045] In the example shown, the blade 300 comprises a plurality of unidirectional fabric folds 330. In particular, the example of the figure 3 comprises three plies 331, 332 and 333. The plies 331, 332 and 333 are draped over one another. The draping can, for example, be carried out from unidirectional unit plies pre-impregnated with an epoxy resin.

[0046] In this example, the shim 320 extends over a first length L1 on the lower surface 341 of the blade 340 and over a second length L2 on the upper surface 342 of the blade 340. The shim 320 is therefore asymmetrical with respect to the axis extending between the leading edge 350 and the trailing edge of the blade 300. In this example, the folds 331, 332, and 333 extend over the same lengths L1 and L2 on the lower surface 341 and upper surface 342 of the blade 300. However, they can also extend over lengths greater than L1 for the lower surface 341 and greater than L2 for the upper surface 342 of the blade 340, which helps to protect the blade 340 during assembly. and / or the removal of the 320 shim during the manufacture or repair of the blade 300. The lengths L1 and L2 can also vary on the height of the blade 300 and reverse in terms of proportions, i.e. L1 can be greater than L2 and vice versa.

[0047] The 330 plies plurality, for example, has a thickness between 0.2 mm and 1 mm, and the 320 metallic slush between 0.1 mm and 0.5 mm.

[0048] Regardless of the method of implementation, in order to fix the tinplate to the blade, a film of glue may also be present between the metallic tinplate and the unidirectional fabric folds.

[0049] Regardless of the method of implementation, in order to fix the shims to the blade, one can co-fire the metallic shims with the blade including the blade and the unidirectional fabric folds after draping the fabric folds.

[0050] Regardless of the method used, to fix the fabric folds to the raft, the folds, which are pre-impregnated with resin, can be draped together. During baking, the resin in the pre-impregnated folds will polymerize and harden.

[0051] Regardless of the embodiment of the invention, the material forming the metallic shim may comprise an alloy of titanium and / or aluminum.

[0052] Regardless of the embodiment of the invention, the composite material of the unidirectional fabric plies comprises Kevlar fibers. The advantage of Kevlar is its high impact resistance, which helps protect the blade, for example, in the event of a bird strike.

[0053] Regardless of the specific embodiment of the invention, the blade can be a three-dimensional component produced by weaving three-dimensional fibers. For example, it can be woven from organic fibers, such as carbon fibers, or glass fibers. The fibers are then densified by a matrix, which can be organic in nature.

[0054] Regardless of its specific embodiment, the blade can constitute an outlet guide vane, an inlet guide vane, a fan blade, or a variable-pitch blade. More specifically, the blade can constitute any fan blade at the low-pressure compressor of a turbomachine.

[0055] The invention also relates to a method for repairing a blade according to the invention. figure 4 shows the different stages of an example of a repair process according to the invention.

[0056] The first step in the process, 401, is to remove the metallic shim from the blade. This shim may, for example, be damaged as a result of blade use. To remove the shim, one can, for example, peel it off.

[0057] In a second step 402, the surface of the new metallic shim is prepared.

[0058] In a third step 403, a new shim is positioned and assembled on the leading edge of the blade. The new shim can be assembled onto the unidirectional fabric plies by bonding, or by co-curing the new shim, the fabric plies, and the blade. Co-curing is carried out, for example, in an autoclave so that the resin polymerizes throughout the entire part.

[0059] The expression "between ... and ..." should be understood as including the boundaries.

Claims

1. A turbomachine blade (100, 200, 300) comprising a blading (140, 240, 340) made of composite material with a fibrous reinforcement densified by a matrix, the fibrous reinforcement being derived from a three-dimensional fiber weaving, and a metal leading edge (150, 250, 350) formed by a metal foil (120, 220, 320), the foil having an intrados fin (221) and an extrados fin (222) which extend respectively over intrados (241, 341) and extrados (242, 342) faces of the blading by conforming to an airfoil of the blade, characterized in that the blade also comprises at least one unidirectional fabric ply (230, 331, 332, 333) made of composite material on the leading edge between the blading and the metal foil, each fabric ply extending at least partially over the intrados and extrados faces of the blading.

2. The turbomachine blade according to claim 1, wherein the metal foil extends over a first length (L1) on the intrados face of the blading and over a second length (L2) on the extrados face of the blading.

3. The turbomachine blade according to claim 2, wherein the first and second lengths are equal.

4. The turbomachine blade according to any one of claims 1 to 3, wherein each unidirectional fabric ply extends over an entire inner surface of the intrados and extrados fins of the foil.

5. The turbomachine blade (300) according to any one of claims 1 to 4, wherein the blade comprises a plurality (330) of unidirectional fabric plies (331, 332, 333) made of composite material on the leading edge between the metal foil and the blading, the plies of the plurality of fabric plies being draped over each other and extending over the intrados (341) and extrados (342) faces of the blading (340) by conforming to the airfoil of the blade.

6. The turbomachine blade according to any one of claims 1 to 5, wherein an adhesive film is present between said at least one unidirectional fabric ply and the metal foil.

7. The turbomachine blade according to any one of claims 1 to 6, wherein the metal foil has a thickness comprised between 0.1 mm and 0.5 mm on the intrados and extrados faces.

8. The turbomachine blade according to any one of claims 1 to 7, wherein said at least one unidirectional fabric ply has a thickness comprised between 0.15 mm and 0.25 mm.

9. The turbomachine blade according to any one of claims 1 to 8, constituting an outlet guide vane, an inlet guide vane, a fan blade or a variable-pitch blade.

10. A method for repairing a turbomachine blade according to any one of claims 1 to 9, comprising the removal of the metal foil (401), the preparation of a surface of new metal foil (402) and the positioning of said new metal foil on the at least one unidirectional fabric ply (403).