Aerofoil assembly and a method of manufacturing an aerofoil assembly

Abstract

An aerofoil assembly, for example a bladed rotor assembly (40B) comprises a rotor (42) carrying a plurality of rotor blades (44), at least one of the rotor blades (44) having a coating (46) on the surface of the rotor blade (44). At least one of the rotor blades (44) has a coating (46) having a different thickness, a different area of contact with the surface of the rotor blade (44), a different position of contact on the surface of the rotor blade (44), a different shape of contact on the surface of the rotor blade (44) and/or a different composition compared to at least one of the other rotor blades (44). The coating (46) is applied in a non-uniform manner to reduce the vibration level of the rotor blade (44), or rotor blades (44), with the highest vibration response for a given excitation by changing the bladed rotor assembly (40B) mode shapes and the relative vibration of the rotor blades (44).

Description

The present invention will be more fully described by way of example with reference to the accompanying drawings in which:—

FIG. 1 shows a turbofan gas turbine engine having a rotor blade assembly according to the present invention.

FIG. 2 shows an enlarged view of a bladed rotor assembly according to the prior art.

FIG. 3 shows an enlarged view of a bladed rotor assembly according to the present invention.

Claims

1. A method of manufacturing an aerofoil assembly comprising forming a structure carrying a plurality of aerofoils, the aerofoils having physical differences, exciting and measuring the vibration behaviour of each aerofoil, analysing the vibration behaviour of the aerofoils, determining where to add material to, or remove material from, the surface of at least one of the aerofoils and adding material to, or removing material from, the surface of at least one of the aerofoils of the aerofoil assembly is in a non-uniform manner to reduce the vibration level of the aerofoil, or aerofoils, with the highest vibration for the given excitation by changing the aerofoil assembly mode shapes and the relative vibration of the aerofoils.

2. A method as claimed in claim 1 comprising adding material on, or removing material from, the surface of at least one of the aerofoils differently compared to at least one of the other rotor aerofoils.

3. A method as claimed in claim 1 comprising forming a stator carrying a plurality of stator vanes, the stator vanes having physical differences, adding material on, or removing material from, the surface of at least one of the stator vanes differently compared to at least one of the other stator vanes.

4. A method as claimed in claim 1 comprising forming a rotor carrying a plurality of rotor blades, the rotor blades having physical differences, adding material on, or removing material from, the surface of at least one of the rotor blades differently compared to at least one of the other rotor blades.

5. A method as claimed in claim 4 comprising applying a coating on the surface of at least one of the rotor blades, applying a coating on the surface of at least one of the rotor blades such that the coating having a different thickness, a different area of contact with the surface of the rotor blade, a different position of contact on the surface of the rotor blade, a different shape of contact on the surface of the rotor blade and/or a different composition compared to at least one of the other rotor blades.

6. A method as claimed in claim 5 comprising applying a coating to a plurality of the rotor blades.

7. A method as claimed in claim 6 comprising applying a coating to all of the rotor blades.

8. A method as claimed in claim 5 comprising applying a coating to all of the surfaces of all of the rotor blades and removing coating from at least one of the rotor blades.

9. A method as claimed in claim 5 comprising applying a coating on a surface of a plurality of the rotor blades, the coating on the plurality of rotor blades having a different thickness, a different area of contact with the surface of the rotor blade, a different position of contact on the surface of the rotor blade, a different shape of contact on the surface of the rotor blade and/or a different composition compared to at least one of the other rotor blades.

10. A method as claimed in claim 9 comprising applying a coating on a surface of a plurality of the rotor blades, the coating on the plurality of rotor blades having a different thickness, a different area of contact with the surface of the rotor blade, a different position of contact on the surface of the rotor blade, a different shape of contact on the surface of the rotor blade and/or a different composition compared to a plurality of the other rotor blades.

11. A method as claimed in claim 10 comprising applying a coating on a surface of each of the rotor blades, the coating on each of the rotor blades having a different thickness, a different area of contact with the surface of the rotor blade, a different position of contact on the surface of the rotor blade, a different shape of contact on the surface of the rotor blade and/or a different composition compared to all of the other rotor blades.

12. A method as claimed in claim 5 comprising exciting each individual rotor blade and measuring the vibration behaviour of the individual rotor blade before assembling the rotor blades into the rotor assembly.

13. A method as claimed in claim 5 comprising constraining all of the rotor blades except for one unrestrained rotor blade, exciting the unrestrained rotor blade, measuring the vibration behaviour of the unrestrained rotor blade and repeating for each rotor blade.

14. A method as claimed in claim 5 comprising constraining the rotor so as to minimise rotor blade interaction, exciting the rotor blades and measuring the vibration behaviour of each rotor blade.

15. A method as claimed in claim 3 comprising analysing the measured vibration behaviour of the rotor blades, determining where to apply coatings to the rotor assembly such that the coating is applied in a non-uniform manner to reduce the vibration level of the rotor blade, or rotor blades, with the highest vibration response for a given excitation by changing the bladed rotor assembly mode shapes and the relative vibration of the rotor blades.

16. A method as claimed in claim 5 wherein the rotor carrying a plurality of radially outwardly extending rotor blades.

17. A method as claimed in claim 5 wherein the rotor blades being integral with the rotor.

18. A method as claimed in claim 17 comprising securing the rotor blade using a method selected from the group comprising friction welding, laser welding and diffusion bonding.

19. A method as claimed in claim 17 comprising machining the rotor blades and rotor from a solid member.

20. A method as claimed in claim 5 wherein the rotor blades having roots, the rotor having a plurality of slots in the periphery of the rotor and the roots of the rotor blades locating in the slots in the periphery of the rotor.

21. A method as claimed in claim 5 wherein the rotor is selected from the group comprising a disc and a drum.

22. A method as claimed in claim 5 wherein the rotor is selected from the group comprising a fan rotor, a compressor rotor and a turbine rotor.

23. A method as claimed in claim 5 wherein the coating comprising a metallic bond coating and a ceramic coating.

24. A method as claimed in claim 23 wherein the metallic bond coating is selected from the group comprising a MCrAlY coating, a MCrAl coating, a MCr coating, an aluminide coating, a platinum aluminide coating, a diffused platinum coating and a diffused chromium coating.

25. A method as claimed in claim 23 wherein the ceramic coating is selected from the group comprising zirconia and magnesia-alumina spinel.

26. A method as claimed in claim 5 comprising applying the coating by a method from the group comprising plasma spraying, air plasma spraying, vacuum plasma spraying, physical vapour deposition, chemical vapour deposition and plating and diffusion heat treatment.

27. A method as claimed in claim 2 comprising removing material from the surface of at least one aerofoil and adding material to the surface of the at least one aerofoil on the structure.