Abstract: A gas turbine engine includes an engine core and a fan located upstream of the engine core. The engine core includes: a compressor system including first, lower pressure compressor, and second, higher pressure compressor; and an outer core casing surrounding the compressor system and including a first flange connection arranged to allow separation of the outer core casing at an axial position of the first flange connection. The first flange connection is the first flange connection that is downstream of an axial position defined by the axial midpoint between the mid-span axial location on the trailing edge of the most downstream aerofoil of the first compressor and the mid-span axial location on the leading edge of the most upstream aerofoil of the second compressor. A fan diameter ratio of: first ? ? flange ? ? radius fan ? ? diameter is equal to or greater than 0.125.

Abstract: A multi-flow turbojet engine generally includes an upstream ducted fan driven by a gas generator, the gas generator having a first and a second compressor, which are coaxial, an inlet case forming a support for the rotors of the upstream ducted fan and of the first compressor, an inter-compressor case downstream of the inlet casing and forming a support for the rotors of the second compressor, attachment means for thrust take-up rods, which attachment means are arranged on the inter-compressor case. The turbojet engine includes at least one axial stress transmission rod for connecting the inlet case to the inter-compressor case.

Abstract: A liquid rocket engine integrates tap-off openings at a combustion chamber wall to direct exhaust from the combustion chamber to a tap-off manifold that provides the exhaust to one or more auxiliary systems, such as a turbopump that pumps oxygen and/or fuel into the combustion chamber. The tap-off opening passes through a fuel channel formed in that combustion chamber exterior wall and receives fuel through a fuel opening that interfaces the fuel channel and tap-off opening. The tap-off manifold nests within a fuel manifold for thermal management. The fuel channel directs fuel into the combustion chamber through fuel port openings formed in the combustion chamber, the fuel port openings located closer to a headend of the combustion chamber than the tap-off openings.

Abstract: A gas turbine engine includes an engine core including: a compressor system including first, lower pressure compressor, and second, higher pressure compressor; and an outer core casing. The engine includes a front mount arranged for connection to a pylon; and a fan located upstream of the engine core. The outer core casing includes a first flange connection that: is arranged to allow separation of the outer core casing at an axial position thereof, and is the first flange connection downstream of an axial position defined by the axial midpoint between the mid-span axial location on trailing edge of the most downstream aerofoil of first compressor and mid-span axial location on leading edge of the most upstream aerofoil of the second compressor. A front mount position ratio of: axial ? ? distance ? ? between ? ? the ? ? first ? ? flange ? ? connection and ? ? the ? ? front ? ? mount first ? ? flange ? ? radius is equal to or less than 1.18.

Abstract: The invention provides a pneumatic circuit for supplying air to at least one discharge valve that is pneumatically actuated and to at least one depressurizing device for depressurizing an oil enclosure in a turbine engine, the pneumatic circuit comprising: a pneumatic control unit having at least one solenoid valve supplying compressed air to a discharge valve of a compressor of the turbine engine; at least one depressurizing device for depressurizing an oil enclosure of the turbine engine, the device including a compressed air ejector for depressurizing the oil enclosure; and a pneumatic bistable member that is supplied with air by different first and second compressed air sources and that is suitable for supplying the pneumatic control unit and the depressurizing device with air coming from the first or the second compressed air source as a function of the operating speed of the turbine engine.

Abstract: A gas turbine engine includes an engine core including: a compressor system including first, lower pressure compressor, and second, higher pressure compressor; and inner and outer core casings that define a core working gas flow path (A) therebetween, which has an outer radius that defines a gas path radius. The outer core casing includes a first flange connection that: has a first flange radius, is arranged to allow separation of the outer core casing at an axial position thereof, and is the first flange connection that is downstream of an axial position defined by the axial midpoint between the mid-span axial location on trailing edge of the most downstream aerofoil of first compressor and mid-span axial location on leading edge of the most upstream aerofoil of the second compressor. A gas path ratio of: first ? ? flange ? ? radius gas ? ? path ? ? radius is equal to or greater than 1.10.

Abstract: A control system for a gas turbine engine comprises a case structure, a clearance control ring mounted for movement relative to the case structure, an outer air seal mounted to the clearance control ring and facing a first engine component, and a control and valve assembly that receives flow from a flow input source. The control and valve assembly is configured to direct flow into a first cavity positioned radially between the case structure and the outer air seal, and wherein the control and valve assembly is configured to direct flow into a second cavity positioned downstream of the first cavity to interact with a second engine component. A method of controlling flow between a compressor section and turbine section is also disclosed.

Abstract: A gas turbine combustor assembly includes: a primary combustion chamber in fluid communication with a primary fuel outlet of a primary fuel injector; a torch igniter coupled to the primary combustion chamber, the torch igniter including an auxiliary combustion chamber and an auxiliary fuel injector having an auxiliary fuel outlet in fluid communication with the auxiliary combustion chamber; and a fuel circuit including a first supply flowpath between a fuel inlet and the primary fuel injector, a second supply flowpath between the fuel inlet and the auxiliary fuel injector, and a bypass flowpath between the auxiliary fuel injector and the primary fuel injector.

Abstract: A clearance control system for a gas turbine engine comprises at least one case support associated with an engine case defining an engine center axis. A clearance control ring is positioned adjacent the at least one case support to form an internal cavity between the engine case and the clearance control ring. The clearance control ring includes a first mount feature. An outer air seal has a second mount feature cooperating with the first mount feature such that the clearance control ring can move independently of the engine case in response to changes in temperature. An injection source inject flow into the internal cavity to control a temperature of the clearance control ring to allow the outer air seal to move in a desired direction to maintain a desired clearance between the outer air seal and an engine component. A gas turbine engine and a method of controlling tip clearance in a gas turbine engine are also disclosed.

Abstract: A hybrid-electric propulsion system for an aircraft includes a propulsor and a turbomachine. The turbomachine includes a high pressure turbine drivingly coupled to a high pressure compressor through a high pressure spool. The hybrid electric propulsion system further includes an electrical system including a first electric machine, a second electric machine, and an electric energy storage unit electrically connectable to the first and second electric machines. The first electric machine is coupled to the high pressure spool of the turbomachine and the second electric machine is coupled to the propulsor for driving the propulsor to provide a propulsive benefit for the aircraft. The hybrid electric propulsion system also includes a controller configured to provide electrical power from an electric power source to the first electric machine to drive the first electric machine to start, or assist with starting, the turbomachine.

Abstract: A gas turbine engine (10) for an aircraft comprises an engine core (11) comprising: a compressor system comprising a first, lower pressure, compressor (14), and a second, higher pressure, compressor (15); and an outer core casing (70) surrounding the compressor system. The gas turbine engine further comprises a fan (23) located upstream of the engine core (11), the fan comprising a plurality of fan blades.

Abstract: A fuel system for an aircraft is provided having an improved fluid circuit and method of operation. Un-burnt fuel is directed via a return loop towards a fuel tank reservoir. A turbine is located in the return loop and upstream from the fuel tank. The pressurized un-burnt fuel energizes the turbine and the fuel passes to the fuel tank. The turbine is harnessed to a generator for providing a power.

Abstract: An aircraft engine for use in a low-bypass turbofan application has a high pressure turbine having a blade and an engine casing disposed about the blade. A shield is disposed around the casing adjacent to the blade to create an area between the shield and the casing. A gate selectively controls entry of cooling air into the area and may be closed if the engine is maneuvering and may be open if cruising.

Abstract: In a gas turbine engine that includes a compressor and a combustor, wherein the combustor includes a primary fuel injector within a fuel nozzle and a secondary fuel injector that is upstream of the fuel nozzle and configured to inject fuel into a flow annulus of the combustor, a method for detecting a flame holding condition about a fuel injector. The method may include the steps of: detecting an upstream pressure upstream of the secondary fuel injector; detecting a downstream pressure downstream of the secondary fuel injector; determining a measured pressure difference between the upstream pressure and the downstream pressure; and comparing the measured pressure difference to an expected pressure difference.

Abstract: Variable rate ignition method and system that take advantage of knowledge and analysis of environmental conditions and/or operational conditions. A variable ignition rate for igniting the engine permits an optimal use of the igniters and thereby prolongs their life as well as its associated maintenance schedule. Operating costs and durability are also enhanced. Furthermore, flexibility is enhanced since any changes to the method of determining the best spark rate can be made through update in the software of the engine controller instead of change in the hardware (e.g., the exciter).

Abstract: The present invention provides a gas turbine combustion system capable of minimizing unburned content of a gas fuel under all load conditions from partial load to rated load. A gas turbine combustion system includes: a plurality of gas fuel burners 32, 33; an IGV 9 that adjusts a flow rate of air to be mixed with a gas fuel; and a control system 500 that temporarily reduces an air flow rate from a reference flow rate to a set flow rate by outputting a signal to the IGV 9 when a combustion mode is switched from a partial combustion mode in which the gas fuel is burned with part of the gas fuel burners 32, 33 to a full combustion mode in which the gas fuel is burned with all of the gas fuel burners 32, 33.

Abstract: A gas turbine engine includes a first spool, a first gear system connected to and driven by the first spool, a second spool, and a second gear system connected to and driven by the second spool. A first starter-generator has a first shaft with a switchable coupling connected to the first shaft. The switchable coupling selectively couples the first starter-generator to the first gear system when the switchable coupling is in a first position and selectively couples the first starter-generator to the second gear system when the switchable coupling is in a second position.

Abstract: In a testing overspeed protection system: a) on receiving an order to start a turbomachine, an electronic regulation system (ERS) of the turbomachine sends an order to a control circuit of a fuel cutoff member to close the fuel cutoff member or to keep it in the closed position; b) the closed state of the FCM is verified on the basis of information transmitted to the ERS and representative of the position of the FCM; c) if the result of the verification in b) is positive, the ERS sends an order to the FCM control circuit to authorize opening of the FCM and enable the starting procedure to continue; and d) if the result of the verification in b) is negative, the ERS issues fault information concerning the overspeed protection system.

Abstract: A starting process for a gas turbine (28) that holds the turbine speed of rotation at an ignition speed setting during an ignition window (58), with the ignition speed setting being based on ambient air conditions to achieve a specified combustor air mass flow rate (52). A fuel flow rate may be set based on the fuel type and temperature to achieve a particular air/fuel ratio in a combustor. The fuel flow rate may be adjusted during the ignition window and thereafter based on a combustor inlet air temperature (46). Completion of ignition may be determined by a reduction (68) in a blade path temperature spread (66). After ignition, fuel flow is increased to accelerate the turbine to full speed. At any point, the fuel flow may be reduced, or its increase may be slowed, to avoid exceeding a temperature limit in the turbine.

Abstract: A start-up system including a control system controlling a partial opening of an air intake valve of a start-up turbine during a first phase of the start-up.

Abstract: The start-up system comprises a control loop, which regulates in real time the opening of a valve of an air feed of a start-up turbine based on the current measured speed of rotation of a rotor of the turbomachine and a predetermined speed value, said start-up turbine being capable of turning the rotor of the turbomachine for the purpose of the start-up.

Abstract: A method for controlling a flow of fuel to a starting gas turbine engine includes controlling the flow of fuel to the engine by controlling fuel pressure to the engine, and modulating the flow of fuel to the engine if engine exhaust gas temperature approaches a given exhaust gas temperature to lower the engine exhaust gas temperature below the given exhaust gas temperature.

Abstract: A cooling system for turbine starter lubricant includes one or more outflow transfer passages (54) extending from the turbine starter (10) to a secondary component (40). At least one heat exchange passage (56) affixed at a first end to an end of an outflow transfer passage (54) of the one or more outflow transfer passages (54), is located in the secondary component (40) having a lower interior temperature than the turbine starter (10). One or more return transfer passages (60) are affixed to a second end of the at least one heat exchange passage (56) and extend from the secondary component (40) to the turbine starter (10). Flowing a volume of starter lubricant (42) through the one or more outflow transfer passages (54), the at least one heat exchange passage (56), and the one or more return transfer passages (60) removes thermal energy from the volume of starter lubricant (42) and returns the volume of starter lubricant (42) to the turbine starter (10).

Abstract: One embodiment of the present disclosure is a unique gas turbine engine. Another embodiment of the present disclosure is a unique machine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engines and electrical systems.

Abstract: A turbine engine is disclosed herein. The turbine engine includes a starter/generator operable to deliver rotational power in a first mode of operation and to generate electrical power in a second mode of operation. The turbine engine also includes an accessory gear box mechanically coupled to the starter/generator. The turbine engine also includes a shaft mechanically coupled to the accessory gear box such that the accessory gear box is operably disposed between the shaft and the starter/generator. The turbine engine also includes a clutch operably disposed between the accessory gear box and the starter generator. The clutch is operable to slip in and out of full engagement in response to a first predetermined level of torque between the starter/generator and the accessory gear box.

Abstract: The method and apparatus for in-flight relighting of a turbofan engine involve in one aspect selectively controlling an accessory drag load on one or more windmilling rotors to permit control of the windmill speed to an optimum value for relight conditions.

Abstract: A method of starting a gas turbine engine includes a primary warming step of warming a heat exchanger (6) by means of a compressed gas (G1) while with the use of an inverter motor (IM) the rotation speed of the engine is maintained at a partial rotation speed, a secondary warming step of warming the heat exchanger (6) by activating a main combustor (2) to gradually increase the temperature of an exhaust gas (G3) while with the use of the inverter motor (IM) the rotation speed is maintained at the partial rotation speed, and a speed increasing step of increasing the rotation speed to the rated rotation speed with the use of the inverter motor (IM) while the fuel burning amount of the main combustor (2) is increased.

Abstract: A starting method for a gas turbine engine includes a primary warming step of warming up the gas turbine engine while a constant primary warm-up rotation speed is maintained by an inverter motor and a secondary warming step of warming up the gas turbine engine while a constant secondary warm-up rotation speed is maintained by further increasing the speed of the inverter motor. The primary warming step terminates when an electric power required by the inverter motor attains a predetermined preset electric power value. The preset electric power value is so chosen as to decrease as the intake air temperature is low.

Abstract: A method of delivering a purge flow through a gas turbomachine includes generating a purge flow, guiding the purge flow through at least one of a combustor assembly and a turbine portion of the gas turbomachine, determining a cumulative purge volume passing through the one of the combustor assembly and the turbine portion of the gas turbomachine to determine a predetermined purge volume, and discontinuing the purge flow once the predetermined purge volume has passed through the one of the combustor assembly and the turbine portion of the gas turbomachine.

Abstract: An air conditioning system in an aircraft is provided. The system comprises at least one air cycle air-conditioning pack with a compressor comprising a bleed air outlet and with a compressed-air line connected to the bleed air connection, which compressed-air line is connectable to a starter turbine for a main engine. With the use of air from a compressor of an air conditioning pack it is not necessary to switch off the air conditioning pack; bleed air removal from the auxiliary power units becomes obsolete; and, since there is no unnecessary discharge of compressed air from a bleed air system, noise pollution on the ground is reduced.

Abstract: There is described a method for and system for starting at least one engine from a twin engine installation.

Abstract: A system and method for startup control of a gas turbine is disclosed. The system and method includes defining a target startup time for the startup of the gas turbine and determining a remaining time to achieve the target startup time. The system and method includes monitoring at least one parameter associated with the startup and determining a first operating point for the parameter. The system and method adjusts the first operating point for the parameter to a second operating point based at least in part on the remaining time for the startup. The system and method controls an effector based on the second operating point for the parameter.

Abstract: Starter control valve failure prediction machines, systems, computer readable media, program products, and computer implemented methods to predict and trend starter control valve failures in gas turbine engines using a starter control valve health prognostic and to make predictions of starter control valve failures, are provided.

Abstract: A thermal stress reduction method includes ramping an electric power generator to start an aircraft engine, for a time period associated with the aircraft engine start sequence toggling a three-level inverter switch array to a three-level pulse width modulation mode, determining if a first time interval in the three-level pulse width modulation mode exceeded a predetermined three-level pulse width modulation mode interval, in response to the first time interval exceeding the three-level pulse width modulation mode interval, toggling the three-level inverter switch array to a two-level pulse width modulation mode, determining if a second time interval in the two-level pulse width modulation mode exceeded a predetermined two-level pulse width modulation mode interval and in response to the second time interval exceeding the two-level pulse width modulation mode interval, toggling the three-level inverter switch array to the three-level pulse width modulation mode.

Abstract: Method for conditioning a power supply for starting a jet engine having an electrical starting system with an auxiliary power unit in parallel with a DC power supply.

Abstract: A procedure for igniting a combustion chamber of a turbine engine, the chamber being fed with fuel by injectors and including an igniter mechanism igniting the fuel injected into the chamber. The procedure includes an initial stage during which fuel is injected into the chamber at a constant rate while simultaneously exciting the igniter mechanism, and in event of non-ignition of the chamber at an end of the initial stage, a second stage during which a rate at which fuel is injected is increased rapidly by 20% to 30%.

Abstract: The invention relates to a method for starting a gas and steam turbine system which comprises a gas turbine system which comprises at least one gas turbine, in addition to at least one steam turbine system which comprises at least one steam turbine and at least one steam system. Heat produced by the working fluid and which is released in the gas turbine is guided to the steam system in order to produce steam which drives the steam turbine. According to the invention, during starting, the gas turbine is started prior to the steam turbine and the steam turbine is started in the presence of the first steam in the system and is impinged upon by said steam.

Abstract: A method and device for igniting a turbomachine combustion chamber including alternately: an intake phase of a fluid into a chamber through an intake port, during which a piston compresses an elastic mechanism under pressure of the fluid such that the elastic mechanism applies onto a piezoelectric element a force sufficient for the piezoelectric element to induce between the electrodes an electric voltage enabling an electric arc to be generated, until the piston reaches a predetermined position for closing a valve for sealing the intake port; and an exhaust phase of the fluid, during which the elastic mechanism pushes back the piston to induce a fluid ejection out of the chamber through an exhaust port, and the valve is open.

Abstract: A nacelle for incorporation into a gas turbine engine has an inner wall defining a bypass duct, and an outer wall. At least one drive shaft extends through the inner wall. The at least one drive shaft is connected to a gas turbine engine receiving the nacelle. The at least one drive shaft is connected to drive at least two accessory gear boxes, with the at least two accessory gear boxes being received between the inner and outer walls of the nacelle. A gas turbine engine is also disclosed.

Abstract: Gas turbine engines systems and methods involving oil flow management are provided. In this regard, a oil pressure analysis system for a gas turbine engine is operative to: receive information corresponding to measured oil pressure and rotational speed during a start up of the engine; correlate the information into data sets, each of the data sets containing a measured oil pressure and a corresponding rotational speed; and determine whether the oil flow valve is functioning properly based on the information contained in the data sets.

Abstract: An electrical machine is embedded into the compressor assembly of a gas turbine engine. An electrical system interface module distributes electrical current to and from the embedded electrical machine for starting the gas turbine engine and for operating accessory components. Accordingly, the gas turbine engine and accessory components can be started and operated without a power-takeoff shaftline and without an external accessory gearbox.

Abstract: A turboprop propulsion unit for an aircraft comprises a propeller 22 which is driven by a core engine by means of a propeller turbine 26 which drives the propeller 22 through a shaft 28 and a propeller gearbox 24. Restarting of the engine in flight is achieved by windmilling of the propeller 22, which drives a propeller gearbox lubricant pump 30. A diverter valve 40 causes lubricant delivered by the propeller gearbox lubricant pump 30 to be supplied to a turbomachinery lubricant pump 18 along a restart conduit 44, so as to drive the turbomachinery lubricant pump 18 as a motor. Torque generated by the turbomachinery lubricant pump 18 is transferred through an accessory gearbox 12 to a spool 4, 6, 8 of the core engine 2 and to a fuel pump 16. Control of the pitch of blades 36 of the propeller 22 enables the windmilling propeller 22 to achieve a desired speed of the spool 4, 6, 8 and output of the fuel pump 16 sufficient to restart the engine 2, even at low air speeds.

Abstract: Systems and methods for generating a predictable load upon a completion of a start sequence of a gas turbine are provided. According to one embodiment, a system may include a controller to control the gas turbine and a processor communicatively coupled to the controller. The processor may be configured to receive a start duration and a desired final load, and to calculate a target load rate to substantially reach the desired final load within the start duration based on the start duration and the desired final load. Measurements of a present load may be periodically received from a measuring device and used to periodically recalculate the target load rate. A present load rate may be periodically adjusted by the controller based on the recalculation.

Abstract: A method of starting a turbomachine, performed by an electronic unit, the turbomachine including a gas turbine engine including at least one rotor and a starter to drive the rotor in rotation, the method including: receiving an order to start the turbomachine, and executing in response to receiving the order to start: a primary acceleration during which the starter is operated to increase speed of rotation of the rotor; a thermal homogenization during which the starter is operated to keep the speed of rotation of the rotor constant or to decrease it until a predetermined condition is satisfied; after the predetermined condition is true, a secondary acceleration in which the starter is operated to increase the speed of rotation of the rotor; and an ignition in which ignition of the engine is ordered.

Abstract: A method for monitoring the change in state of a valve in a start up circuit of a turbo-engine following a command to change the state of the valve includes measuring the air pressure under a fan cowl of the turbo-engine before the change state command, measuring the air pressure under the fan cowl after the change state command, comparing the measured values of the air pressure, and determining whether or not the valve has actually changed state. An aircraft turbo-engine includes a unit that monitors the change in the valve using such a method.

Abstract: A gas turbine engine has a compressor section, a low spool, and a fan. The fan delivers air into the compressor section and into a bypass duct having a variable area nozzle. The compressor section compresses air and delivers it into a combustion section. The combustion section mixes air with fuel, igniting the fuel, and driving the products of the combustion across a turbine. The turbine drives the low spool. A control for the gas turbine engine is programmed to position the nozzle at startup of the engine to increase airflow across the fan. A variable inlet guide vane is positioned upstream of the compressor section. The control also positions the variable inlet guide vane at start-up to increase air flow across the compressor section.

Abstract: A method of aligning flanges on two components to align and transfer torque from one component to the other uses a plurality of scallop regions on the periphery of a flange on one component; and a plurality of raised regions on the periphery of a flange on the other component, the raised regions being sized and shaped to engage the scallop regions on the flange when axially aligned to transfer torque there between

Abstract: Embodiments of the present invention employ a closed loop controls philosophy, which actively controls the starting means of a powerplant machine, throughout the start-up process. Here, the present invention may provide a method for adjusting a nominal operating schedule of the starting means, which may have the form of a Load Commutated Inverter (LCI). Embodiments of the method may adjust the nominal operating schedule based, in part, on an operating parameter, which is associated with the gas turbine 100. The operating parameter may include, but is not limited to: a rotor speed, a desired start-up time, or the like. Here, the control system may receive data on the operating parameter associated with the gas turbine.

Abstract: A gas turbine engine has a compressor section, a low spool, and a fan. The fan delivers air into the compressor section and into a bypass duct having a variable area nozzle. The compressor section compresses air and delivers it into a combustion section. The combustion section mixes air with fuel, igniting the fuel, and driving the products of the combustion across a turbine. The turbine drives the low spool. A control for the gas turbine engine is programmed to position the nozzle at startup of the engine to increase airflow across the fan. A variable inlet guide vane is positioned upstream of the compressor section. The control also positions the variable inlet guide vane at start-up to increase air flow across the compressor section.

Abstract: A gas turbine combustor burns a fuel mixture at a high combustion efficiency and a low NOx emission, is simple in construction and exercises improved ignition performance, and an ignition method can efficiently igniting a fuel mixture in the gas turbine combustor. A gas turbine combustor provided with fuel nozzles each having a pilot fuel injection nozzle and a main fuel injection nozzle, and fuel nozzles each having a pilot fuel injection nozzle and a main fuel injection nozzle. The fuel nozzle disposed close to an igniter is provided with a local fuel injection port through which fuel is jetted out from a predetermined position in an air passage in the main fuel injection nozzle to create a combustible fuel mixture zone in the vicinity of the igniter at least while the igniter is in an ignition operation.