Patent ID: 6925814
Filing Date: 2005-08-09
Classification: F01D

Abstract:
1. A gas turbine engine having a plurality of turbine rotor blades and a turbine shroud assembly, the turbine shroud assembly including a plurality of turbine shroud segments radially spaced apart from the plurality of turbine rotor blades, the gas turbine engine further comprising: an annular shroud housing adapted to be secured within a turbine support casing; turbine shroud segment attachment members mounted to an inner side of the annular shroud housing and adapted to support the turbine shroud segments in place; a first cooling air passage adapted to direct a first cooling air flow from a compressor portion of the gas turbine engine to at least one gas turbine engine component downstream of the shroud housing relative to a combustion gas path through the gas turbine engine; a second cooling air passage branching from the first cooling air passage and adapted to direct a second cooling air flow from the first cooling passage to the shroud housing to cool the shroud housing and thereby affect the tip clearance between the turbine shroud segments and the turbine rotor blades; a flow control member associated with the second cooling air passage and adapted to selectively control a cooling air flow passing through the second cooling air passage, the flow control member cooling air being selectively positionable between a first position, in which a first cooling air flow rate is permitted to pass through the second cooling air passage, and a second position, in which a second cooling air flow rate is permitted to pass through the second cooling air passage; and a third cooling air passage isolated from the second air passage, adapted to direct a third cooling air flow both for cooling the turbine shroud segment attachment members and the turbine shroud segments and for creating an air seal around the turbine shroud segments in order to prevent combustion gas leakage.