Patent ID: 7946808

Claim:
A rotor and a stator assembly, the rotor comprising at least one stage of rotor blades and the stator comprising at least one stage of stator vanes, the rotor blades having aerofoils and platforms, the rotor blade platforms being arranged at the radially inner ends of the rotor blade aerofoils, the stator vanes having aerofoils and platforms, the stator vane platforms being arranged at the radially inner ends of the stator vane aerofoils, wherein a seal having a clearance is defined between the rotor blade platforms and the stator vane platforms, and wherein a portion of the rotor blade platforms and/or a portion of the stator vane platforms are arranged such that below a predetermined temperature the portion of the rotor blade platforms and/or a portion of the stator vane platforms have an original position to decrease the clearance of the seal and such that above the predetermined temperature the portion of the rotor blade platforms and/or the portion of the stator vane platforms changes shape to increase the clearance of the seal, and such that when the temperature moves from above the predetermined temperature to below the predetermined temperature the portion of the rotor blade platforms and/or the portions of the stator vane platforms change shape to decrease the clearance of the seal, the portion of the rotor blade platforms and/or the portion of the stator vane platforms being arranged at the downstream end of the rotor blade platforms and/or at the downstream end of the stator vane platforms, and wherein the portion of the rotor blade platforms and/or the portion of the stator vane platforms comprises a bimetallic member.