A method is provided of operating a single unducted rotor engine, the single unducted rotor engine comprising a single stage of unducted rotor blades. The method includes operating the single unducted rotor engine to define a flight speed, V.sub.0, in a length unit per second and an angular speed, n, in revolutions per second, the single stage of unducted rotor blades defining a diameter, D, in the length unit; wherein operating the single unducted rotor engine comprises operating the single unducted rotor engine to define an advance ratio greater than 3.8 while operating the single unducted rotor engine at a net efficiency of at least 0.8, the advance ratio defined by the equation V.sub.0/(nD).

A control device includes a reception unit configured to receive a load schedule indicating a load in the future of a combined cycle plant, a steam temperature control unit configured to control a temperature of steam flowing into a steam turbine, and a fuel control unit configured to control a flow rate of fuel supplied to a gas turbine. The steam temperature control unit is configured to output a command indicating an amount of operation for decreasing the temperature of the steam to a steam temperature regulator prior to a load decrease time at which the load is to be decreased in the load schedule.

The present disclosure provides a method and a system for controlling operation of an engine of an aircraft. The method comprises, at a controller of the engine, obtaining an actual engine output power for the engine, the actual engine output power based on a propeller rotation speed and a propeller blade pitch angle; converting the actual engine output power to a predicted thrust value; determining an actual engine power limit associated with a thrust limit of a propeller coupled to the engine from the predicted thrust value; and setting a maximum engine power limit of the engine using the actual engine power limit associated with the thrust limit of the propeller.

A control device for a gas turbine include: a target value calculation part configured to calculate a control target value being a target value of an output of the gas turbine; and a command value calculation part configured to calculate a fuel command value on the basis of a deviation between the control target value and an actual output value of the gas turbine. The target value calculation part is configured to: set the control target value to a value which is greater than an output demand value of the gas turbine immediately before a difference between the output demand value and the actual output value becomes not greater than a threshold; and subtract the control target value from the value after the difference becomes not greater than the threshold.

In one embodiment, a plant control apparatus controls a power plant that includes a combustor to burn fuel with oxygen introduced from an inlet guide vane to generate gas, a gas turbine driven by the gas from the combustor, a heat recovery steam generator to generate steam using heat of an exhaust gas from the gas turbine, and a steam turbine driven by the steam from the heat recovery steam generator. The apparatus controls an angle of the inlet guide vane before a start of the steam turbine to a first angle, controls the angle of the inlet guide vane after the start of the steam turbine to a second angle larger than the first angle, and reduce the angle of the inlet guide vane from the second angle to the first angle or more during the predetermined period.

An operational support device sets an execution time of overfiring serving as an operation of a power generation facility at an output higher than a rated output. The device includes a life index value acquisition unit that acquires a life index value at a start time, the life index value being an index indicating a life of the power generation facility and changing in value in one direction with the output of the power generation facility; an output pattern setting unit that sets an output pattern per unit time of the power generation facility from the start time to a stop time based on the life index value such that the life index value reaches a predetermined value; and an overfiring setting unit that sets, based on the output pattern, a time in a period from the start to the stop time at which the overfiring is to be performed.

A method of controlling a gas turbine engine capable of operating in at least a high, medium-high, medium, medium-low, and low output power ranges. The method includes during the medium-high output power range varying the angle of the variable guide vanes so that a third predetermined temperature of the combustor is maintained, during the medium output power range the variable guide vanes are closed and bleeding a gas from a downstream part of the compressor to an upstream part of the compressor so that a first predetermined temperature of the combustor is maintained, during the medium-low output power range the variable guide vanes are closed and bleeding a gas from a downstream part of the compressor to an upstream part of the compressor and bleeding a gas from the downstream part of the compressor to the exhaust so that a second predetermined temperature of the combustor is maintained.

Methods and systems for controlling an engine having a variable geometry mechanism are described. An output power of the engine is determined. A speed of the engine is determined. A temperature-independent position control signal for the variable geometry mechanism is generated based on a power-to-speed ratio, the power-to-speed ratio obtained by dividing the output power by the speed. The position control signal is output to a controller of the engine to control the variable geometry mechanism.

The present disclosure provides a method and a system for controlling operation of an engine of an aircraft. The method comprises, at a controller of the engine, obtaining an actual engine output power for the engine, the actual engine output power based on a propeller rotation speed and a propeller blade pitch angle; converting the actual engine output power to a predicted thrust value; determining an actual engine power limit associated with a thrust limit of a propeller coupled to the engine from the predicted thrust value; and setting a maximum engine power limit of the engine using the actual engine power limit associated with the thrust limit of the propeller.

Processes and apparatus for recovering energy from a petroleum, petrochemical, or chemical process are disclosed. The process comprises providing a fluid process stream in a petroleum, petrochemical, or chemical process zone having a direct current power input; controlling a flow rate of the process stream by directing at least a portion of the process stream through a first power-recovery turbine to generate electric power as direct current therefrom; and providing the recovered direct current to the direct current power input of the process zone.