Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A turbine blade 29 for a gas turbine engine 10 having an axis 20, the turbine blade 29 comprising: an aerofoil 30 including a high pressure surface 36, a low pressure surface 34, a root portion 38 and a tip surface 40 extending transverse from the high and low pressure surfaces 36 and 34, the high and low pressure surfaces 36 and 34 curve from the root portion 38 to the tip surface 40 in a direction that is substantially tangential to the axis 20 of the engine 10; and an air leakage restricting member 32 on the tip surface 40, the air leakage restricting member 32 being configured to substantially prevent leakage of air over the tip surface 40.

Abstract: A circumferential row of aerofoil members span an annular duct for carrying a flow of compressible fluid. The duct is centred on the axis of a turbomachine. Pressure and suction surfaces of neighbouring aerofoil members bound respective sectoral passages which receive the flow of compressible fluid. The row comprises 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.