Patent ID: 8910465

Claim:
A gas turbine engine, comprising: an engine core; a first fan operable to generate a first air stream at a first pressure downstream thereof; a second fan positioned downstream of the first fan, the second fan operable to receive a portion of the first air stream and generate a second air steam at a second pressure; a fan bypass duct operative to direct a portion of the second air stream to a bypass stream around the engine core; an other fan bypass duct operative to direct a portion of the first air stream to an other bypass stream around the engine core; and an adaptive heat exchange system operative to cool an object of cooling using the air from the fan bypass duct and/or the other fan bypass duct as a cooling medium; wherein the gas turbine engine is configured to operate in a first mode in which the second pressure in the fan bypass duct is greater than the first pressure in the other fan bypass duct, and in a second mode in which the second pressure in the fan bypass duct is substantially the same as the first pressure in the other fan bypass duct; and wherein in the first mode the adaptive heat exchange system routes cooling medium from the fan bypass duct to the other fan bypass duct, and in the second mode the adaptive heat exchange system routes cooling medium from the other fan bypass duct to the other fan bypass duct.