Abstract: A method and system for cleaning a fuel nozzle during engine operation is provided. Operations include operating the compressor section to provide the flow of oxidizer at a first oxidizer flow condition to the combustion chamber, wherein the first oxidizer flow condition comprises an environmental parameter; operating the fuel system at a first fuel flow condition to produce a fuel-oxidizer ratio at the combustion chamber; comparing the environmental parameter to a first environmental parameter threshold; and transitioning the fuel system to a second fuel flow condition corresponding to a cleaning condition at the fuel nozzle if the environmental parameter is equal to or greater than the first environmental threshold.

Abstract: An apparatus is provided for a turbine engine. This apparatus includes a fuel conduit and a fuel nozzle. The fuel conduit includes a supply passage. The fuel nozzle includes a nozzle passage, an end wall and a nozzle orifice. The nozzle passage has a longitudinal centerline and extends longitudinally through the fuel nozzle along the longitudinal centerline from the end wall to the nozzle orifice. The nozzle passage is configured with a convergent portion and a throat portion. The nozzle passage converges radially inward towards the longitudinal centerline as the convergent portion extends longitudinally along the longitudinal centerline away from the end wall and towards the throat portion. The supply passage is fluidly coupled to the nozzle passage by a fuel aperture in the end wall. A centerline of the fuel aperture is angularly and laterally offset from the longitudinal centerline.

Abstract: A fluid flow system includes a main valve having a spool, a first chamber, and a second chamber. A pressure difference between the first chamber and the second chamber is configured to move the spool to control fluid flow. An electromechanical meter interface device (EMID) is in fluid communication with at least one of the first and second chambers of the main valve. The EMID is configured to meter fluid from a first source and a second source to the at least one of the first chamber and the second chamber. The first source has a different pressure from the second source. A fixed orifice is arranged between the main valve and the EMID. A fuel system for a gas turbine engine is also disclosed.

Abstract: A cooling arrangement for a gas turbine engine according to an example of the present disclosure includes, among other things, an offtake duct that has an offtake inlet coupled to a cooling source, the offtake duct defining a throat, and a valve downstream of the throat. The valve couples the offtake duct and a first cooling flow path. The valve is operable to selectively modulate flow through the offtake duct. A bleed passage includes a bleed inlet coupling the offtake duct and a second cooling flow path. The bleed inlet is defined at a location between the offtake inlet and the throat, inclusive. A method of cooling a propulsion system is also disclosed.

Abstract: An Electronic Engine Controller (EEC) for a gas turbine engine. The EEC is configured to be connected to a solenoid valve, and configured to control the solenoid valve by providing a driving signal to either a first solenoid winding or a second solenoid winding of the solenoid valve, the first and second solenoid windings being magnetically coupled to one another by an armature of the solenoid valve. The armature is movable under the action of the driving signal to operate the solenoid valve. The solenoid winding of the first and second solenoid windings provided with the driving signal is a driving winding and the other solenoid winding of the first and second solenoid windings is a pick-up winding. When the EEC controls the solenoid valve via the driving winding by providing the driving signal thereto, it is further configured to sense a position of the solenoid valve via the pick-up winding by detecting a signal induced in the pick-up winding by the magnetic coupling.

Abstract: Methods and systems for operating an engine, the engine having an engine core, an exhaust nozzle, and variable geometry mechanisms, are provided. A request for an increase in thrust generated by the engine is received. In response to receipt of the request, it is determined that at least one operating condition for engine degradation thrust is met. In response to this determination, the variable geometry mechanisms are modulated to degrade an efficiency of the engine, thereby increasing a temperature of core air flowing through the engine core. The increase in thrust is generated from the increased temperature of the core air flowing through the engine core and into the exhaust nozzle.

Abstract: A method for operating a hybrid-electric gas turbine engine is provided. The method includes: receiving data indicative of an actual rotational speed of a shaft; calculating an error between the actual rotational speed of the shaft and a commanded rotational speed of the shaft; providing the calculated error to a fuel flow control circuit operable with a fuel delivery system of the hybrid-electric propulsion engine; providing the calculated error to an electric machine control circuit operable with an electric machine of the hybrid-electric propulsion engine, the electric machine drivingly coupled to the shaft; and modifying a torque on the shaft from the electric machine with the electric machine control circuit based on the calculated error.

Abstract: Disclosed herein is an apparatus. The apparatus comprises an injector coupled to a head portion of a combustion chamber, the injector comprising a plurality of injector elements distributed away from an inner annulus and in an outer annulus. A geometry of combustion chamber comprises a body portion, an optional shoulder portion, and a throat portion. An inner wall of combustion chamber converges radially inward towards the throat. The plurality of injector elements in combination with the geometry of the combustion chamber are configured to confine a predetermined percentage of mass flow associated with combustion to a predetermined outer annulus of the chamber.

Abstract: A gas turbine including a fuel gas supply system to supply fuel gas via a fuel piping to a gas turbine combustor, a pressure control valve installed halfway along the fuel piping, a flow control valve installed in the fuel piping at downstream of the pressure control valve, and a control device configured that in a case where a flow rate change occurs in the fuel gas flowing through the fuel gas supply system, along with a tendency of change in an opening degree of the pressure control valve or a pressure P1 at upstream of the pressure control valve, a command value of the flow rate of the fuel gas that is determined based on a demand value of a gas turbine load is adjusted so that the change is suppressed in the opening degree of the pressure control valve or the pressure P1.

Abstract: A cooling system for a plurality of conductive cables in a gas turbine engine includes a cooling source and an electric motor disposed in a tail cone. The cooling source may comprise an electric fan or an oil pump. The cooling source may be configured for active cooling of the plurality of conductive cables. The electric fan may be in fluid communication with ambient air during operation of the gas turbine engine.

Abstract: In a method for operating an engine, a request for an increase in thrust generated by the engine is received. In response to receipt of the request, a determination is made as to whether at least one operating condition for heat application-based thrust is met. If so, a heat source is applied to heat bypass air flowing through the bypass duct towards the exhaust nozzle and the increase in thrust is generated from an increased temperature of mixed bypass air and core air at the exhaust nozzle.

Abstract: A premixer for a combustor includes: a centerbody having a hollow interior cavity; a swirler assembly radially outward of the centerbody; a peripheral wall disposed radially outward of the centerbody and the swirler assembly such that a mixing duct is defined between the peripheral wall and the centerbody, downstream from the swirler assembly; an annular splitter radially inward of the swirler assembly and radially outward of the centerbody such that a radial gap is defined between the splitter and an outer surface of the centerbody, wherein the splitter includes a trailing edge which extends axially aft of the swirler assembly; a fuel gallery disposed inside the interior cavity of the centerbody; and at least one fuel injector extending outward from the fuel gallery and passing through an injector port communicating with the outer surface of the splitter.

Abstract: The present application discloses a method of determining one or more fuel characteristics of an aviation fuel used for powering a gas turbine engine of an aircraft. The method comprises: determining one or more performance parameters of the gas turbine engine during a first time period of operation of the gas turbine engine; and determining one or more fuel characteristics of the fuel based on the one or more performance parameters. A method of operating an aircraft, a fuel characteristic determination system, and an aircraft are also disclosed.

Abstract: A method of repairing a component of a gas turbine engine in situ, wherein the component includes a deposit, includes directing a flow of gas, which may be an oxygen-containing gas, to the deposit of the component; and heating the component including the deposit while the component is installed in the gas turbine engine and for a duration sufficient to substantially remove the deposit.

Abstract: A gas turbine combustor includes a burner composed of a fuel nozzle group having a plurality of fuel nozzles for fuel supply, a fuel nozzle plate structurally supporting the fuel nozzles and serving to distribute the fuel flowing from an upstream side to the fuel nozzles, and a perforated plate located downstream of the fuel nozzles and having nozzle holes corresponding to the fuel nozzles. The fuel nozzle group includes outer circumferential fuel nozzles and inner circumferential fuel nozzles. Each outer diameter of at least a proximal end of the outer circumferential fuel nozzles is larger than that of the inner circumferential fuel nozzles.

Abstract: A core duct assembly for a gas turbine engine includes a core duct including an outer and an inner wall, the outer wall having an interior surface; a gas flow path member extending across the gas flow path at least partly between the inner and outer walls, the rotor blade having a radial span extending from a blade platform to a blade tip, wherein an upstream wall axis is defined as an axis tangential to a point on a first portion of the interior surface of the outer wall of the core duct extending downstream from the gas flow path member, the upstream wall axis lying in a longitudinal plane of the gas turbine engine containing the rotational axis of the engine, and wherein the upstream wall axis intersects the rotor blade at a point spaced radially inward from the blade tip of the rotor blade.

Abstract: An apparatus for use in a gas turbine engine is disclosed comprising a bleed valve and an intermediate valve. In use the bleed valve is exposed to a source of pressurised air, and the bleed valve is movable between an open position, in which the bleed valve permits a flow of the pressurised air through the bleed valve and a closed position, in which the bleed valve does not permit a flow of the pressurised air through the bleed valve. The intermediate valve is operatively connected to the bleed valve and configured to selectively open and close the bleed valve, wherein the intermediate valve is configured in a mode of operation to close the bleed valve based on the pressurised air within the bleed valve exceeding a predetermined threshold.

Abstract: A system includes a flow inlet conduit. A primary conduit branches from the flow inlet conduit for delivering flow to a set of primary nozzles. An equalization bypass valve (EBV) connects between the flow inlet conduit and a secondary conduit for delivering flow to a set of secondary nozzles. The EBV is connected to be controlled to apportion flow from the flow inlet conduit to the secondary conduit. A secondary equalization valve (SEV) connects between the flow inlet conduit and the secondary conduit. The SEV is connected to be controlled by drain pressure (PD) to apportion flow from the flow inlet conduit to the secondary conduit.

Abstract: An aircraft including lean-burn gas turbine engines operating in pilot-plus-mains mode with a given initial fuel flow W0, a method of controlling the optical depth of contrails produced by a first group of engines includes the steps of (i) reducing fuel flow to each engine in the first group to change the operation of each engine from pilot-plus-mains mode to pilot-only mode, and (ii) adjusting fuel flow to one or more engines in a second group of engines such that the total fuel flow to engines of the second group is increased, all engines of the second group remaining in pilot-plus-mains mode, and wherein the set of lean-burn engines consists of the first and second groups. Depending on atmospheric conditions, the average optical depth of contrails produced by the engines may be enhanced or reduced compared to when all engines operate in pilot-plus-mains mode with a fuel flow W0.

Abstract: A method of determining a calorific value of fuel supplied to a gas turbine engine of an aircraft comprises sensing at least one engine parameter during a first time period of aircraft operation during which the gas turbine engine uses the fuel; and, based on the at least one sensed engine parameter, determining a calorific value of the fuel. The sensing may be repeated such that the at least one engine parameter is monitored over time. The gas turbine engine may be a propulsive gas turbine engine of the aircraft or a gas turbine engine of an auxiliary power unit of the aircraft.