Abstract: A turbomachine for an aircraft is provided. The turbomachine includes a plurality of radially-extending blades and an annular endwall opposite the radially-extending blades. The endwall includes an endwall treatment recessed into the endwall. The endwall treatment is characterized by a casing treatment volume compressibility factor (CTVCF), and a casing treatment normalized volume (CTNV), and a blade tip Mach number (Mtip).

Abstract: A turbomachine for an aircraft is provided. The turbomachine includes a plurality of radially-extending blades and an annular endwall opposite the radially-extending blades. The endwall includes an endwall treatment recessed into the endwall. The endwall treatment is characterized by a casing treatment volume compressibility factor (CTVCF), and a casing treatment normalized volume (CTNV), and a blade tip Mach number (Mtip).

Abstract: An inlet duct for a nacelle of a ducted fan engine includes an inlet portion at an upstream end of the inlet duct, an acoustic liner arranged downstream of the inlet portion, and a fan section arranged downstream of the acoustic liner. The inlet portion and the acoustic liner are coupled together at an inlet-acoustic liner interface extending circumferentially about the inner surface of the inlet duct, and the acoustic liner and the fan section are coupled together at a fan section hardwall-acoustic liner interface extending circumferentially about the inner surface of the inlet duct. At least one of the acoustic liner, the inlet-acoustic liner interface, and the fan section hardwall-acoustic liner interface having a structure that circumferentially alters a magnitude and a phase of an acoustic wave reflection of the inlet duct to attenuate flutter bite of a fan.

Abstract: Variable bleed valves with struts for aerodynamic stability are described. An apparatus described herein includes a variable bleed valve port, and a strut disposed within the variable bleed valve port, the strut defining a plane and a plurality of holes disposed perpendicularly to the plane, the plurality of holes disposed in a pattern to dampen an acoustic response associated with the variable bleed valve port.

Abstract: Methods, apparatus, systems, and articles of manufacture are disclosed to implement an integrated stator-fan frame assembly. An integrated fan exit stator-fan frame strut assembly for a gas turbine engine includes a fan exit stator portion having an airfoil including a leading edge and a trailing edge, and a fan frame strut portion including a leading edge and a trailing edge, the leading edge of the fan frame strut portion aerodynamically integrated with the trailing edge of the fan exit stator portion.

Abstract: A turbomachine includes an annular casing and a fan disposed inside the annular casing and mounted for rotation about an axial centerline. The fan includes fan blades that extend radially outwardly toward the annular casing. The fan has an average chord fan width according to a first performance factor. The fan has a quantity of fan blades according to a second performance factor.

Abstract: Methods, apparatus, systems, and articles of manufacture are disclosed to implement a low radius ratio fan blade for a gas turbine engine. A fan blade for a gas turbine engine includes an airfoil including a leading edge and a trailing edge extending between a root and a tip of the airfoil, a distance between the leading edge and the trailing edge defining a flow path length, a leading edge hub point defined by a radially innermost point of the leading edge, and an axial dovetail including a pair of opposed pressure faces, an axial length of the axial dovetail less than the flow path length, a top edge of the axial dovetail separating the pressure faces from the airfoil, the top edge of the axial dovetail radially outward of the leading edge hub point.

Abstract: Aero-acoustically damped bleed valves are disclosed. An example variable bleed valve apparatus comprises a variable bleed valve door to actuate the variable bleed valve apparatus, and a variable bleed valve port including an upstream edge and a downstream edge, the VBV port to define a secondary flowpath, the VBV door to cover the VBV port in a closed position, and a vortex device at the upstream edge of the variable bleed valve port, the vortex device including a vorticity generating feature along the upstream edge of the variable bleed valve port.

Abstract: An unducted single fan engine includes a housing having one or more fan blades coupled to the housing and configured to rotate circumferentially. The engine has one or more outlet guide vanes coupled to the housing. Each of the one or more guide vanes has a leading edge portion having a variable leading edge. The engine has one or more actuation devices coupled to each of the one or more outlet guide vanes. The one or more actuation devices are configured to control the variable leading edge of the respective outlet guide vane. The variable leading edge is controllable to vary the pitch, camber, lean angle, or sweep of the respective outlet guide vane.

Abstract: Variable bleed valves with inner wall controlled-flow circuits are disclosed. An example apparatus disclosed herein includes a casing segment defining a first flow path, a variable bleed valve port defining a second flow path, and a channel formed in the casing segment, the channel including a first opening into the first flow path, and a second opening into the second flow path, the channel defining a third flow path between the first opening and the second opening.

Abstract: Aero-acoustically damped bleed valves are disclosed. An example variable bleed valve apparatus comprises a variable bleed valve door to actuate the variable bleed valve apparatus, and a variable bleed valve port including an upstream edge and a downstream edge, the VBV port to define a secondary flowpath, the VBV door to cover the VBV port in a closed position, and a vortex device at the upstream edge of the variable bleed valve port, the vortex device including a vorticity generating feature along the upstream edge of the variable bleed valve port.

Abstract: Aero-acoustically damped bleed valves are disclosed. An example variable bleed valve apparatus comprises a variable bleed valve door to actuate the variable bleed valve apparatus, and a variable bleed valve port including an upstream edge and a downstream edge, the VBV port to define a secondary flowpath, the VBV door to cover the VBV port in a closed position, and a vortex device at the upstream edge of the variable bleed valve port, the vortex device including a vorticity generating feature along the upstream edge of the variable bleed valve port.

Abstract: An unducted single fan engine includes a housing having one or more fan blades coupled to the housing and configured to rotate circumferentially. The engine has one or more outlet guide vanes coupled to the housing. Each of the one or more guide vanes has a leading edge portion having a variable leading edge. The engine has one or more actuation devices coupled to each of the one or more outlet guide vanes. The one or more actuation devices are configured to control the variable leading edge of the respective outlet guide vane. The variable leading edge is controllable to vary the pitch, camber, lean angle, or sweep of the respective outlet guide vane.

Abstract: Methods, apparatus, systems, and articles of manufacture are disclosed for a variable bleed valve assembly. An example variable bleed valve assembly includes a variable bleed valve (VBV) door corresponding to a bleed port, an intermediary device operatively coupled to the VBV door, and a first actuator operatively coupled to the intermediary device, the first actuator to move between a first position and a second position, the first actuator to cause the intermediary device to move between the first position and the second position to cause the VBV door to move between the first position and the second position.

Abstract: Methods, apparatus, systems, and articles of manufacture are disclosed to implement an integrated stator-fan frame assembly. An integrated fan exit stator-fan frame strut assembly for a gas turbine engine includes a fan exit stator portion having an airfoil including a leading edge and a trailing edge, and a fan frame strut portion including a leading edge and a trailing edge, the leading edge of the fan frame strut portion aerodynamically integrated with the trailing edge of the fan exit stator portion.

Abstract: A turbomachine includes an annular casing and a fan disposed inside the annular casing and mounted for rotation about an axial centerline. The fan includes fan blades that extend radially outwardly toward the annular casing. The fan has an average chord fan width according to a first performance factor. The fan has a quantity of fan blades according to a second performance factor.

Abstract: Methods, apparatus, systems, and articles of manufacture are disclosed to implement a low radius ratio fan blade for a gas turbine engine. A fan blade for a gas turbine engine includes an airfoil including a leading edge and a trailing edge extending between a root and a tip of the airfoil, a distance between the leading edge and the trailing edge defining a flow path length, a leading edge hub point defined by a radially innermost point of the leading edge, and an axial dovetail including a pair of opposed pressure faces, an axial length of the axial dovetail less than the flow path length, a top edge of the axial dovetail separating the pressure faces from the airfoil, the top edge of the axial dovetail radially outward of the leading edge hub point.