Mechanical blade tip clearance control apparatus for a gas turbine engine

摘要

A gear-actuated mechanical clearance control apparatus is operable for controlling the clearance between rotor blade tips and the casing shroud of a gas turbine engine. The apparatus includes a pair of annular rings which extend about the casing shroud, a shroud hanger disposed between the casing and an opening in the casing and between the annular rings, and a shroud segment defining a circumferential portion of the casing shroud and disposed in the casing opening. The apparatus also has an actuating mechanism which includes driven gear sectors on the annular rings which face toward one another and a gear disposed between the annular rings and having a peripheral driving gear sector which intermeshes with the driven gear sectors of the annular rings. Upon rotation of the gear, the annular rings undergo opposite circumferential movement causing radial movement of the shroud hanger and the shroud segment therewith to establish the clearance between the shroud segment and rotor blade outer tips.