Abstract:
PROBLEM TO BE SOLVED: To shorten the low shaft of an engine while increasing the output density of the engine.SOLUTION: A gas turbine engine 20 includes a low shaft 40, a counter-rotating low-pressure compressor 60, and a counter-rotating low-pressure turbine 62. The counter-rotating low-pressure turbine 62 includes inside blade sets 120 which are connected to the low shaft 40 via a gear device 116, and an outside blade set 122 which is inserted between the inside blade sets 120. The outside blade set 122 is fixed to an outside rotor 126; a front end of the outside rotor 126 is supported on a central turbine frame 134 by a bearing 150; and a rear end of the outside rotor 126 is supported on the low shaft 40 by the bearing 152. In addition, the gear device 116 comprises a sun gear 140, a splitter gear 142 which is meshed with the sun gear 140, and a ring gear 148 which is meshed with the splitter gear 142.
Abstract:
A gas turbine engine has a fan, first and second compressor stages, first and second turbine stages. The first turbine stage drives the second compressor stage as a high spool. The second turbine stage drives the first compressor stage as part of a low spool. A gear train drives the fan with the low spool, such that the fan and first compressor stage rotate in the same direction. The high spool operates at higher pressures than the low spool. A lubrication system is also disclosed.
Abstract:
A gas turbine engine comprises a fan drive turbine for driving a gear reduction, which drives a fan rotor. A lubrication system supplies oil to the gear reduction. An oil tank is relatively small. The lubrication system operates to allow oil to remain in the oil tank for a dwell time of less than or equal to five seconds. A method of designing a gas turbine engine is also disclosed.
Abstract:
A method of assembling an epicyclic gear train includes the steps of providing a unitary carrier having a central axis that includes spaced apart walls and circumferentially spaced apart apertures provided at an outer circumference of the carrier. Gear pockets are provided between the walls and extend to the apertures, and a central opening in at least one of the walls. A plurality of intermediate gears is inserted through the central opening and move the intermediate gears radially outwardly into the gear pockets to extend through the apertures. A sun gear is inserted through the central opening. The plurality of intermediate gears is moved radially inwardly to engage the sun gear. A gear reduction is also disclosed.
Abstract:
A gas turbine engine includes a fan shaft and a support which supports at least a portion of the fan shaft. The support defines at least one of a support transverse and a support lateral stiffness. A gear system drives the fan shaft. A flexible support at least partially supports the gear system, and defines at least one of a flexible support transverse and a flexible support lateral stiffness with respect to at least one of the support transverse and the support lateral stiffness. An input to the gear system defines at least one of an input transverse and an input lateral stiffness with respect to at least one of the support transverse and the support lateral stiffness. A method of designing a gas turbine engine is also disclosed.
Abstract:
A gas turbine engine includes a shaft defining an axis of rotation. An outer turbine rotor directly drives the shaft and includes an outer set of blades. An inner turbine rotor has an inner set of blades interspersed with the outer set of blades. The inner turbine rotor is configured to rotate in an opposite direction about the axis of rotation from the outer turbine rotor. A splitter gear system couples the inner turbine rotor to the shaft and is configured to rotate the inner set of blades at a faster speed than the outer set of blades.
Abstract:
An example method of controlling performance of gearbox of a gas turbine engine includes establishing a gear characteristic of a plurality of double helical gears each disposed about a respective axis in a gearbox. Performance of the plurality of double helical gears is controlled by selecting a circumferential offset distance between a first plurality of gear teeth spaced apart from a second plurality of gear teeth on each of the plurality of double helical gears in response to the established gear characteristic.
Abstract:
A gas turbine engine includes a core engine, a fan section, and a superposition gearbox that includes a sun gear. A plurality of intermediate gears are engaged to the sun gear and supported in a carrier and a ring gear circumscribing the intermediate gears. The core engine drives the sun gear and an output from the superposition gearbox driving the fan section. An electric motor is coupled to a portion of the superposition gearbox to provide a portion of power to drive the fan section through the superposition gearbox.