SYSTÈME PASSIF DE RÉGLAGE DU JEU D'EXTRÉMITÉ D'AUBE POUR UN MOTEUR DE TURBINE À GAZ

摘要

The present disclosure relates to a gas turbine engine (10) including a turbine wheel (24) mounted for rotation about a central reference axis (11) and a turbine shroud ring (26) mounted radially outward from the turbine wheel (24). The turbine wheel (24) includes a plurality of blades (30) that are spaced apart radially from the turbine shroud ring (26) to establish a blade tip clearance gap (36). The gas turbine engine (10) further includes a blade tip clearance control system (40) that passively controls the size of the blade tip clearance gap (36) based on engine operation, the clearance control system (40) comprising a shroud-ring support (34) coupled to the variable-diameter turbine shroud ring (26) that is configured to drive motion of the variable-diameter turbine shroud ring (26) radially inward or outward based on temperature of the shroud-ring support (34) and defining at least in part a cavity (50) located radially outward of the variable-diameter turbine shroud ring (26), wherein the cavity (50) is fluidly coupled to a bleed-air passageway (46) that extends from the compressor (14) to the cavity (50) without interruption from a valve and to a cooling-air passageway (47) that extends from the cavity (50) to the low-pressure section (22) such that pressurized bleed air from the compressor (14) is conducted to the cavity (50) of the passive blade tip clearance control system (40) so that the temperature and motion of the shroud-ring support (34) is controlled based on the operating conditions of the gas turbine engine (10) without active control of the pressurized bleed air provided to the cavity (50).