The invention provides a CO.sub.2 turbine power generation system that can be easily prevented from reaching an overspeed condition. A CO.sub.2 turbine power generation system of an embodiment includes a CO.sub.2 medium shutoff valve installed in a medium flow path between a regenerative heat exchanger and a combustor. When load rejection is to be performed, the CO.sub.2 medium shutoff valve closes to shut off the supply of the medium from the regenerative heat exchanger to the combustor.

The invention relates to a fuel supply system of a turbomachine, including a fuel circuit having a pressurizing means at the outlet of the circuit, a pump arranged to send a flow of fuel into the circuit, and a flow sensor placed in a fuel supply duct between an outlet of the pump and the pressurizing means. The fuel circuit includes a device for regulating a flow cross section between the pump and the flow sensor, the device being activated by control means, the shaft of the pump being associated with detection means recording a speed of rotation of the shaft, and, if these detection means record a speed of rotation above a variable predetermined threshold, the regulating device is activated in order to reduce the flow sent to the flow sensor.

An emergency shut-off device shuts off supply of control oil to a trip-and-throttle valve of a steam turbine and closes the trip-and-throttle valve in an emergency. The emergency shut-off device includes: a cylinder; a piston that slides into the cylinder; a spring that applies a biasing force to the piston; a plurality of piston valves disposed on the piston; and a plurality of chambers that are formed by the piston valves. The control oil is supplied to and drained from the plurality of chambers, and a sliding surface of each of the piston valves has a groove to leak the control oil in a corresponding one of the chambers to another one of the chambers that is adjacent to the corresponding chamber in an axis direction.

A method and decoupler for disengaging an output member from an engine in a back drive event with a backdrive decoupler. The backdrive decoupler includes a shaft and a retention mechanism selectively coupling the output member to the shaft. In a backdrive event, the decoupler decouples the member from a drive shaft.

A turbomachine, a computing system for a turbomachine, and a method for overspeed protection are provided. The turbomachine includes a first rotor assembly interdigitated with a second rotor assembly together operably coupled to a gear assembly. A plurality of sensors is configured to receive rotor state data indicative of one or more of a speed, geometric dimension, or capacitance, or change thereof, or rate of change thereof, relative to the first rotor assembly or the second rotor assembly. A controller executes operations including receiving rotor state data from the plurality of sensors; comparing rotor state data to one or more rotor state limits; and contacting one or more of the first rotor assembly or the second rotor assembly to a contact surface adjacent to the respective first rotor assembly or the second rotor assembly if the rotor state data exceeds the rotor state limit.

A control system is provided for a turbine valve. The turbine valve has a first coil and a second coil to control or sense movement of a mechanical valve positioner. Two valve positioners are provided with each valve positioner having two drive circuits to drive the first and second coils. Switches are provided such that only one drive circuit is connected to each coil at a time. The control system may also include a hydraulic pilot valve section and a main hydraulic valve section. Feedbacks are used to determine a pilot valve error and a main valve error which are combined to determine a turbine valve error. The turbine valve error is repeatedly determined to minimize the error.

A hydraulic lock apparatus includes a hydraulic actuator, a pressure storage device connected to the hydraulic actuator, and a control valve configured to actuate to a first position and a second position. The control valve fluidly isolates the pressure storage device from the hydraulic actuator when the control valve is in the first position. The control valve fluidly connects the pressure storage device to the hydraulic actuator when the control valve is in the second position.

An exemplary aircraft includes a turbine engine having a gas generator spool and a power spool, the power spool operational to drive a rotor, a first generator coupled to the gas generator spool, and a controller operable to increase a load on the gas generator spool when the gas generator spool is on a speed limit thereby increasing a speed limit margin in order to increase power available from the turbine engine.

An engine system of an aircraft includes a gas turbine engine comprising at least one spool and at least one electric machine operably coupled with the at least one spool. A controller is configured to detect if the at least one spool of the gas turbine engine is in or is approaching an overspeed condition and apply a load to the at least one spool via the at least one electric machine.

The method can include monitoring a current value of a rate of reduction of rotation speed of the shaft; providing a threshold value of a rate of reduction of rotation speed of the shaft; and generating a signal indicative of the shaft shear event when the current value exceeds threshold value.