Rolls-royce Corporation

Alstom Technology Limited

Neil William Harvey

Stephane Michel Marcel Baralon

Mark Richard Stokes

David Andrew Bagshaw

Martin George Rose

A shroudless blade for use in a compressor or fan of an axial flow gas turbine engine includes a treatment to the tips of the blades to improve the surge margin of the compressor. A series of cross bleed holes are formed at the tip of the blade, which may be a stator or rotor component, extending between the pressure and suction sides of the blades. Notches are provided at the tip of the blades to provide initiation sites for any fatigue cracks such that the cracks propagate from the base of these slots or notches and radially inwards into the body of the blades. The present invention provides an arrangement, which by provision of the cross bleed holes the propagation of the cracks is arrested. A preferred placement and orientation for the holes for best mechanical and aerodynamic performance is described.

Shroudless blade

A circumferential row of aerofoil members span an annular duct for carrying a flow of compressible fluid. The duct is centered on the axis of a turbomachine. Pressure and suction surfaces of neighboring aerofoil members bound respective sectoral passages which receive the flow of compressible fluid. The row of aerofoil members includes at least one radial endwall to which the tangent to the trailing edge of each aerofoil member at midspan is substantially orthogonal. Each aerofoil member has reverse compound lean. Each aerofoil member further has a leading edge which has a position at the endwall which is upstream of its position at midspan. The endwall at each sectoral passage has a non-axisymmetrical cross-section formed by a region that, in meridional section, is convexly profiled immediately adjacent the pressure surface and a region that, in meridional section, is concavely profiled immediately adjacent the suction surface.

Aerofoil members for a turbomachine

A turbine bladefor a gas turbine enginehaving an axis, the turbine bladecomprising: an aerofoilincluding a high pressure surface, a low pressure surface, a root portionand a tip surfaceextending transverse from the high and low pressure surfacesand, the high and low pressure surfacesandcurve from the root portionto the tip surfacein a direction that is substantially tangential to the axisof the engine; and an air leakage restricting memberon the tip surface, the air leakage restricting memberbeing configured to substantially prevent leakage of air over the tip surface

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Derby, United Kingdom

Neil William Harvey