Auxiliary propulsor for a variable cycle gas turbine engine

A variable cycle gas turbine engine comprising:

• a core engine comprising:
• a low pressure spool for generating a stream of bypass air and a stream of pressurized air;
• a high pressure spool for further pressurizing the stream of pressurized air to generate a stream of combustion air and a stream of supercharged auxiliary air;
• and
• an engine case surrounding the low pressure spool and the high pressure spool, the engine case having a first inlet for receiving a first stream of inlet air and a first outlet for discharging the combustion air and the stream of bypass air from the variable cycle gas turbine engine;
• a peripheral case surrounding the engine case to form a peripheral duct having a second inlet for receiving a second stream of inlet air and a second outlet separate from first outlet for discharging the second stream of inlet air from the variable cycle gas turbine engine;
• an auxiliary combustor positioned within the peripheral duct;
• an auxiliary propulsor surrounding the engine case downstream of the auxiliary combustor within the peripheral case and configured to discharge air into the second outlet;
• a bleed duct extending from the high pressure spool to an inlet of the auxiliary combustor;
• and
• variable ductwork to alternatively direct airflow through the engine in a first mode and a second mode;
• wherein the first mode comprises directing the supercharged auxiliary air to the auxiliary combustor through the bleed duct, and directing inlet air through the peripheral duct;
• and
• wherein the second mode comprises directing the supercharged auxiliary air into the stream of bypass air of the core engine and preventing inlet air from entering the peripheral duct;
• a bypass duct positioned within the engine case to direct the bypass air out of the gas turbine engine;
• and
• an exhaust duct disposed within the engine casing to discharge the combustion air from the engine case separate from the stream of bypass air, wherein the bleed duct extends through the bypass duct to connect directly with the auxiliary combustor.

A variable cycle gas turbine engine comprising:

• a core engine configured as a low bypass ratio turbofan and comprising:
• a low pressure spool;
• a high pressure spool;
• and
• a bypass duct;
• a peripheral duct comprising:
• an annular passageway surrounding the bypass duct;
• and
• an inlet door for controlling airflow through the annular passageway;
• an auxiliary propulsor comprising:
• a peripheral combustor positioned within the peripheral duct;
• and
• an auxiliary propulsor comprising:
• a turbine blade portion positioned to receive exhaust gas from the peripheral combustor;
• and
• a turbofan blade portion extending from the turbine blade portion and configured to accelerate air in the annular passageway;
• and
• a bleed duct comprising:
• a passageway extending from the high pressure spool;
• and
• an adjustable discharge portion configured to alternately extend to the bypass duct to increase the pressure ratio across the low pressure spool, or the peripheral duct to increase the bypass ratio of the core engine and sustain a combustion process in the peripheral combustor;
• wherein exhaust gas of the auxiliary propulsor in the peripheral duct is discharged from the variable cycle gas turbine engine separately from exhaust gas of the high pressure spool in the core engine;
• wherein the bleed duct extends through the bypass duct to connect directly with the peripheral combustor.