A TURBOMACHINE SPINNING WITH WEAR-RESISTANT PROTECTION

Abstract

The invention relates to a turbine blade (8) for an aircraft turbomachine (1), the blade (8) comprising: - a body having a blade (14) and a foot (15) connected to the blade (14) by a strut (16), the body being made of a composite material comprising a matrix and fibers embedded in the matrix, and - a wear protection (17) arranged on the strut (16) and / or the foot (15) of the body, characterized in that the wear protection (17) comprises a metallic substrate (19) arranged on the strut (16) and / or the foot (15), and a wear-resistant coating (20) arranged on the metallic substrate (19). Abstract figure: Figure 3

Description

Title of the invention: TURBOMACHINE BLADE COMPRISING ANTI-WEAR PROTECTION Technical field of the invention

[0001] The invention relates to the field of turbine blades for aircraft turbomachinery. The invention is more particularly related to the field of turbine blades comprising a body made of composite material and wear protection.

[0002] The invention also relates to the field of manufacturing and repairing these blades. Technical background

[0003] An aircraft turbomachine, such as a turbojet, typically comprises, from upstream to downstream in the direction of gas flow, a movable fan rotating about a longitudinal axis, a low-pressure compressor and a high-pressure compressor, a combustion chamber, a high-pressure turbine and a low-pressure turbine and a gas exhaust nozzle.

[0004] The blower allows the intake of an airflow that splits into a primary flow and a secondary flow. The primary flow passes through a primary channel of the turbomachine while the secondary flow is directed towards a secondary channel surrounding the primary channel.

[0005] The primary flow is compressed within the compressors. The compressed air is then mixed with a fuel and burned within the combustion chamber. The expanding gases expelled from the combustion chamber pass through the turbines and then escape through the nozzle, the cross-section of which allows these gases to be accelerated to generate propulsion.

[0006] The rotor of the low-pressure turbine is, for example, connected to the rotor of the low-pressure compressor by a low-pressure shaft, and the rotor of the high-pressure turbine is connected to the rotor of the high-pressure compressor by a high-pressure shaft. Furthermore, the blower typically comprises a blower disc centered on the longitudinal axis and connected to the low-pressure shaft, for example, by a blower shaft, for its rotational drive. The blower also comprises blades mounted regularly around the blower disc.

[0007] The blades typically comprise a body with a blade and a foot connected to the blade by a strut. The foot is housed in a recess in the disk in order to retain the blade on the disk when the turbomachine is in operation.

[0008] The blade body is also made of a composite material comprising a matrix and fibers embedded in the matrix, while the disc is typically metallic. The stilt and / or the foot of the composite material body are thus in contact with the disc which is made of metallic material. This contact generates friction leading to wear of the body, in particular of the stilt and / or foot which can cause irreversible damage to the composite material and impact the integrity of the blade.

[0009] In order to limit damage to the blade body, document WO-Al-2021 / 198621 proposes a blade comprising a body made of composite material and including a blade and a foot connected to the blade by a strut. The blade further includes wear protection to prevent friction, arranged on the strut and / or the foot of the body. According to this document, the wear protection is a strip of fabric attached to the strut and / or the foot.

[0010] Although this solution significantly reduces premature blade wear due to friction, it is not entirely satisfactory. Indeed, it has been observed that the lifespan of such a fabric strip is limited. Therefore, it is necessary to replace and / or repair the strip during the blade's service life. Replacing and / or repairing such a strip is not easy, as it requires working on the blade body made of composite material. Typically, replacement and / or repair requires heating the blade to a temperature between 100°C and 160°C for a period of one to four hours, thus reducing the blade's lifespan, as it cannot withstand repeated heating cycles.

[0011] Also, since such strips are directly attached to the blade body, they must exhibit sufficient adhesion to the blade body. The types of strips that can be used are therefore limited.

[0012] Moreover, the fabric strips have a high cost, which increases the cost of manufacturing a vane.

[0013] Therefore, there is a need to provide a blade comprising a body made of composite material including a matrix and fibers embedded in the matrix and a reliable wear protection, easy to maintain, which can be restored without impact on the blade body and which is inexpensive. Summary of the invention

[0014] To this end, the invention proposes a blade for an aircraft turbomachine, the blade comprising:

[0015] - a body comprising a blade and a foot connected to the blade by a stilt, the body being made of a composite material comprising a matrix and fibers embedded in the matrix, and

[0016] - an anti-wear protection arranged on the stilt and / or the foot of the body.

[0017] The dawn is remarkable in that the wear protection comprises a metallic substrate arranged on the stilt and / or the foot, and a wear-resistant coating arranged on the metallic substrate.

[0018] The blade according to the invention is intended to be mounted on a blower disc which is metallic.

[0019] The anti-wear protection helps to limit wear on the foot and / or the stilt.

[0020] The wear protection according to the invention comprises a superposition of layers comprising a metal substrate mounted on the Péchasse and / or the foot. The metal substrate is coated with an anti-wear coating designed to reduce the coefficients of friction between the two opposing parts and to protect the foot and / or Péchasse from repeated friction with the blower disc.

[0021] Applying a coating is more advantageous on a metallic substrate than on a composite material layer. Indeed, the metallic substrate allows for the application of any type of coating to the stilt and / or the foot. This expands the coating's functionality. Furthermore, the presence of the metallic substrate improves the adhesion of the wear-resistant coating to the composite body. In fact, the substrate can be chosen to enhance the wear-resistant coating's adhesion to the body.

[0022] In addition, it is possible to carry out the reconditioning, the restoration of the wear protection by simply removing the coating without having to act on the body of the blade or the bonding of the metallic substrate.

[0023] Furthermore, in the event of premature wear of the coating and before its repair, the integrity of the blade body is ensured by the presence of the metallic substrate.

[0024] Finally, thanks to the invention, it is possible to do away with the costly strips of fabric from the front part.

[0025] The invention may comprise one or more of the following features, taken individually or in combination with each other:

[0026] - the coating has a thickness of less than 1 mm, for example between 0.1 mm and 0.5 mm,

[0027] - the coating is made of a metallic material selected from copper alloys and of aluminium, nickel and aluminium alloys, and is for example a CoCrAlYSi-hBN alloy or a CuNiLn alloy,

[0028] - the metallic substrate is made of titanium or titanium alloy,

[0029] - the wear protection further comprises a layer of sliding varnish arranged on the coating, the varnish layer includes, for example, molybdenum disulfide particles,

[0030] - the wear protection has an elongated shape and extends from one end of the foot and / or of Péchasse located on the leading edge of the blade, at an opposite end of the foot and / or of Péchasse located on the trailing edge of the blade,

[0031] - the metallic substrate is glued onto the stilt and / or the foot.

[0032] The invention also relates to a method for manufacturing a blade according to one of the preceding characteristics, comprising the following steps:

[0033] (100) provide a body made of composite material comprising a matrix and fibers embedded in the matrix, the body comprising a blade connected to a foot by a stilt,

[0034] (300) arrange a metallic substrate on the stilt and / or the foot of the body, and

[0035] (500) deposit an anti-wear coating on the metallic substrate.

[0036] The manufacturing process may include one or more of the following features, taken individually or in combination with each other:

[0037] - the coating is deposited by thermal spraying and the metallic substrate is bonded on the stilt and / or the foot

[0038] - during the thermal projection step (500), the temperature of the blade body is lower than the glass transition temperature of the metal substrate bonding material.

[0039] The invention also relates to a method for repairing a blade according to any one of the preceding characteristics, the method comprising the following steps:

[0040] (100') remove the coating,

[0041] (200') mechanically treat the metallic substrate, and

[0042] (300') deposit a sound anti-wear coating on the metallic substrate.

[0043] The repair method may include one or more of the following features, taken individually or in combination with each other:

[0044] - at step (100'), the coating is removed by water jet blasting, and / or

[0045] - at step (300'), the sound anti-wear coating is deposited by thermal spraying. Brief description of the figures

[0046] Other features and advantages will become apparent from the following description of a non-limiting embodiment of the invention with reference to the accompanying drawings in which:

[0047] [Fig. 1] is a schematic longitudinal cross-sectional representation of half an aircraft turbomachine,

[0048] [Fig.2] is a perspective view of a blower equipping the turbomachine of [Fig.1], and comprising a blade according to the invention mounted on a disk,

[0049] [Fig.3] is a schematic view of the dawn of [Fig.2],

[0050] [Fig. 4] is a cross-sectional view of the foot and / or stilt of the dawn of the [Fig.3],

[0051] [Fig. 5] is a block diagram of a method for manufacturing a blade according to the invention,

[0052] [Fig. 6] is a synoptic diagram of a method for repairing a blade according to the invention,

[0053] [Fig.7] is an optical microscope image of an anti-wear protection according to the invention deposited on a composite layer. Detailed description of the invention

[0054] An example of an aircraft turbomachine 1 according to the invention is shown in [Fig. 1]. The turbomachine 1 extends around and along a longitudinal axis X.

[0055] In the present application, the terms "axial" and "axially" are defined with respect to the longitudinal axis X.

[0056] The terms "upstream" and "downstream" are defined with respect to the direction of gas flow in the turbomachine 1 along the longitudinal axis X.

[0057] The terms "radial", "radially", are defined with respect to a radial axis Z which is perpendicular to the longitudinal axis X of the turbomachine 1.

[0058] The terms "internal", "interior", "external", "outside", "externally" are defined with respect to the distance from the longitudinal axis X along the radial axis Z.

[0059] The turbomachine 1 comprises, from upstream to downstream, a blower 2, at least one compressor such as a low-pressure compressor 3 and a high-pressure compressor 4, a combustion chamber 5, at least one turbine such as a high-pressure turbine 6 and a low-pressure turbine 7, and a nozzle for exhausting the gases.

[0060] The blower 2 allows the aspiration of an air flow F which divides into a primary flow Fl and a secondary flow F2. The primary flow Fl passes through a primary channel of the turbomachine 1 while the secondary flow F2 is directed towards a secondary channel surrounding the primary channel.

[0061] The primary flow Fl is compressed within the low pressure compressor 3 and then the high pressure compressor 4. The compressed air is then mixed with a fuel and burned within the combustion chamber 5. The gases produced by the combustion pass through the high pressure turbine 6 and low pressure turbine 7. The gases finally escape through the nozzle whose cross-section allows the acceleration of these gases to generate propulsion.

[0062] The rotor of the low-pressure turbine 7 is, for example, connected to the rotor of the low-pressure compressor 3 by a low-pressure shaft. The rotor of the high-pressure turbine 6 is, in turn, connected to the rotor of the high-pressure compressor 4 by a high-pressure shaft. The low-pressure shaft is arranged coaxially inside the high-pressure shaft and extends along the longitudinal axis X.

[0063] The fan 2 is, for example, enclosed. The turbomachine 1 then comprises a annular nacelle 11 centered on the longitudinal axis X surrounding the blower 2. The nacelle 11 is for example supported by a blower housing (not shown).

[0064] The blower 2 is mobile in rotation around the longitudinal axis X. It is driven in rotation for example by a blower shaft which is connected to the low pressure shaft, for example via a mechanical speed reducer.

[0065] As more clearly seen in [Fig.2], the blower 2 comprises blades 8 regularly distributed around a disk 9 centered on the longitudinal axis X. The disk 9 comprises an annular body 12 having alveoli 13 formed in the annular body 12. There are as many alveoli 13 as there are blades 8.

[0066] The blades 8 extend radially around the disk 9. The blades 8 comprise a body having a blade 14 and a foot 15. The blade 14 is connected to the foot 15 by a strut 16. The body is made of composite material comprising a matrix and reinforcing fibers embedded in the matrix.

[0067] The matrix is, for example, an organic matrix. For example, the matrix is ​​made of a polymeric material chosen from thermoplastics, for example, polypropylene, polyethylene, or thermosets, for example, an epoxy polymer, phthalonitrile, polybismaleimide, polyimide.

[0068] The fibers are, for example, carbon fibers, glass fibers or any fiber suitable for the present application.

[0069] The blade 14 has an aerodynamic shape. It comprises an intrados face 14a and an extrados face 14b, which are connected by a leading edge and a trailing edge 14c. Preferably, the leading edge is covered by a metallic shield 14d. The shield 14d has a general trihedral shape. It has a V- or U-shaped cross-section. The shield 14d comprises a first fin extending over the intrados face 14a and a second fin extending over the extrados face 14b. The first and second fins are connected by a central portion covering the leading edge.

[0070] The foot 15 has a tenon shape. It is inserted into the socket 13 of the disc 9. The stilt 16 is arranged radially between the foot 15 and the blade 14.

[0071] The blade body 8 is formed by resin transfer molding (RTM). Alternatively, the blade body 8 is formed by draping. The shield 14d is, for example, attached to the blade 14 during or after the molding of the blade 14.

[0072] The awl 8 further includes an anti-wear protection 17. The anti-wear protection 17 is arranged on a surface of the foot 15 and / or of the stilt 16.

[0073] The wear protection 17 has an elongated shape. It extends from one end of the foot 15 and / or the strut 16 located on the leading edge side of the blade 14 to an opposite end of the foot 15 and / or the strut 16 located on the trailing edge side. 14b.

[0074] The wear protection 17 has a total thickness of between 0.1 mm and 2 mm, preferably between 0.1 mm and 1 mm, for example between 0.1 mm and 0.2 mm. Such a thickness is particularly advantageous because it protects the foot 15 and the stilt 16 from premature wear while allowing the foot 15 to be mounted in the recess 13 of the disc 9. Indeed, below this thickness, the wear protection would be insufficient, and above this thickness, the foot 15 could no longer be inserted into the recess 13 without resizing the recess 13 or even the disc 9.

[0075] As illustrated in Figures 3 and 4, the wear protection 17 is multilayered. From the inside out, with the inside located on the side of the foot 15 or the stilt 16, it comprises optionally a layer of adhesive 18, a metallic substrate 19 arranged on the foot 15 and / or the stilt 16, and a wear-resistant coating 20 applied by various methods. Optionally, the wear protection 17 further comprises a layer of sliding varnish 21 arranged on the coating 20. In this example, the varnish layer 21 is, for instance, the outermost layer.

[0076] The adhesive layer 18 is, for example, made of a polymer material. The glass transition temperature of the polymer is, for example, between 100°C and 250°C, preferably between 150°C and 200°C. The material is, for example, selected from epoxy polymers. The adhesive layer 18 has a thickness, for example, between 20 µm and 400 µm, preferably between 70 µm and 350 µm.

[0077] The metal substrate 19 is preferably bonded to the foot 15 and / or the stilt 16 by the adhesive layer 18. The adhesive layer 18 is therefore arranged between the metal substrate 19 and the foot 15 and / or the stilt 16. The metal substrate 19 has a thickness of less than 1 mm, preferably between 0.1 mm and 0.5 mm, and even more preferably between 0.1 mm and 0.2 mm. The metal substrate 19 is, for example, made of titanium or a titanium alloy such as the TA6V titanium alloy.

[0078] The metallic substrate 19 is arranged between the adhesive layer 18 and the coating 20. The coating 20 is advantageously made of a metallic material. The metallic material is, for example, selected from copper-aluminum alloys (CuAl), nickel-aluminum alloys (NiAl), and is, for example, a CoCrAlYSi-hBN alloy or a CuNiLn alloy. The coating 20 has a thickness of less than 1 mm, preferably between 0.1 mm and 0.5 mm, between 0.1 mm and 0.2 mm, and even more preferably between 0.13 mm and 0.19 mm. The coating 20 is advantageously deposited by thermal spraying, such as plasma spraying.

[0079] The varnish layer 21 has a thickness, for example, of between 5 µm and 40 µm, preferably between 10 µm and 40 µm. The varnish layer 21 comprises, for example, an organic matrix and lubricating particles distributed within the matrix. The organic matrix is, for example, chosen from thermosetting polymers such as epoxy polymers. The lubricating particles are, for example, molybdenum disulfide (MoS2), graphite, or polytetrafluoroethylene (PTFE) particles. Preferably, the varnish layer 21 comprises an epoxy polymer matrix and molybdenum disulfide particles distributed within the matrix.

[0080] The wear protection 17 helps to limit wear on the blade 8 caused by friction between the metal disc 9 and the composite blade body 8. The varnish layer 21 further reduces friction between the blade body 8 and the disc 9 by helping to lower the coefficient of friction at the contact area.

[0081] The metallic substrate 19 allows the application of the coating 20 without affecting the integrity of the blade body 8. Typically, when the metallic substrate 19 is made of titanium or a titanium alloy and when the coating 20 is applied by thermal spraying, the thermal conductivity of titanium is sufficiently low to limit heat transfer to the blade body 8 during the application of the coating 20, for example, by thermal spraying. It also improves the adhesion of the coating to the blade body 8. Furthermore, thanks to the metallic substrate 19, it is also possible to deposit a coating of any type. Indeed, the coating 20 can have thermal conductivity properties to promote de-icing, for example, tribological properties, and / or anti-erosion properties. Also, in the event of degradation of the wear protection 17, it is sufficient to remove the degraded coating 20.The metallic substrate 19 therefore allows the replacement of the coating 20 without direct action on the blade body 8.

[0082] A manufacturing process for the blade 8 will now be described with reference to [Fig.5].

[0083] The process includes a first step 100 of supplying the blade body 8. According to a first example, the supply 100 is carried out by resin transfer molding. According to this example, the supply step includes a first substep of supplying a fibrous preform followed by a substep of injecting a resin to densify the fibrous preform. The injection is, for example, carried out in a mold.

[0084] According to a second example, supply 100 is made by draping.

[0085] The method may include an optional step of fixing the shield 14d.

[0086] According to a first example, the attachment of the shield 14d is carried out during step 100 when the body is produced by molding. For example, the shield 14d can be arranged in the mold before the resin injection substep. Then the injection substep is carried out, allowing the densification of the preform and the attachment of the shield. shield mutanée 14d.

[0087] Alternatively, the shield 14d can be fixed to the body after step 100. A layer of glue is for example applied to the leading edge and then the shield 14d is fixed to the body.

[0088] The process further includes a step of arranging the metallic substrate 19 on the foot 15 and / or stilt 16. This step is carried out for example by gluing the metallic substrate 19 onto the foot 15 and / or stilt 16.

[0089] According to a first example, the bonding step of step 300 is carried out during the supply step 100. For example, the metal substrate 19 can be arranged in the mold before the injection substep. Then, the resin is injected, allowing the densification of the preform and the simultaneous fixation of the metal substrate 19.

[0090] Alternatively, the gluing step of step 300 is carried out after step 100. According to this example, the glue layer 18 is first applied to Péchasse 16 and / or the foot 15 and then the metal substrate 19 is glued.

[0091] Optionally, prior to the bonding step 300, the process may include a treatment step 200 of the metal substrate 19. The treatment is preferably chemical. For example, the metal substrate 19 is subjected to chemical treatment in an alkaline bath such as BONDERITE C-AK 5578-GL from HENKEL. This improves the bonding of the metal substrate 19 to the blade body 8. A bonding primer may also be applied to the metal substrate 19 as a complement to, or alternative to, the chemical treatment. The bonding primer is, for example, EC3918 from 3M. This further improves the bonding of the metal substrate 19 to the blade body 8.

[0092] Advantageously, the process comprises, after the bonding step 300, a mechanical treatment step 400 of the metal substrate 19. The mechanical treatment is, for example, sandblasting. During sandblasting, an abrasive is projected onto the metal substrate 19. The abrasive comprises, for example, particles having a particle size between 50 µm and 500 µm, preferably between 100 µm and 300 µm. The particles are, for example, white corundum of the F70 or F46 series.

[0093] The process further includes a step 500 of the coating 20 on the metallic substrate 19.

[0094] According to a first example, the deposition step 500 is carried out after the bonding step 300 and the optional mechanical treatment step 400. According to this example, preferably, the deposition step 500 is carried out by thermal spraying. The thermal spraying process is, for example, plasma spraying. During the thermal spraying of the coating 20, the temperature of the blade body 8 is maintained below the glass transition temperature of the matrix. Preferably, the temperature of the blade body 8 is maintained below 120°C, and even more so a temperature less than or equal to 75°C. This helps to preserve the integrity of the blade 8 during the deposition of the coating 20.

[0095] According to a second example, the deposition step 500 is carried out before the bonding step 300. According to this example, the deposition is carried out by physical vapor deposition (PVD).

[0096] Optionally, particularly when the coating 20 is deposited by thermal spraying, the process includes, after the deposition step 500, an application step 600 of the sliding varnish.

[0097] The process according to the invention is fully automatable.

[0098] A method for repairing the blade 8 will now be described with reference to the [Fig. 6]. The repair process includes the following steps:

[0099] - 100' removal of coating 20,

[0100] - mechanical treatment 200' of the metallic substrate 19, and

[0101] - deposition of a healthy anti-wear coating 300' on the metallic substrate 19.

[0102] The 100' removal step can be carried out by water jet blasting.

[0103] The mechanical treatment step 200' can be carried out by sandblasting.

[0104] The step of depositing the healthy anti-wear coating 300' can be carried out by thermal spraying.

[0105] The repair process according to the invention therefore involves steps that are carried out without any impact on the blade body 8. In particular, no heat treatment step for the blade 8 is required. Consequently, the repair process can be repeated a large number of times. Examples

[0106] A test specimen was produced to evaluate the strength of the composite body during the manufacturing process, the integrity of the blade and the adhesion of the wear protection to the body.

[0107] The test specimen has a 4 mm thick composite material layer and a 0.4 mm thick TA6V titanium alloy metal substrate bonded to the composite material layer with an epoxy adhesive film. A 140 µm thick nickel-aluminum alloy (NiAl) coating was sprayed onto the metal substrate.

[0108] Example 1: Body posture

[0109] Temperature indicators were placed on the test specimen. The temperature of the composite layer is maintained below 75°C.

[0110] Example 2: Dawn integrity

[0111] An observation of the test specimen under an optical microscope was carried out and is shown in [Fig. 7]. The results show that there was no decohesion of the wear protection. No degradation of the composite layer occurred between the layers of the wear protection and between the composite layer and the wear protection. No degradation of the composite layer was observed.

[0112] Example 3: membership

[0113] A pull-out test was performed on the specimen. The breaking strength was 33 MPa, with failure occurring between the adhesive layer and the metallic substrate. The coating therefore exhibits good adhesion to the metallic substrate.

Claims

Demands

1. A method for manufacturing a blade (8) for an aircraft turbomachine, the method comprising the following steps: (100) providing a body of composite material comprising a matrix and fibers embedded in the matrix, the body having a blade (14) connected to a foot (15) by a strut (16), (300) bonding a metallic substrate (19) to the strut (16) and / or the foot (15) of the body, and (500) depositing an anti-wear coating (20) on the metallic substrate (19), characterized in that the coating (20) is deposited by thermal spraying or by physical vapor deposition before step (300).

2. A method according to the preceding claim, characterized in that, during the thermal spraying step (500), the temperature of the blade body (8) is lower than the glass transition temperature of the bonding material of the metallic substrate (19).

3. A method for repairing a blade (8) for an aircraft turbomachine (1), the blade (8) comprising: - a body having a blade (14) and a foot (15) connected to the blade (14) by a strut (16), the body being made of a composite material comprising a matrix and fibers embedded in the matrix, and - a wear protection (17) arranged on the strut (16) and / or the foot (15) of the body, the wear protection (17) comprising a metallic substrate (19) arranged on the strut (16) and / or the foot (15), and a wear-resistant coating (20) arranged on the metallic substrate (19), characterized in that the repair method comprises the following steps: (100') removing the coating (20), (200') mechanically treating the metallic substrate (19), and (300') depositing a sound wear-resistant coating on the metallic substrate (19) by thermal projection.

4. Repair method according to the preceding claim, characterized in that: - at step (100'), the coating (20) is removed by water jet blasting.

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