Abstract: A turbine nozzle includes first and second vanes joined to outer and inner bands. The vanes include outboard sides defining outboard flow passages containing axial splitlines, and opposite inboard sides defining an inboard flow passage without axial splitline. The two vanes include different cooling circuits for differently cooling the inboard and outboard vane sides.

Abstract: A method of assembling a gas turbine assembly includes providing a core gas turbine engine including a high-pressure compressor, a combustor, and a turbine, coupling a low-pressure turbine to the core gas turbine engine, coupling a booster compressor to a gearbox, and coupling the gearbox to the low-pressure turbine such that the booster compressor is driven by the low-pressure turbine.

Abstract: A turbine engine assembly includes, a core gas turbine engine, a first low-pressure turbine section in serial flow communication with the core gas turbine engine, the first low-pressure turbine section configured to rotate in a first rotational direction, a first gear assembly coupled to the first low-pressure turbine section, a second low-pressure turbine section coupled to the gear assembly, the second low-pressure turbine section configured to rotate in a second rotational direction, and a fan assembly coupled to the second low-pressure turbine section.

Abstract: A method for assembling a gas turbine engine includes coupling a gearbox to a low-pressure turbine, the gearbox includes a plurality of planetary gears intermeshed with the sun gear, each of the planetary gears includes a first gear portion having a first diameter and a second gear portion having a second diameter that is different than the first diameter.

Abstract: A gas turbine engine includes a compressor, combustor, and high pressure turbine operatively joined together. The turbine includes a row of nozzle vanes followed by a row of rotor blades. The vanes and blades have corresponding forward and aft internal cooling channels. First, second, third, and fourth bleed circuits are joined in flow communication with different stages of the compressor for bleeding pressurized air therefrom at different pressures to provide coolant to the forward and aft channels of the turbine vanes and blades.

Abstract: A gas turbine engine combustion system includes a plurality of fuel injectors circumferentially disposed around a combustor in a one to one fuel supply relationship with a plurality of fuel nozzle valves, and an electronic controller for controlling the fuel nozzle valves to eliminate and/or reduce hot streaking in response to sensed hot streak conditions. The fuel nozzle valves may be modulating valves. The electronic controller may be used to individually control the fuel nozzle valves. The hot streak conditions may be sensed with temperature sensors such as temperature sensors operably mounted in the combustor. A program in the electronic controller may be used for determining broken or malfunctioning sensors by calculating a combustor temperature and comparing it to measured temperatures from the sensors and comparing the measured fuel pressures in the individual fuel nozzle circuits with the simulated or calculated fuel pressures.

Abstract: A method for assembling a gas turbine engine includes coupling a low-pressure turbine to a core turbine engine, and coupling a counter-rotating fan assembly including a first fan assembly and a second fan assembly to the low-pressure turbine such that the first fan assembly rotates in a first direction and the second fan assembly rotates in an opposite second direction.

Abstract: A method for assembling a gas turbine engine includes providing a core gas turbine engine including a high-pressure compressor, a combustor, and a turbine, and coupling a counter-rotating fan assembly to the core gas turbine engine such that air discharged from the counter-rotating fan assembly is channeled directly into an inlet of the gas turbine engine compressor.

Abstract: A turbofan engine assembly is provided. The turbofan engine assembly includes a core gas turbine engine, a core cowl which circumscribes the core gas turbine engine, a nacelle positioned radially outward from the core cowl, a fan nozzle duct defined between the core cowl and the nacelle, and an inner core cowl baffle assembly positioned within the fan nozzle duct. The inner core cowl baffle assembly includes a first core cowl baffle coupled to a portion of the core cowl within the fan nozzle duct, a second core cowl baffle coupled to a portion of the core cowl and positioned a distance radially inward from the first core cowl baffle, and an actuator assembly configured to vary the throat area of the fan nozzle duct by selectively repositioning the second core cowl baffle with respect to the first core cowl baffle. A method for operating the turbofan engine assembly is also provided.

Abstract: A method for operating a turbofan engine assembly is provided. The turbofan engine assembly includes a core cowl which circumscribes the core gas turbine engine, a nacelle positioned radially outward from the core cowl, a fan nozzle duct having an area defined between the core cowl and a portion of the nacelle, a first cowl and a second cowl that define a portion of the nacelle wherein the second cowl is repositionable with respect to the first cowl, and a thrust reverser assembly wherein the second cowl surrounds the thrust reverser assembly. The method includes varying an operating speed of the fan assembly from a first operating speed to a second operating speed. The method further includes selectively positioning the second cowl between a first operational position and a second operational position to vary the area of the fan nozzle duct to facilitate improving engine efficiency at the second operating speed.

Abstract: A duplex turbine nozzle includes a row of different first and second vanes alternating circumferentially between radially outer and inner bands in vane doublets having axial splitlines therebetween. The vanes have opposite pressure and suction sides spaced apart in each doublet to define an inboard flow passage therebetween, and corresponding outboard flow passages between doublets. The vanes have different patterns of film cooling holes with larger cooling flow density along the outboard passages than along the inboard passages.

Abstract: A method for assembling a gas turbine engine assembly includes coupling a fan assembly to a core gas turbine engine such that the fan assembly is upstream from the core gas turbine engine, coupling a low-pressure turbine downstream from the core gas turbine engine such, wherein the low-pressure turbine includes a disk and a plurality of splines formed in the disk, providing a shaft that includes a first end and a second end that includes a plurality of splines, coupling the shaft first end to the fan assembly, and coupling the shaft second end to the low-pressure turbine such that the shaft splines mesh with the disk splines such that torque is transmitted from the low-pressure turbine to the fan assembly via the shaft during engine operation.

Abstract: A method for assembling a gas turbine engine includes coupling a low-pressure turbine to a core turbine engine, coupling a gearbox to the low-pressure turbine, coupling a first fan assembly to the gearbox such that the first fan assembly rotates in a first direction, and coupling a mechanical fuse between the first fan assembly and the low-pressure turbine such that the mechanical fuse fails at a predetermined moment load.

Abstract: A turbofan engine includes a fan, compressor, combustor, high pressure turbine, and low pressure turbine joined in serial flow communication. The high pressure turbine includes two stages of rotor blades to effect corresponding exit swirl in the combustion gases discharged therefrom. A transition duct includes fairings extending between platforms for channeling the combustion gases to the low pressure turbine with corresponding swirl. First stage rotor blades in the low pressure turbine are oriented oppositely to the rotor blades in the high pressure turbine for counterrotation.

Abstract: A gas turbine engine shroud includes a row of different first and second shroud segments alternating circumferentially therearound. The first segments have a first pattern of first cooling holes extending therethrough. The second segments have a second pattern of second cooling holes extending therethrough. The corresponding patterns have different collective flowrate capabilities.

Abstract: A method for assembling a gas turbine engine includes coupling a low-pressure turbine to a core turbine engine, coupling a gearbox including an input, a first output, and a second output, to the low-pressure turbine, coupling a first fan assembly to the gearbox first output, and coupling a second fan assembly to the gearbox second output.

Abstract: A turbofan engine includes a fan, compressor, combustor, single-stage high pressure turbine, and low pressure turbine joined in serial flow communication. First stage rotor blades in the low pressure turbine are oriented oppositely to the rotor blades in the high pressure turbine for counterrotation. First stage stator vanes in the low pressure turbine have camber and twist for carrying swirl directly between the rotor blades of the high and low pressure turbines.

Abstract: A method for assembling a gas turbine engine includes coupling a low-pressure turbine to a core turbine engine, coupling a counter-rotating fan assembly including a forward fan assembly and an axially aft fan assembly to the low-pressure turbine such that the forward fan assembly rotates in a first direction and the aft fan assembly rotates in an opposite second direction, and coupling a booster compressor to the low-pressure turbine such that the booster compressor rotates in the first direction.

Abstract: A turbine nozzle includes a row of vanes joined to radially outwardly inclined outer and inner bands. Each vane has camber and an acute twist angle for importing swirl in combustion gases discharged at trailing edges thereof. The trailing edges are tilted forwardly from the inner band to the outer band for increasing aerodynamic efficiency.

Abstract: A power take-off system for a gas turbine engine includes a starter coupled to a second spool, and a clutch assembly coupled between the starter and a first spool, the clutch assembly configured to couple the first spool to the starter when starting the gas turbine engine assembly. A method of assembling a gas turbine engine assembly that includes the power take-off system, and a gas turbine engine assembly including the power take-off system are also described.