Abstract: A gas turbine engine and method of starting, the gas turbine engine having a rotor comprising at least a shaft mounted compressor and turbine, with a casing surrounding the rotor. The method comprises an acceleration phase, a bowed-rotor cooling phase, during the acceleration, and a combustion phase. The bowed-rotor cooling phase comprises a time where the rotational speed of the rotor is maintained below a bowed-rotor threshold speed until a non-bowed condition is satisfied, wherein the air forced through the gas turbine engine cools the rotor. The combustion phase occurs after the bowed-rotor cooling phase and upon reaching the combustion speed, wherein fuel is supplied to the gas turbine engine is turned on.

Abstract: Systems and methods for indirect monitoring of combustor dynamics in a gas turbine engine include collecting vibration data acquired by a vibration sensor, which is mounted proximate to an operational component positioned relative to a combustor of a gas turbine engine. The vibration data can be transformed into a frequency domain representation at periodic intervals. The relative signal strength of the vibration data can be determined over the one or more identified frequency bands. The relative signal strength can be adjusted with hysteresis at each of the one or more identified frequency bands. Occurrence of a combustor dynamics event at one or more specific resonant frequencies can be determined based at least in part on evaluation of the adjusted relative signal strength relative to one or more event detection threshold levels.

Abstract: A gas turbine engine and method of starting, the gas turbine engine having a rotor comprising at least a shaft mounted compressor and turbine, with a casing surrounding the rotor. The method comprises an acceleration phase, a bowed-rotor cooling phase, during the acceleration, and a combustion phase. The bowed-rotor cooling phase comprises a time where the rotational speed of the rotor is maintained below a bowed-rotor threshold speed until a non-bowed condition is satisfied, wherein the air forced through the gas turbine engine cools the rotor. The combustion phase occurs after the bowed-rotor cooling phase and upon reaching the combustion speed, wherein fuel is supplied to the gas turbine engine is turned on.

Abstract: A method of operating a turbine engine that includes actuating a starter motor of the turbine engine such that a motoring speed of the turbine engine increases, and actuating a plurality of variable stator vanes of the turbine engine such that the plurality of variable stator vanes are at least partially open to control the motoring speed of the turbine engine.

Abstract: A method of starting a gas turbine engine having a rotor comprising at least a shaft-mounted compressor and turbine, with a casing surrounding the rotor includes an acceleration phase, a bowed-rotor cooling phase, during the acceleration, and a combustion phase. The bowed-rotor cooling phase comprises a time where the rotational speed of the rotor is maintained below a bowed-rotor threshold speed until a non-bowed condition is satisfied, wherein the air forced through the gas turbine engine cools the rotor. The combustion phase occurs after the bowed-rotor cooling phase and upon reaching the combustion speed, wherein fuel is supplied to the gas turbine engine.

Abstract: A start-up system including a control system controlling a partial opening of an air intake valve of a start-up turbine during a first phase of the start-up. The start-up turbine is capable of turning a rotor of the turbomachine for the purpose of the start-up, so as to prevent the rotor from encountering critical frequencies of the turbomachine.

Abstract: Systems and methods for indirect monitoring of combustor dynamics in a gas turbine engine include collecting vibration data acquired by a vibration sensor, which is mounted proximate to an operational component positioned relative to a combustor of a gas turbine engine. The vibration data can be transformed into a frequency domain representation at periodic intervals. The relative signal strength of the vibration data can be determined over the one or more identified frequency bands. The relative signal strength can be adjusted with hysteresis at each of the one or more identified frequency bands. Occurrence of a combustor dynamics event at one or more specific resonant frequencies can be determined based at least in part on evaluation of the adjusted relative signal strength relative to one or more event detection threshold levels.

Abstract: A method of operating a turbine engine that includes actuating a starter motor of the turbine engine such that a motoring speed of the turbine engine increases, and actuating a plurality of variable stator vanes of the turbine engine such that the plurality of variable stator vanes are at least partially open to control the motoring speed of the turbine engine.

Abstract: The present disclosure is directed to a system for monitoring an acoustic signal in a gas turbine engine. The system includes a gas turbine engine component that emits the acoustic signal. A microphone senses the acoustic signal and creates a microphone signal indicative of one or more characteristics of the acoustic signal. A controller receives the microphone signal and is configured to analyze the microphone signal to identify a gearbox event peak. If the gearbox event peak is present, the controller quantifies an amplitude of the gearbox event peak. The controller compares the amplitude of the gearbox event peak to a threshold to determine whether the gas turbine engine component needs maintenance.

Abstract: A method of starting a gas turbine engine having a rotor comprising at least a shaft mounted compressor and turbine, with a casing surrounding the rotor.