A gas turbine engine is disclosed which includes a bypass passage that in some embodiments are capable of being configured to act as a resonance space. The resonance space can be used to attenuate/accentuate/etc a noise produced elsewhere. The bypass passage can be configured in a number of ways to form the resonance space. For example, the space can have any variety of geometries, configurations, etc. In one non-limiting form the resonance space can attenuate a noise forward of the bypass duct. In another non-limiting form the resonance space can attenuate a noise aft of the bypass duct. Any number of variations is possible.

An axial flow turbomachine (102) for producing thrust to propel an aircraft is shown. The turbomachine has an inner duct (202) and an outer duct (204), both of which are annular and concentric with one another. An inner fan (206) is located in the inner duct, and is configured to produce a primary pressurised flow (P). An outer fan (207) is located in an outer duct, and is configured to produce a secondary pressurised flow (S). The outer fan has a hollow hub (208) through which the inner duct passes. A hub-tip ratio of the outer fan is from 1.6 to 2.2 times a hub-tip ratio of the inner fan.

An axial flow turbomachine (102) for producing thrust to propel an aircraft is shown. The turbomachine has an inner duct (202) and an outer duct (204), both of which are annular and concentric with one another. An inner fan (206) is located in the inner duct, and is configured to produce a primary pressurised flow (P). An outer fan (207) is located in an outer duct, and is configured to produce a secondary pressurised flow (S). The outer fan has a hollow hub (208) through which the inner duct passes. A hub-tip ratio of the outer fan is from 1.6 to 2.2 times a hub-tip ratio of the inner fan.

An ultra-efficient “green” aircraft propulsor utilizing an augmentor fan is disclosed. A balanced design is provided combining a fuel efficient and low-noise high bypass ratio augmentor fan and a low-noise shrouded high bypass ratio turbofan. Three mass flow streams are utilized to reduce propulsor specific fuel consumption and increase performance relative to conventional turbofans. Methods are provided for optimization of fuel efficiency, power, and noise by varying mass flow ratios of the three mass flow streams. Methods are also provided for integration of external propellers into turbofan machinery.

An ultra-efficient “green” aircraft propulsor utilizing an augmentor fan is disclosed. A balanced design is provided combining a fuel efficient and low-noise high bypass ratio augmentor fan and a low-noise shrouded high bypass ratio turbofan. Three mass flow streams are utilized to reduce propulsor specific fuel consumption and increase performance relative to conventional turbofans. Methods are provided for optimization of fuel efficiency, power, and noise by varying mass flow ratios of the three mass flow streams. Methods are also provided for integration of external propellers into turbofan machinery.

A triple-flow turbomachine for an aircraft, including a power transmission module including a torque input connected to a turbine shaft, a first torque output of a gearbox connected to a main shaft for rotatably driving a main fan propeller, and a second torque output of a planet gear connected to a secondary shaft for rotatably driving a secondary fan propeller. The planet gear is independent of the gearbox and arranged downstream of the gearbox.

A triple-flow turbomachine for an aircraft, including a power transmission module including a torque input connected to a turbine shaft, a first torque output of a gearbox connected to a main shaft for rotatably driving a main fan propeller, and a second torque output of a planet gear connected to a secondary shaft for rotatably driving a secondary fan propeller. The planet gear is independent of the gearbox and arranged downstream of the gearbox.

A gas turbine engine has an engine core including a primary flowpath. A first bypass duct is positioned radially outward of the engine core. A gas discharge protrudes radially into the first bypass duct. The gas discharge includes a fairing defining a lobed outlet. The lobed outlet includes a plurality of axially aligned peaks and axially aligned valleys. Each of the axially aligned valleys is configured to prevent a fluid passing through the valley from traveling radially inward immediately downstream of the fairing creating regions of relatively cool, mixed, and hot airflows.

A gas turbine engine has an engine core including a primary flowpath. A first bypass duct is positioned radially outward of the engine core. A gas discharge protrudes radially into the first bypass duct. The gas discharge includes a fairing defining a lobed outlet. The lobed outlet includes a plurality of axially aligned peaks and axially aligned valleys. Each of the axially aligned valleys is configured to prevent a fluid passing through the valley from traveling radially inward immediately downstream of the fairing creating regions of relatively cool, mixed, and hot airflows.

A section for a gas turbine engine according to an example of the present disclosure includes, among other things, a rotor including a row of blades extending in a radial direction outwardly from a hub. The row of blades deliver flow to a bypass flow path, an intermediate flow path, and a core flow path. A first case surrounds the row of blades to establish the bypass flow path. A first flow splitter divides flow between the bypass flow path and a second duct. A row of guide vanes extends in the radial direction across the bypass flow path. A second flow splitter radially inboard of the first flow splitter divides flow from the second duct between the intermediate flow path and the core flow path. A bypass port interconnects the intermediate and bypass flow paths. A method of operation for a gas turbine engine is also disclosed.