Architecture for an axially compact, high performance propulsion system
A reverse-core turbofan engine including a propulsor section including a fan and a fan-tip turbine configured to deliver air to a core duct, including a first portion, disposed aft of the propulsor section, and direct air aft, toward an inlet of a reverse-core gas generator, and a second portion, configured to receive air from an exit of the gas generator and direct the air forward and radially outward of the propulsor, toward the fan-tip turbine in the propulsor, thereby driving the propulsor.
1. A reverse-core turbofan engine comprising:
a propulsor section including a fan and a fan-tip turbine, the propulsor section directing air toward a bypass splitter to divide the air into a first airstream and a second airstream;
a reverse-core gas generator including a compressor section, a combustor section, and a high pressure turbine section, and
a core duct including:
a first portion, disposed aft of the propulsor section, configured to receive the first airstream from the propulsor section, and direct air aft, toward an inlet of the reverse-core gas generator;
a second portion, configured to receive air from an exit of the reverse-core gas generator and direct the air forward and radially outward of the propulsor section, toward the fan-tip turbine in the propulsor section, thereby driving the propulsor section;
at least one hollow strut disposed within the core duct and positioned between the high pressure turbine section and the fan-tip turbine, the at least one hollow strut being an exit guide vane for the second airstream;
a lobe mixer operably coupled to an exit of the core duct;
a heat exchanger operatively coupled to the core duct, the core duct operatively coupled to the compressor section, the heat exchanger located axially aft of, and radially inwardly of, the lobe mixer; and
a generator device operably coupled to the compressor section, the generator device directly mounted to a rotor shaft.
2. The reverse-core turbofan engine of claim 1 , wherein the core duct further includes a third portion, configured to receive air from an exit in the fan-tip turbine and direct the air aft, toward the exit of the core duct.
3. The reverse-core turbofan engine of claim 2 , further comprising a bypass duct radially exterior to an inlet of the core duct, and radially interior to the third portion of the core duct.
4. The reverse-core turbofan engine of claim 1 , wherein the at least one hollow strut is laterally disposed within the core duct.
5. The reverse-core turbine engine of claim 1 , wherein the fan-tip turbine includes a first fan-turbine rotor and a second fan-turbine rotor.
6. The reverse-core turbine engine of claim 5 , wherein the first fan-tip turbine rotor is configured to rotate in an opposite direction from the second fan-tip turbine rotor.
7. The reverse-core turbofan engine of claim 1 , wherein the fan-tip turbine is fluidly coupled to the compressor section.