Method for repairing a propeller blade of a turbomachinery

Abstract

A method of repairing a turbomachine rotor, particularly a turbomachine fan blade (10), the blade comprising an organic matrix composite vane (12) and a metal shield (14) bonded to a leading edge of the vane, the metal shield (14) having a damaged area (20), the method comprising the steps of resetting the leading edge of the vane, cooling the entire vane, refilling the damaged area (20) by adding metallic material to the damaged area (20) and melting the material using a laser, and finishing the damaged area (20) by machining the molten material.

Description

[Technical field]

[0001] The present invention relates to a method for repairing the propeller blades of a turbomachine, and in particular the fan of said turbomachine. [Background technology]

[0002] The prior art includes in particular the documents EP 3045260 A1, DE 102010006384 A1 and FR 3046557 A1.

[0003] An aircraft turbomachine includes one or more propellers which may be ducted or unducted. The invention applies in particular to the blades of fans, i.e. the blades of ducted propellers, but also to other types of propellers, for example the unducted propellers of turboprop engines.

[0004] Turbomachinery propellers are traversed by the airflow and their blades can become damaged by abrasion or impact, for example FOD (Flying Object Damage) type damage caused by birds impacting the blades.

[0005] The present invention relates to repairing a propeller blade having a damaged area, and more particularly to repairing a propeller blade having an organic matrix composite (OMC) vane and a metal shield bonded to the leading edge of the vane.

[0006] In a known manner, the OMC vane may comprise a woven preform embedded in a polymer matrix, the preform being obtained by weaving carbon fibres in three dimensions.

[0007] The shield, as described in application FR 3 046 557, comprises two lateral wings extending respectively on the pressure and suction sides of the vane, and a nose connecting the two wings. These two lateral wings and this nose, which are particularly exposed to the flow of gas passing the propeller, are particularly at risk of wear, due to abrasion, impact or erosion. In particular, the nose, which faces the upstream side of the turbomachine and forms the leading edge of the propeller through which the gas flow passes during operation, is most exposed to the risk of damage. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] European Patent Application Publication No. 3045260 [Patent Document 2] DE 102010006384 A1 [Patent Document 3] French Patent Application Publication No. 3046557 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention provides a simple, effective and economical solution for repairing propeller blades of this type. [Means for solving the problem]

[0010] The present invention proposes a method for repairing a turbomachine propeller blade, in particular a turbomachine fan blade, comprising a vane made of an organic matrix composite and a metal shield bonded to the leading edge of the vane, the metal shield having a damaged area, comprising the steps of adding metallic material to the damaged area and laser melting the material to replenish the damaged area, and finishing the metallic area by machining the molten material.

[0011] The invention thus proposes to repair the shield of a blade in situ, i.e. without dismantling or removing it from the blade, which is particularly advantageous since it simplifies and accelerates the repair of this type of blade and avoids scrapping the blade when the shield is damaged but remains repairable.

[0012] According to the invention, before said refilling and finishing steps, the method comprises the steps of resetting the leading edge of the vane and cooling the entire vane.

[0013] By adding a step of resetting the leading edge upstream of the step of refilling the damaged area, the actual profile (or geometry) of the damaged leading edge can be measured precisely. Indeed, a blade after use in a turbomachine may be deformed (so-called blades with real profile) and therefore the dimensions of the blade after use will no longer correspond to the dimensions of a new blade immediately after production (so-called blades with theoretical profile). The method according to the invention therefore makes it possible to specifically repair the damaged area of ​​a blade according to the actual profile of its leading edge (which may have changed with respect to the theoretical profile). Moreover, this reset step makes it possible to precisely identify the damaged area of ​​the leading edge of the blade. This allows the refilling step to deposit the strictly required amount of material to the millimeter of the damaged area to be repaired.

[0014] By adding a step of cooling the vane before the refill step, the temperature of the leading edge of the vane can be controlled near the adhesive joint or the interface between the two materials (i.e. the metal shield at the leading edge and the vane made of the organic matrix composite). In fact, during the step of depositing and melting material on the damaged area of ​​the blade, the entire volume of the vane is cooled to maintain the vane at the maximum allowable temperature for the adhesive joint (perhaps 120°C). Thus, in general, the refill parameters to achieve laser melting of the material are optimized while avoiding local overheating and degradation of the vane.

[0015] The method according to the invention may comprise one or more of the following features and / or steps, taken separately from one another or in combination with one another: The reset step is performed before or simultaneously with the cooling step. The reset step is performed by a movable probe. The vanes are cooled to a temperature of +20 to -20°C, preferably 0 to -20°C. The metal shield has two side wings extending respectively to the pressure side and the suction side of the vane and a nose connecting the two wings, and the damaged area is located on the nose. - a temperature threshold is predefined, which corresponds to a maximum temperature tolerated by the adhesive and / or the vane, the laser melting is performed by a machine, the parameters of the machine being set to prevent the adhesive and / or the vane from reaching this threshold. -The threshold is 120°C. -The filling material is the same as the shielding material. -The filler material is TA6V. said filler is titanium carbide TiC; At least during the refilling step, the blade is held on the frame with the area facing upwards. -The area is cooled during the refilling process. -Cooling can be achieved by conduction, neutral gas at room temperature, cooled neutral gas, ejection of liquid or solid elements, etc. -Cooling is ensured by cryogenic or Peltier effect. Laser melting is performed by a movable laser head. The reset and refill steps are each performed by a single device comprising a probe and a laser head, which device is capable of pivoting, on the one hand, to bring the probe into contact with the leading edge of the vane during the reset step, and, on the other hand, to bring the laser head against said leading edge of the vane during the refill step. -Laser melting is done by LMD (Laser Metal Deposition) or μlaser.

[0016] Further features and advantages of the present invention will become apparent from the following detailed description which refers to the accompanying drawings. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic perspective view of a propeller blade for a turbomachine, and in particular a schematic cross-sectional view of a fan for a turbomachine. [Diagram 2] FIG. 2 is a schematic cross-sectional view of a shield of a blade as shown in FIG. [Diagram 3] FIG. 3 is a schematic perspective view of a portion of an apparatus for carrying out the method according to the invention. [Figure 4] FIG. 4 is a partial schematic perspective view of the apparatus of FIG. 3 with the reconfiguration step performed. [Diagram 5] FIG. 5 is a partial schematic perspective view of the apparatus of FIG. 3 with the refilling step performed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] 1 shows a propeller blade 10, particularly an aircraft turbomachine fan, comprising an organic matrix composite vane 12 and a metal shield 14 bonded to the leading edge.

[0019] The vane 12 further includes a trailing edge 16 opposite the leading edge, and a pressure side and a suction side extending between the leading and trailing edges of the vane.

[0020] The blade has a longitudinal axis of note A, one longitudinal end of the vane 12 is free and the opposite longitudinal end is connected to a root 18 for mounting the blade on a turbomachine rotor.

[0021] As can be seen from FIG. 2, the shield 14 has two lateral wings 14a extending respectively to the pressure side and the suction side of the vane 12, and a nose 14b connecting the two wings 14a.

[0022] The wings 14a, 14b define a cavity therebetween for receiving the leading edge of the vane 12 as well as an adhesive for attaching the shield to the vane.

[0023] The set of metal shields 14 is susceptible to damage and therefore has a damaged area 20. The shields 14 must then undergo a method for repair. In particular, the nose 14c is susceptible to damage as shown in Figure 2. However, this is only an example, and the present invention can be applied to any part of the metal shields 14 without distinction.

[0024] Advantageously, the damage region 20, including impact or wear, is located from the apex (or head) of the blade 10 to at least two-thirds of the total length of the vane. The length of the blade 10 is measured relative to its longitudinal axis A. More specifically, the region 20 extends from the apex of the blade 10 to a central portion of the shield 14 of the blade 10. This central portion may correspond to a curved portion of the aerodynamic profile of the leading edge of the blade 10.

[0025] Nose 14c is susceptible to damage and subsequent repair procedures.

[0026] The present invention proposes a method for repairing a damaged area 20 of a shield 14 of a propeller blade 10, the method comprising: (a) resetting the leading edge of the vane 12; (b) cooling the entire vane 12; (c) refilling region 20 by adding metallic material to region 20 and laser melting the material (ideally both the base and the filler); (d) finishing region 20 by machining the molten material; Equipped with.

[0027] The cooling step (b) may be carried out after or during the resetting step (a).

[0028] FIG. 3 shows an example of an apparatus 22 for carrying out the method according to the invention.

[0029] The device 22 comprises a frame 24 for fixing and positioning the blade 10. The blade 10 can be fixedly positioned in the device 22 by supports 23 for holding the blade 10. In this example, a number of supports 23 hold the root 18, the trailing edge 16 and the top of the blade 10. The blade 10 is positioned so that its axis A is substantially horizontal. The frame 24 may be designed so that the blade 10 can be movably mounted about the axis A and positioned so that the shield 14, and in particular its damaged area 20, faces upwards (preferably perpendicular to the laser head 26) as in the example shown.

[0030] 4, the system 22 includes a probe 27 that can be probed by touching the leading edge of the blade 10 to specifically locate the region 20. The probe 27 can contact the edge or top of the nose 14c of the shield 14 and / or the pressure and suction sides of the wings 14a, 14b of the shield 14. Without limitation, some points 27' to be sensed are shown in FIG.

[0031] The device 22 comprises a cooling system 30, preferably by conduction. In this example, in a non-limiting manner, the blade 10 is at least partially surrounded by the system 30. More specifically, the system 30 is arranged to specifically cool the leading edge of the blade.

[0032] With reference to Figure 5, the device 22 also comprises a laser head 26 configured to generate a laser beam focused on the region 20. Preferably, the head 26 comprises a system 28 for adding refill material to the region 20. The laser head 26 and the probe 27 are mobile. Advantageously, the laser head 26 and the probe 27 are arranged on the same arm 25 of the device 22 (visible in Figure 4). The arm 25 is a mobile device that can preferably be pivoted between 90 and 180° to bring either the laser head 26 or the probe 27 into view relative to the blade 10.

[0033] The filling material is preferably the same as the material of the shield 14, for example TA6V. Advantageously, the filling material is titanium carbide TiC.

[0034] The material is melted by a laser, more specifically by the LMD or microlaser method. LMD uses a continuous laser beam, while microlasers implement a pulsed beam. In the case of a continuous laser, the laser heats the base material and the filler material continuously. As a result, the heat accumulates in the same area and propagates through the base material. In the case of a pulsed laser, the laser "fires" in a dotted line, which is less invasive and allows you to control the area of ​​heat diffusion.

[0035] Precise control of the temperature of the shield 14 can be important to ensure the integrity of the blade 10, as the hotter the shield is, the more heat it can conduct to the adhesives and materials in the vane, potentially damaging them, for example by melting the adhesive and risking the shield becoming detached from the vane.

[0036] In practice, a temperature threshold is preferably predetermined, which corresponds to the maximum temperature tolerated by the adhesive and / or the vanes. The parameters of the laser head 26 and the cooling system 30 are preferably adjusted so that the adhesive and / or the vanes do not reach this threshold. This threshold is, for example, 120° C.

[0037] The cooling system 30 may be designed to cool the vanes 12 or blades 10 by cryogenics (for example by spraying with liquid CO2 or dry ice or a neutral gas cooled upstream in a spraying circuit) or by the Peltier effect. The cooling temperature is for example +20 to -20 °C, preferably 0 to 20 °C.

[0038] The present invention has several advantages. Rapid repair of blades to get them back in service as quickly as possible. Repair of blades returning from service by adapting them to their actual aerodynamic profile. There is no need to remove the shield and clean it to remove adhesive residue. Do not remove the shield to avoid pairing issues. Repairing parts with bi-materials (composite-metal materials) without the use of certain measures such as ovens, clean rooms, or vacuum equipment. Refilling the metal shield without changing the composite material (or the adhesive that allows bi-material assembly) thanks to the low energy used in the laser welding and cooling system. Limits shield deformation due to recharging. Extending the useful life of (potentially deformed) blades for new use in turbomachinery. Limit disposal of used blades.

Claims

1. 1. A method for repairing a turbomachine propeller, in particular a turbomachine fan blade (10), comprising a vane (12) made of an organic matrix composite and a metal shield (14) bonded to a leading edge of the vane, the metal shield (14) having a damaged area (20), the method comprising a refilling step of refilling the damaged area (20) by adding metallic material to the damaged area (20) and laser melting the material, a finishing step of finishing the damaged area (20) by machining the molten material, characterized in that, prior to the refilling and finishing steps, a resetting step of resetting a leading edge of the vane (12) in order to measure an actual profile of the damaged area (20) of the leading edge, and a cooling step of cooling the entire vane (12).

2. The method of claim 1 , wherein a reset step is performed prior to or simultaneously with the cooling step.

3. The method according to claim 1 or 2, wherein the reset step is performed by a movable probe (27).

4. A method according to any one of claims 1 to 3, wherein the vane (12) is cooled to a temperature of +20 to -20°C.

5. The method according to any one of claims 1 to 4, wherein the cooling is ensured by cryogenic temperatures or by the Peltier effect.

6. 6. The method according to claim 1, wherein the metal shield (14) comprises two lateral wings (14a, 14b) extending respectively on the pressure side and on the suction side of the vane and a nose (14c) connecting the two wings, and the damaged area (20) is located on the nose (14c).

7. 7. The method according to any one of claims 1 to 6, wherein a temperature threshold is predetermined, which corresponds to a maximum temperature tolerated by the adhesive and / or the vane, and the laser melting is performed by a machine whose parameters are set to prevent the adhesive and / or the vane from reaching this threshold.

8. The method of claim 7, wherein the threshold value is 120°C.

9. The method according to any one of the preceding claims, wherein the filling material is the same as the material of the shield.

10. The method of claim 9 , wherein the filler material is TA6V.

11. The method according to any one of claims 1 to 8, wherein the filler material is titanium carbide (TiC).

12. A method according to any one of the preceding claims, wherein during the refilling step at least the blade (10) is held on the frame (24) with the region (20) facing upwards.

13. The method according to any one of the preceding claims, wherein the laser melting is performed by a movable laser head (26).

14. 14. The method according to claim 13, wherein the resetting and refilling steps are performed by a single device (25) comprising a probe (27) and a laser head (26), respectively, the device (25) being capable of pivoting to bring the probe (27) into contact with the leading edge of the vane (12) during the resetting step, on the one hand, and the laser head (26) facing the leading edge of the vane (12) during the refilling step, on the other hand.

15. The method according to any one of claims 1 to 14, wherein the laser melting is performed by an LMD or μ laser.

16. A method for repairing a turbomachine propeller, in particular a turbomachine fan blade (10), comprising an organic matrix composite vane (12) and a metal shield (14) bonded to a leading edge of the vane, the metal shield (14) having a damaged area (20); The method includes a refilling step of refilling the damaged area (20) by adding metallic material to the damaged area (20) and laser melting the material, and a finishing step of finishing the damaged area (20) by machining the molten material; a reset step of resetting the leading edge of the vane (12) to measure an actual profile of the damaged area (20) of the leading edge, and a cooling step of cooling the entire vane (12), prior to the refilling and finishing steps; A method according to any one of claims 1 to 5, characterised in that the vanes (12) are cooled to a temperature of +20 to -20°C.

17. A method for repairing a turbomachine propeller, in particular a turbomachine fan blade (10), comprising an organic matrix composite vane (12) and a metal shield (14) bonded to a leading edge of the vane, the metal shield (14) having a damaged area (20); The method includes a refilling step of refilling the damaged area (20) by adding metallic material to the damaged area (20) and laser melting the material, and a finishing step of finishing the damaged area (20) by machining the molten material; a reset step of resetting the leading edge of the vane (12) to measure an actual profile of the damaged area (20) of the leading edge, and a cooling step of cooling the entire vane (12), prior to the refilling and finishing steps; A method, characterized in that the cooling is ensured by cryogenic temperatures or by the Peltier effect.

18. A method for repairing a turbomachine propeller, in particular a turbomachine fan blade (10), comprising an organic matrix composite vane (12) and a metal shield (14) bonded to a leading edge of the vane, the metal shield (14) having a damaged area (20); The method includes a refilling step of refilling the damaged area (20) by adding metallic material to the damaged area (20) and laser melting the material, and a finishing step of finishing the damaged area (20) by machining the molten material; a reset step of resetting the leading edge of the vane (12) to measure an actual profile of the damaged area (20) of the leading edge, and a cooling step of cooling the entire vane (12), prior to the refilling and finishing steps; 2. The method of claim 1, wherein the filler material is titanium carbide (TiC).

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