Abstract: A gas turbine engine including a rotating shaft and a bearing assembly. The bearing assembly is configured to support the rotating shaft. The bearing assembly has a first bearing and a second bearing. The first bearing is configured to support an axial load of the rotating shaft when a forward thrust of the rotating shaft is greater than ten percent. The second bearing is configured to support the axial load of the rotating shaft when a thrust of the rotating shaft is between ten percent forward thrust and ten percent aft thrust, inclusive of the end points.

Abstract: A gas turbine engine including a rotating shaft and a bearing assembly. The bearing assembly is configured to support the rotating shaft. The bearing assembly has a first bearing and a second bearing. The first bearing is configured to support an axial load of the rotating shaft when a forward thrust of the rotating shaft is greater than ten percent. The second bearing is configured to support the axial load of the rotating shaft when a thrust of the rotating shaft is between ten percent forward thrust and ten percent aft thrust, inclusive of the end points.

Abstract: A gas turbine engine includes a compressor rotor shaft assembly, an accessory gearbox, and a bowed-rotor mitigation drive device drivingly coupled with the accessory gearbox. The bowed-rotor mitigation drive device is driven during an engine startup phase so as to induce a mechanical load (mechanical energy) to the bowed-rotor mitigation drive device. The mechanical load (mechanical energy) is retained within the bowed-rotor mitigation drive device during operation of the gas turbine engine. The mechanical load (mechanical energy) retained within the bowed-rotor mitigation drive device is periodically released by the bowed-rotor mitigation drive device in a plurality of periods so as to provide, in each period, a driving force to the accessory gearbox, which provides the driving force to the compressor rotor shaft assembly to periodically rotate the compressor rotor shaft assembly.

Abstract: A gas turbine engine includes a compressor rotor shaft assembly, an accessory gearbox, and a bowed-rotor mitigation drive device drivingly coupled with the accessory gearbox. The bowed-rotor mitigation drive device is driven during an engine startup phase so as to induce a mechanical load (mechanical energy) to the bowed-rotor mitigation drive device. The mechanical load (mechanical energy) is retained within the bowed-rotor mitigation drive device during operation of the gas turbine engine. The mechanical load (mechanical energy) retained within the bowed-rotor mitigation drive device is periodically released by the bowed-rotor mitigation drive device in a plurality of periods so as to provide, in each period, a driving force to the accessory gearbox, which provides the driving force to the compressor rotor shaft assembly to periodically rotate the compressor rotor shaft assembly.

Abstract: A device for balancing a shaft in a turbomachine engine includes an annular insert configured to be positioned inside the shaft at any axial position along the shaft, and a weight that is attached to the annular insert at any angular position inside the shaft.

Abstract: A controllable magneto-rheological device includes an annular cylinder formed by inner and outer walls connected at first and second opposing ends and forming an inner shaft configured to receive an operational component of an engine, generator or other device including one or more rotating structures. A magneto-rheological fluid is provided to fill a volume between the inner and outer walls of the annular cylinder. A plurality of electro-magnetic coils are positioned around the outer wall of the annular cylinder. One or more current controllers are coupled to the plurality of electro-magnetic coils for introducing a current through each of the electro-magnetic coils and corresponding magnetic flux through the magneto-rheological fluid. A level of current provided to each of the plurality of electro-magnetic coils directly affects the viscosity of the magneto-rheological fluid and thus the stiffness and damping levels of the controllable magneto-rheological device.

Abstract: A controllable magneto-rheological device includes an annular cylinder formed by inner and outer walls connected at first and second opposing ends and forming an inner shaft configured to receive an operational component of an engine, generator or other device including one or more rotating structures. A magneto-rheological fluid is provided to fill a volume between the inner and outer walls of the annular cylinder. A plurality of electro-magnetic coils are positioned around the outer wall of the annular cylinder. One or more current controllers are coupled to the plurality of electro-magnetic coils for introducing a current through each of the electro-magnetic coils and corresponding magnetic flux through the magneto-rheological fluid. A level of current provided to each of the plurality of electro-magnetic coils directly affects the viscosity of the magneto-rheological fluid and thus the stiffness and damping levels of the controllable magneto-rheological device.