| 摘要 |
A passive clearance control system is provided in the turbine section of a gas turbine engine in which turbine casing nozzle vanes and rotor blades are provided. The rotor blades are arranged on a rotor and preferably fitted with a shroud. The tips of the blades or shroud are surrounded by shroud segments suspended in the turbine casing, and a clearance between the tips and the shroud segments is formed and has a width which is controlled by a heating-cooling channel system. The channel system is supplied with a stream of air from the compressor section of the gas turbine and bypasses the combustion chamber to reach, via a plurality of metering holes, an annulus bounded by a stator ring. In a preferred aspect of the present invention, a ring-shaped orifice plate interacting with the metering holes is provided within the annulus which closes these metering holes to a varying degree depending on the temperature of the air stream reaching the heating-cooling channel system. A fraction of the hot gas flowing across the nozzle vanes and rotor blades is allowed to reach the annulus via a clearance between the stator ring and the stator shroud segments at least at a low turbine load.
|
