Shrouded aerofoils
AssigneeROLLS-ROYCE plc
InventorNeil M. Evans
Life of this patent
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Abstract
A shrouded aerofoil assembly such as a turbine rotor for a gas turbine engine has a multiplicity of blades with tip shrouds circumferentially distributed around a rotor disk. Inevitably, in use, the assembly vibrates and must be designed so the potentially most dangerous vibratory modes occur outside the engine speed range. The proposed arrangement has a number of neighbouring blades sharing a common shroud segment. Adjacent shroud segments are interlocked by Z-notch abutments. Blade assemblies have sufficient pre-twist load to maintain frictional contact in the interlocks over the speed range to maintain damping constraints.
Claims8
A shrouded aerofoil rotor assembly comprising:
- an annular array of shrouded aerofoil segments each of which comprises at least two aerofoil blades which share a common radially outer circumferential shared shroud segment, the shared shroud segment having opposite ends in the circumferential direction which are formed with notches to interlockingly engage with notches formed in the correspondingly shaped ends of neighbouring shared shroud segments, each shared shroud segment comprising at least two shroud sections formed integrally with their respective aerofoil blades,
- a shroud section is formed with at least one edge in a circumferential direction which on assembly lie adjacent edges of neighbouring shroud sections, and
- a shared shroud segment is formed by welding together at least two adjacent shroud sections at said adjacent edges,
- wherein during assembly of the rotor, each shared shroud segment is pre-twisted to urge abutting interlock faces to positively engage and the pre-twist load is sufficient to maintain positive engagement of the abutting interlock faces over the whole rotor operating speed.
A shrouded aerofoil rotor assembly comprising:
- an annular array of shrouded aerofoil segments each of which comprises at least two aerofoil blades which share a common radially outer circumferential shared shroud segment, the shared shroud segment having opposite ends in the circumferential direction which are formed with notches to interlockingly engage with notches formed in the correspondingly shaped ends of neighbouring shared shroud segments, each shared shroud segment comprising a shroud section formed integrally with a plurality of aerofoil blades, and
- a shroud section is formed with at least one edge in a circumferential direction which on assembly lie adjacent edges of neighbouring shroud sections,
- wherein said adjacent edges to be joined by welding are formed straight, and the edges of adjacent shroud segments which upon assembly abut in a circumferential direction are formed with notched faces;
- and
- during assembly of the rotor, each shared shroud segment is pre-twisted to urge abutting interlock faces to positively engage and the pre-twist load is sufficient to maintain positive engagement of the abutting interlock faces over the whole rotor operating speed.
Dependencies are inferred from the claim text.