Patent ID: 6126390
Filing Date: 2000-10-03
Classification: F01D

Abstract:
Passive clearance control system in the turbine section of a gas turbine including a turbine casing in which, in addition to nozzle vanes, rotor blades are provided, said rotor blades being arranged on a rotor and preferably having a shroud, tips of said shroud being surrounded by stator shroud segments suspended in the turbine casing and forming a clearance with a width which is controlled by a heating-cooling channel system, said heating-cooling channel system being supplied with air from an air stream from a compressor section of the gas turbine and bypassing a combustion chamber of the gas turbine, said air stream reaching an annulus, which is bounded by a stator ring, via a plurality of metering holes, said passive clearance control system comprising:a ring-shaped orifice plate interacting with the metering holes, said orifice plate closing said metering holes to varying degrees as a function of the temperature of the air stream reaching said metering holes,wherein a fraction of hot gas flowing across the nozzle vanes and the rotor blades is allowed to reach an aft portion of the annulus, when viewed in a direction of flow through the gas turbine, via a clearance between the stator ring and the stator shroud segments in a low-load turbine operation.