摘要 |
<p>A tip clearance control system operated by differential air pressure has a movable shroud liner segment assembly (24) which forms the inner circumference of an annular pressure chamber (50) encircling the blades (22) of a rotary stage. High pressure air is bled into the chamber (50) from a source of HP compressor delivery air through small holes (41). The chamber (50) may be vented rapidly through an electrically controlled (86,84,82) valve (80) into the engine bypass duct. When the valve is opened pressure in the chamber (50) is dropped quickly below gas path pressure (PD) to move the shroud liner segments (24) radially outwards thereby increasing blade tip clearance.</p> |