A method for extending an operating window of an operating mode of a gas turbine engine includes monitoring operating conditions of the gas turbine engine. The gas turbine engine is prevented by the method from transitioning from the first operating mode up to a second operating mode. A bulk temperature demand of the gas turbine engine is adjusted by a predefined amount to generate a first biased bulk temperature demand. The adjustment includes applying a first incremental bias to a bulk flame temperature schedule. The operation of the gas turbine engine is then adjusted based on the first biased bulk temperature demand. The monitored operating conditions are analyzed to determine whether one of the operating conditions has reached a threshold value.

This system for purging a fuel containing hydrogen comprises a gas turbine. The gas turbine comprises at least one combustion chamber (20) provided with at least one injector (52) of the fuel, an exhaust section and a hot gas circuit going from the combustion chamber (20) to the exhaust section. The system comprises at least one point of injection (A, A′) of air and/or of inert gas positioned on the hot gas circuit.

A speed control system and a power load balance detector for a turbine is provided. The speed control system includes a speed wheel with a plurality of teeth. A timer stores a time stamp when each of the teeth passes by a speed probe. A first speed estimate is determined for overspeed protection, and a second speed estimate is determined for operational speed control. The power load balance detector trips or shuts down the turbine when an unbalance is above a first threshold and the speed of the turbine is above a second threshold.

A bleed valve assembly includes a flow duct with an inlet and an outlet disposed downstream from the inlet. The outlet is smaller in cross-sectional area than a region of the flow duct disposed between the inlet and the outlet. A piston housing is disposed inside the flow duct between the inlet and the outlet so as to form an annular flow passage between the flow duct and the piston housing. The piston housing is axially aligned with a center axis of the flow duct. At least one rib extends between the flow duct and the piston housing. A sleeve piston is disposed inside the piston housing and is configured to extend downstream of the piston housing in a closed position. The sleeve piston comprises an outer wall that is at least the same in cross-sectional area as the outlet of the flow duct.

A bleed valve assembly includes a flow duct with an inlet and an outlet disposed downstream from the inlet. The outlet is smaller in cross-sectional area than a region of the flow duct disposed between the inlet and the outlet. A piston housing is disposed inside the flow duct between the inlet and the outlet so as to form an annular flow passage between the flow duct and the piston housing. The piston housing is axially aligned with a center axis of the flow duct. At least one rib extends between the flow duct and the piston housing. A sleeve piston is disposed inside the piston housing and is configured to extend downstream of the piston housing in a closed position. The sleeve piston comprises an outer wall that is at least the same in cross-sectional area as the outlet of the flow duct.

Methods and systems for controlling a bleed-off valve of a gas turbine engine are described. The method comprises maintaining a first bleed-off valve associated with a first compressor of the gas turbine engine at least partially open upon detection of an unintended engine disturbance causing a drop in pressure of a combustion chamber of the engine; monitoring a rotor acceleration of the first compressor; and controlling closure of the first bleed-off valve when the rotor acceleration of the first compressor reaches a first threshold for a first duration.

A combustion control device including a bleed valve control unit for controlling a bleed valve disposed on a bleed pipe for performing bleeding so that a part of the compressed air flowing into the casing is not used as combustion air in the combustor, a fuel control unit for controlling a fuel regulating valve for regulating a fuel flow rate of fuel supplied to the combustor, and a temperature acquisition unit. Upon reception of a load rejection signal for cutting off a load from the gas turbine, the bleed valve control unit controls a valve opening degree of the bleed valve from a closed state to an open state with a prescribed opening degree, and the fuel control unit controls the fuel regulating valve such that the acquired flame temperature falls within a predetermined temperature range defined by an upper limit value and a lower limit value.

A system has: a combustor; a plenum surrounding the combustor; a transfer tube having an inlet fluidly connected to the plenum and at least two outlets, a first flow passageway defined between the inlet and a first outlet, a second flow passageway defined between the inlet and a second outlet, the second flow passageway connected to a discharge region outside of the plenum; a flow valve disposed within the second flow passageway and operable between an open position and a closed position, in the open position the flow valve fluidly connects the plenum with the discharge region, in the closed position the flow valve blocking fluid communication between the plenum and the discharge region; and a controller communicatively coupled to the flow valve to control operation thereof by: causing the flow valve to open for a time period; and subsequent to the time period, causing the flow valve to close.

A system has: a combustor; a plenum surrounding the combustor; a transfer tube having an inlet fluidly connected to the plenum and at least two outlets, a first flow passageway defined between the inlet and a first outlet, a second flow passageway defined between the inlet and a second outlet, the second flow passageway connected to a discharge region outside of the plenum; a flow valve disposed within the second flow passageway and operable between an open position and a closed position, in the open position the flow valve fluidly connects the plenum with the discharge region, in the closed position the flow valve blocking fluid communication between the plenum and the discharge region; and a controller communicatively coupled to the flow valve to control operation thereof by: causing the flow valve to open for a time period; and subsequent to the time period, causing the flow valve to close.

An engine system for an aircraft includes a first gas turbine engine, a second gas turbine engine, and a control system. The control system is configured to operate the first gas turbine engine with an idle fuel burn schedule in a taxi mode of the aircraft and dry crank the second gas turbine engine in a first pre-takeoff portion of the taxi mode to cool the second gas turbine engine absent fuel burn by the second gas turbine engine. The control system operates the second gas turbine engine with a sub-idle fuel burn schedule in a second pre-takeoff portion of the taxi mode of the aircraft. The sub-idle fuel burn schedule includes a reduction of the idle fuel burn schedule. A fuel flow of the first gas turbine engine and the second gas turbine engine is increased above the idle fuel burn schedule prior to takeoff of the aircraft.