초록 ▼

A tip clearance control system operated by differential air pressure has a movable shroud liner segment assembly which forms the inner circumference of an annular pressure chamber encircling the blades of a rotary stage. High pressure air is bled into the chamber from a source of HP compressor deliv

A tip clearance control system operated by differential air pressure has a movable shroud liner segment assembly which forms the inner circumference of an annular pressure chamber encircling the blades of a rotary stage. High pressure air is bled into the chamber from a source of HP compressor delivery air through small holes. The chamber may be vented rapidly through an electrically controlled valve into the engine bypass duct. When the valve is opened pressure in the chamber is dropped quickly below gas path pressure to move the shroud liner segments radially outwards thereby increasing blade tip clearance.

대표청구항 ▼

[ I claim:] [1.] A pressure actuated tip clearance control system for a shroud structure of a gas turbine engine rotary stage lying between upstream and downstream stator assemblies comprising an annular plenum chamber formed between a movable annular shroud liner arrangement on the inner circumfere

[ I claim:] [1.] A pressure actuated tip clearance control system for a shroud structure of a gas turbine engine rotary stage lying between upstream and downstream stator assemblies comprising an annular plenum chamber formed between a movable annular shroud liner arrangement on the inner circumference of the chamber and a generally cylindrical casing forming the radially outer side of the plenum chamber, a source of high pressure compressor delivery air at a pressure higher than pressure in the gas path, a plurality of apertures in an upstream wall of the chamber operative, in use, to continuously bleed fluid from the source of high pressure compressor delivery air into the plenum chamber in order to contract the movable shroud liner assembly, valve means for venting fluid from the plenum chamber to a region of pressure lower than the gas path pressure in order to expand the movable shroud liner assembly for increased tip clearance, a leakage path between a downstream side of the movable shroud liner arrangement and the downstream stator assembly, and further two-way valve means adapted to connect said leakage path with alternative sources of fluid to maintain continuous fluid flow in the leakage path, the alternate sources of fluid comprising the plenum chamber when it is charged with high pressure or a further pressure region when the plenum chamber is vented.