Abstract: A gas turbine engine includes a plural spool assembly including a first spool and a second spool. The engine also includes an accessory configured to change between a motor mode and a generator mode and a transmission configured to transmit mechanical power between the accessory and at least one of the first spool and the second spool. The transmission, when the accessory is in the generator mode, is configured to transmit mechanical power from the first spool to the accessory for generating electric power at the accessory. The transmission, when the accessory is in the motor mode, is configured to transmit mechanical power from the accessory to the second spool.

Abstract: A fuel system can include a total flow line configured to receive a total flow and a primary flow line connected to the total flow line. The primary flow line can be in fluid communication with one or more primary fuel nozzles of a nozzle assembly. The fuel system can include a secondary flow line connected to the total flow line in parallel with the primary flow line, the secondary flow line in fluid communication with a plurality of secondary flow nozzles of the nozzle assembly. The fuel system can include a flow split system configured to control a flow split between a primary flow of the primary flow line and a secondary flow of the secondary flow line.

Abstract: A face seal includes a seal carrier defining an axis and having a pilot flange, a seal element disposed at least partially in the seal carrier, and a retaining plate connected to one axial end of the seal carrier. The retaining plate has an axial step disposed circumferentially about the retaining plate. The axial step is interfaced with the pilot flange.

Abstract: The invention relates to an aircraft propulsion system, comprising a main transmission unit (12) and at least two turbojet engines connected to the main transmission unit (12), respectively a first turbojet engine (14a) and a second turbojet engine (14b), each turbojet engine comprising a free turbine (24a, 24b), characterized in that the first turbojet engine (14a) comprises a heat exchanger (30) configured to recover some of the thermal energy from the exhaust gas at the outlet of the free turbine, and in that the propulsion system comprises at least one computer (28a, 28b) configured to control the two turbojet engines and to limit the acceleration and the deceleration of the first turbojet engine (14a) when neither of the turbojet engines is broken down, in order to limit the reactor power transients at the heat exchanger (30).

Abstract: The invention relates to a combustion chamber comprising: a duct (722) with a recess for a spark plug (13) emerging into an inner space of the combustion chamber, and a plug guide mounted on the duct so as to be movable transversely relative to the axis of the duct. The duct is crossed by openings (722b) which, parallel to the axis of the duct, are staggered in a plurality of rows (74a, 74b . . . ) over the height (H) of the duct, with at least some of the openings individually having a diameter of 0.2 to 0.6 mm.

Abstract: A system and method of an airflow control system for a vehicle is described herein. The airflow control system (100) includes an airflow housing (120) defining an airflow passageway (125) extending between a bypass opening (122) and an intake outlet (124). The airflow housing also defines a duct opening (126) positioned between the bypass opening (122) and the intake outlet (124). The intake outlet (124) may be in fluid communication with an engine intake (12) of the vehicle such that air passes from the bypass opening (122) and/or the duct opening (126) to the engine intake (12). The airflow control system (100) also includes a movable duct (160) movably connected to the airflow housing (120) to selectively allow or prevent air passage through the duct opening (126) and into the engine intake (12), and further includes a bypass door (140) movably connected to the airflow housing (120) to selectively allow or prevent air passage through the bypass opening (122) and into the engine intake (12).

Abstract: A gas turbine combustor includes multiple aft frames each having a floating seal that seals a gap between an aft frame and a gas turbine in inner and outer peripheries of the aft frame, and a side seal that seals a gap between the aft frames adjacent to each other in a circumferential direction, and a corner seal that is placed in a gap portion provided between corner portions of the aft frames adjacent to each other in the circumferential direction, seals air leaking from at least the gap portion into the gas turbine side, and is independent of the floating seal and the side seal.

Abstract: To achieve a reduction in waste heat loss of a fuel with improved efficiency in arrangement of a plurality of cavities, or manifold spaces. A multi-stage combustor includes a combustor liner configured to define a combustion chamber therein, a plurality of fuel nozzles configured to inject a fuel, and a manifold configured to distribute the fuel to the plurality of fuel nozzles. The manifold is disposed on a central axis of the combustor liner in a central axis extending direction. The manifold includes a casing and a plurality of partitions inserted in the casing so as to be arranged in a central axis direction of the combustor liner to define a plurality of cavities divided by the partitions. The plurality of cavities are layered in the central axis direction of the combustor liner inside of the casing, and are connected to the corresponding fuel nozzles.

Abstract: A combustor for a turbomachine includes a head end, a liner at least partially defining a hot gas path, and a flow sleeve circumferentially surrounding at least a portion of the liner. The flow sleeve is spaced from the liner to form a cooling flow annulus therebetween. The cooling flow annulus is in direct fluid communication with a high pressure plenum, whereby air from the high pressure plenum flows into the cooling flow annulus and from the cooling flow annulus to the head end. The combustor further includes a first combustion zone and a second combustion zone downstream of the first combustion zone along the hot gas path. A plurality of fuel injectors are in fluid communication with the second combustion zone and are not in direct fluid communication with the high pressure plenum.

Abstract: A method of controlling a gas turbine engine capable of operating in at least a high output power range, a medium-high output power range, a medium-low output power range and a low output power range. The method includes during the medium-high output power range 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 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.

Abstract: A fuel system for a gas turbine engine includes a secondary flow lockout valve. The secondary flow lockout valve includes a valve body having a first end that defines an inlet and a second end. The valve body includes at least one primary outlet bore and at least one secondary outlet bore. The valve body defines a channel in fluid communication with the primary outlet bore. The secondary flow lockout valve includes a cover that cooperates with the second end of the valve body to define a chamber. The chamber is in fluid communication with the channel such that the valve body is movable between at least a first position in which the primary outlet bore is open and a second position in which both the primary outlet bore and the secondary outlet bore are open based on a pressure in the chamber.

Abstract: 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.

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 accessory system for a gas turbine engine having a driveshaft is provided. The accessory system includes a towershaft coupled to the driveshaft and driven by the driveshaft. The accessory system also includes a shaft including a first shaft bevel gear coupled to a towershaft bevel gear. The shaft is rotatable by the towershaft. The accessory system includes a first accessory drive shaft having a first accessory bevel gear driven by the shaft. The accessory system also includes a second accessory drive shaft having a second accessory bevel gear driven by the shaft.

Abstract: Intercooling systems and methods for an aircraft engine are provided. An intercooling system includes: a first inlet configured to receive a first air flow of ambient air into the aircraft engine; a second inlet separate from the first inlet and configured to receive a second air flow of ambient air into the aircraft engine separately from the first air flow of ambient air; and a heat exchanger configured to facilitate heat transfer between at least a portion of the first air flow compressed by a compressor section of the aircraft engine and the second air flow.

Abstract: A combustor adapted for use in a gas turbine engine a combustor shell, a heat shield, and a heat shield retainer. The combustor shell is made from metallic materials and is formed to define an internal cavity. The heat shield is formed from ceramic matrix composite materials and is coupled to the dome panel. The heat shield retainer is configured to retain the heat shield to the combustor shell.

Abstract: An accessory system for a gas turbine engine having a driveshaft is provided. The accessory system includes a towershaft coupled to the driveshaft and driven by the driveshaft. The accessory system also includes a shaft including a first shaft bevel gear coupled to a towershaft bevel gear. The shaft is rotatable by the towershaft. The accessory system includes a first accessory drive shaft having a first accessory bevel gear driven by the shaft. The accessory system also includes a second accessory drive shaft having a second accessory bevel gear driven by the shaft.

Abstract: A nozzle having a forward portion skewed downwards and an aft portion translated downwards provides sufficient clearance between the nozzle and the heat shield structure to prevent contact in the event of large deflections (e.g., as associated with a fan blade Out (FBO) condition). Such large deflections must be accounted for to meet federal aviation regulations and gain airplane CFR 14 Part 25 Certification.

Abstract: A system and method for diagnosing load compressor health state for an auxiliary power unit that includes a power compressor, a combustor, a power turbine, and a load compressor is provided. The auxiliary power unit is operated and bleed air is discharged from the load compressor at a bleed air pressure. Using a pressure sensor, the bleed air pressure discharged from the load compressor is sensed and supplied to a processor. In the processor, power compressor health state is diagnosed based solely on the sensed bleed air pressure.

Abstract: An engine system for an aircraft includes a first gas turbine engine, a second gas turbine engine, and a control system. The control system is configured to operate the first gas turbine engine with an idle fuel burn schedule in a taxi mode of the aircraft and operate the second gas turbine engine with a sub-idle fuel burn schedule in the taxi mode of the aircraft. The sub-idle fuel burn schedule includes a reduction of the idle fuel burn schedule. A fuel flow of the first gas turbine engine and the second gas turbine engine is increased above the idle fuel burn schedule prior to takeoff of the aircraft.