Patent ID: 8092146

Claim:
An aircraft turbofan gas turbine engine comprising: an annular outer case surrounding a fan assembly; an annular core case positioned within the outer case and accommodating a compressor assembly, a combustion gas generator assembly and a turbine assembly, the annular outer and core cases defining an annular bypass air duct therebetween for directing a bypass air flow driven by the fan assembly to pass therethrough; a core compartment configured within the annular core case, the core compartment having an inlet defined in the annular core case for introducing a first portion of the bypass air flow into the core compartment to cool a number of engine components located within the core compartment and having an outlet defined in the annular core case downstream of the inlet, the core compartment being sealed to allow the first portion of the bypass air flow to be discharged only through the outlet and back to the annular bypass air duct; and an active tip clearance control (ATCC) apparatus located within the sealed core compartment, the ATCC apparatus having an inlet defined in the annular core case for introducing a second portion of the bypass air flow into the ATCC apparatus and having a vent passage in fluid communication with atmosphere, the ATCC apparatus being sealed to impede the second portion of the bypass air flow from mixing with the first portion of the bypass air flow.