Cooled cooling air system for a turbofan engine
An exemplary gas turbine engine includes a fan bypass duct defined between a fan nacelle and core cowl of an engine core. The engine core includes a cooled cooling air system configured to receive cooling air from a primary flowpath bleed at a diffuser within the engine core and configured to provide cooled cooling air to at least one component within the engine core. The cooled cooling air system including an air-air heat exchanger.
1. A gas turbine engine comprising:
a fan bypass duct defined between a fan nacelle and core cowl of an engine core;
the engine core including a cooled cooling air system configured to receive cooling air from a primary flowpath bleed within the engine core and configured to provide cooled cooling air to at least one component within the engine core, the cooled cooling air system further including a cold air modulator having a first position, a second position, and at least one intermediate position between the first and second positions;
the cooled cooling air system including an air-air heat exchanger; and
a controller controllably connected to the cold air modulator and configured to control a position of said cold air modulator based on at least one of an engine power and a combination of engine rotor speed and ambient temperatureengine operating condition.
2. The gas turbine engine of claim 1 , wherein the heat exchanger is disposed within the engine core, a cold air duct connects a cold air inlet of the heat exchanger to said fan bypass duct, and a spent air duct connects a spent air outlet of the heat exchanger to an outlet port, and wherein at least one of the cold air duct, the spent air duct, and the air-air heat exchanger are structurally supported by at least one connection to the core cowl.
3. The gas turbine engine of claim 2 , wherein a high pressure side of the air-air heat exchanger is structurally supported by a connection to the core cowl.
4. The gas turbine engine of claim 1 , wherein the cold air modulator is configured to regulate a flow of cold air to the heat exchanger.
5. The gas turbine engine of claim 4 , wherein the modulator is a hinged scoop configured to increase a pressure of fan duct air at an inlet of a cold air duct.
6. The gas turbine engine of claim 5 , wherein the hinged scoop is flush with a radially outward surface of the core cowl in a closed position, and wherein the hinged scoop extends radially into the fan bypass duct in an open position.
7. The gas turbine engine of claim 5 , wherein the hinged scoop includes side walls having a radially aligned aspect.
8. The gas turbine engine of claim 4 , wherein the modulator is upstream of the heat exchanger.
9. The gas turbine engine of claim 4 , wherein the controller is configured to modulate the flow of cold air to the heat exchanger as a function of engine power.
10. The gas turbine engine of claim 4 , wherein the controller is configured to modulate the flow of cold air to the heat exchanger as a function of a rotor speed and an ambient temperature.
11. The gas turbine engine of claim 1 , wherein the cooled cooling air system includes a spent air exhaust outlet at a radially outward surface of the core cowl, the spent air exhaust outlet being downstream of a fan bypass duct nozzle.
12. The gas turbine engine of claim 1 , wherein the cooled cooling air system includes a spent air exhaust outlet at a radially outward surface of the core cowl, the spent air exhaust outlet being upstream of a fan bypass duct nozzle.
13. The gas turbine engine of claim 12 , further comprising a ramp feature protruding radially into said fan bypass duct upstream of said spent air exhaust outlet.
14. The gas turbine engine of claim 13 , wherein the ramp feature is moveable along a longitudinal axis defined by the engine core.
15. The gas turbine engine of claim 12 , wherein the ramp feature has a fixed axial position within the fan bypass duct, along an axis defined by the engine core.
16. The gas turbine engine of claim 1 , wherein the gas turbine engine is a geared turbofan engine.
17. The gas turbine engine of claim 1 , wherein the primary flowpath bleed is positioned at at least one of a diffuser, a combustor section and a compressor flowpath fore of an aft most stage of the compressor flowpath.
18. The gas turbine engine of claim 6 , wherein the controller is configured to modulate the magnitude by which said scoop extends radially into said fan bypass duct as a function of engine power.
19. The gas turbine engine of claim 6 , wherein the controller is configured to modulate the magnitude by which said scoop extends radially into said fan bypass duct as a function of an engine rotor speed and an ambient temperature.
20. The gas turbine engine of claim 1 , wherein said cooled cooling air system is mounted to the engine core circumferential position between 45 degrees and 135 degrees with an engine mounting pylon defining a 0 degree circumferential position.