A turbine clearance control system is provided. The turbine clearance control system includes a cooling air source and a turbine casing surrounding a portion of a turbine, wherein the turbine casing defines an integral cooling duct within the turbine casing, the integral cooling duct including apertures on an interior surface of the turbine casing.

A turbine clearance control system is provided. The turbine clearance control system includes a cooling air source and a turbine casing surrounding a portion of a turbine, wherein the turbine casing defines an integral cooling duct within the turbine casing, the integral cooling duct including apertures on an interior surface of the turbine casing.

A system for controlling blade tip clearances in a gas turbine engine may comprise an active clearance control system and a controller in operable communication with the active clearance control system. The controller may be configured to identify a cruise condition, reduce a thrust limit of the gas turbine engine to a de-rated maximum climb thrust, determine a first target tip clearance based on the de-rated maximum climb thrust, and send a command signal correlating to the first target tip clearance to the active clearance control system.

A system for controlling blade clearances within a gas turbine engine includes a rotor disk and a rotor blade coupled to the rotor disk. Additionally, the system includes an outer turbine component positioned outward of the rotor blade such that a clearance is defined between the rotor blade and the outer turbine component. Furthermore, the system includes a heat exchanger configured to receive a flow of cooling air bled from the gas turbine engine and transfer heat from the received flow of the cooling air to a flow of coolant to generate cooled cooling air. Moreover, the system includes a valve configured to control the flow of the coolant to the heat exchanger. In this respect, the cooled cooling air is supplied to at least one of the rotor disk or the rotor blade to adjust the clearance between the rotor blade and the outer turbine component.

A system for controlling blade clearances within a gas turbine engine includes a rotor disk and a rotor blade coupled to the rotor disk. Additionally, the system includes an outer turbine component positioned outward of the rotor blade such that a clearance is defined between the rotor blade and the outer turbine component. Furthermore, the system includes a heat exchanger configured to receive a flow of cooling air bled from the gas turbine engine and transfer heat from the received flow of the cooling air to a flow of coolant to generate cooled cooling air. Moreover, the system includes a valve configured to control the flow of the coolant to the heat exchanger. In this respect, the cooled cooling air is supplied to at least one of the rotor disk or the rotor blade to adjust the clearance between the rotor blade and the outer turbine component.

A system has first and second fuel stores for first and second fuels, an engine, a fuel distribution system, first and second flow rates of the fuel contributing to a total flow rate of fuel; and a controller for controlling the relative fractions of the total flow rate of fuel to the engine according to the required power output of the engine such that the relative fraction of the total flow rate of fuel to the engine represented by the second flow rate increases with increasing required power output of the engine. The fuels are selected such that using only the second fuel results in a lower engine temperature than using only the first fuel, for the same mechanical power and/or the second fuel has a lower specific energy than the first and/or the second fuel produces more water during combustion than the first fuel per unit of fuel energy.

A system comprises first and second first fuel stores, an engine arranged to produce mechanical power, a fuel distribution system arranged to deliver fuel from the first and second fuel stores to the engine, the first fuel delivered at a first mass flow rate, the second fuel delivered at a second mass flow rate, the first and second mass flow rates contributing to a total mass flow rate of fuel to the engine, and a control system arranged to increase the relative fraction of the total mass flow rate of fuel represented by the second mass flow rate during a period of acceleration of the engine, in order to control a surge margin of the engine. The second fuel is selected to have a higher specific energy than the first fuel and to release a greater mass of water per unit mass of fuel than the first fuel.

An engine system comprises a first fuel store, a second fuel store, an engine arranged to produce mechanical power by combustion or oxidation of a fuel in an engine, a fuel distribution system arranged to deliver fuel from the first and second fuel stores to the engine, the first fuel delivered at a first mass flow rate, the second fuel delivered at a second mass flow rate, the first and second mass flow rates contributing to a total mass flow rate of fuel to the engine; and a control system arranged to control the relative fractions of the total mass flow rate of fuel to the engine represented by the first mass flow rate and the second mass flow rate, based on an engine temperature.

An air-jet cooling device for a casing of a turbomachine, in particular a turbine casing, including a cooling air housing having a wall, and a tube having a first end mounted on the wall of the housing so as to put the tube into fluid communication with the housing, orifices being formed in a wall of the tube in order to eject the cooling air coming from the housing on the casing. The tube has a section at the first end with a gradual variation that defines a boss. The boss has a curved surface to be immersed in the cooling air so as to avoid a detachment of a boundary layer of the cooling air at an interface between the first end of the tube and the housing.

A device for controlling clearance between the tips of rotating blades of an aircraft turbomachine and a casing. An air circulation path allows air to be blown onto the casing in order to change its temperature. In addition, heating means heat the circulating air.