A method of controlling an operating temperature of a first combustion zone of a combustor of a rotary machine includes determining a current operating temperature and a target operating temperature of a first combustion zone using a digital simulation. The method further includes determining a derivative of the current operating temperature with respect to a current fuel split using the digital simulation. The fuel split apportions a total flow of fuel to the combustor between the first combustion zone and a second combustion zone. The method also includes calculating a calculated fuel split that results in a calculated operating temperature approaching the target operating temperature. The method further includes channeling a first flow of fuel to the first combustion zone and a second flow of fuel to the second combustion zone.

A method of operating a rotary machine below a minimum emissions compliance load in a response mode includes reducing a fuel split to zero. The fuel split apportions a total flow of fuel to the combustor between a first combustion zone and a second combustion zone. The method also includes determining a current operating temperature of the first combustion zone using a digital simulation of the rotary machine. The method further includes determining a target operating temperature of the first combustion zone. The target operating temperature enables the rotary machine to operate below a traditional Minimum Emissions Compliance Load (MECL) while still in compliance with emissions standards. The method also includes channeling a first flow of fuel to the first combustion zone. The first flow of fuel decreases the temperature of the first combustion zone to the target operating temperature.

A passive flow splitting system for use in a turbine engine control system to provide split fuel flow to two fuel manifolds to supply primary and secondary fuel injectors for the particular combustion zones thereof utilizing intentionally different split ratios dependent on ascending or descending combustion fuel flow is provided. The system includes a passive fuel divider valve (FDV) that includes a primary piston and a secondary piston. The primary piston is moveable independently from the secondary piston during a portion of its stroke, and is hydro-locked to the secondary piston during another portion of its stroke. An ecology valve is also provided to purge the fuel from the primary and/or secondary manifolds during different modes of operation. A transfer valve is included to control the position of ecology piston of the ecology valve.

A passive flow splitting system for use in a turbine engine control system to provide split fuel flow to two fuel manifolds to supply primary and secondary fuel injectors for the particular combustion zones thereof utilizing intentionally different split ratios dependent on ascending or descending combustion fuel flow is provided. The system includes a passive fuel divider valve (FDV) that includes a primary piston and a secondary piston. The primary piston is moveable independently from the secondary piston during a portion of its stroke, and is hydro-locked to the secondary piston during another portion of its stroke. An ecology valve is also provided to purge the fuel from the primary and/or secondary manifolds during different modes of operation. A transfer valve is included to control the position of ecology piston of the ecology valve.

A method of controlling an operating temperature of a first combustion zone of a combustor of a rotary machine includes determining a current operating temperature and a target operating temperature of a first combustion zone using a digital simulation. The method further includes determining a derivative of the current operating temperature with respect to a current fuel split using the digital simulation. The fuel split apportions a total flow of fuel to the combustor between the first combustion zone and a second combustion zone. The method also includes calculating a calculated fuel split that results in a calculated operating temperature approaching the target operating temperature. The method further includes channeling a first flow of fuel to the first combustion zone and a second flow of fuel to the second combustion zone.

A gas turbine engine includes an engine core having a compressor, a combustor fluidly connected to the compressor, and a turbine fluidly connected to the combustor. A core nacelle is disposed radially outward of the engine core. A cavity is disposed between an inner surface of the core nacelle and an outer surface of the engine core. The cavity includes a vent disposed at an aft end. The vent includes at least one flap configured to be maintained in an unrestricted position and in a restricted position. An actuator is configured to control the position of the at least one flap.

A gas turbine engine includes an engine core having a compressor, a combustor fluidly connected to the compressor, and a turbine fluidly connected to the combustor. A core nacelle is disposed radially outward of the engine core. A cavity is disposed between an inner surface of the core nacelle and an outer surface of the engine core. The cavity includes a vent disposed at an aft end. The vent includes at least one flap configured to be maintained in an unrestricted position and in a restricted position. An actuator is configured to control the position of the at least one flap.

A method for reducing an engine core speed is disclosed, which includes determining a condition of an engine during operation of the engine, and controlling an engine turbine clearance based on the condition of the engine so as to influence the engine core speed. An engine system comprising an engine core speed reducing system is also disclosed.

A method for reducing an engine core speed is disclosed, which includes determining a condition of an engine during operation of the engine, and controlling an engine turbine clearance based on the condition of the engine so as to influence the engine core speed. An engine system comprising an engine core speed reducing system is also disclosed.

An assembly of a servo pump and a hydraulic motor. The assembly has a housing which contains the pump and the motor. The motor has a rotating body which rotates under the motive power of a pressurised motor liquid flow. The motor has a high pressure region which receives the pressurised motor liquid flow, and a low pressure region through which the motor liquid flow leaves the motor. The pump also has a rotating body. The pump has a low pressure region which receives servo liquid flow to be pumped by its rotating body, and a high pressure region through which pressurised servo liquid flow leaves the pump. Each rotating body is mounted on a respective journal.