Patent ID: 7665964

Claim:
A turbine of a gas turbine engine comprising: a fluid inlet and a fluid outlet arranged to pass a main flow of fluid between the inlet and the outlet; a plurality of axially alternating annular arrays of rotatable aerofoil members and fixed aerofoil members disposed between the fluid inlet and fluid outlet and being mounted within an annular casing having an inner wall and an outer wall, wherein during operation the main flow passes through the rotatable aerofoil members and fixed aerofoil members; and a plurality of radially inwardly extending baffles provided on the inner wall of the casing, the baffles being positioned axially between a selected one of said annular arrays of rotatable aerofoil members and an adjacent annular array of fixed aerofoil members, wherein the selected one of said annular arrays of rotatable aerofoil members is positioned upstream of said adjacent array of fixed aerofoil members such that during operation the main flow exits the selected one of said annular arrays of rotatable aerofoil members and enters the adjacent annular array of fixed aerofoil members at a first angle and a tip leakage flow between the selected one of said annular arrays of rotatable aerofoil members and said inner wall enters the adjacent annular array of fixed aerofoil members at a second angle that is adjusted by the baffles, the baffles being sized to adjust the second angle of the tip leakage flow, and wherein the baffles being substantially flat in profile and being angled with respect a center line of the turbine such that a tangential momentum component of the tip leakage fluid flow is reduced or removed before the tip leakage fluid flow reaches the adjacent annular array of fixed aerofoil members.