Abstract: Example variable bleed valve assemblies for a gas turbine engine are disclosed herein. An example apparatus disclosed herein includes a variable bleed valve port extending radially outward from a main flow path of a gas turbine engine, a door positioned at an exit of the variable bleed valve port, the door including perforations, a damper coupled to the door, the damper including a resonator adjacent to the perforations of the door, the resonator defining an internal volume based on a resonant frequency of the variable bleed valve port.

Abstract: A turbomachine comprises a high-pressure rotor shaft defining an outer surface and including a rotor seal disposed along the outer surface. A compressor discharge plenum extends annularly around the outer surface of the high-pressure rotor shaft and is at least partially formed from an inner casing assembly defining a first airflow opening. The rotor seal is configured to form a first seal against a first surface of the inner casing assembly. A pressure seal disk is coupled to the high-pressure rotor shaft. The pressure seal disk is configured to form a second seal against a second surface of the inner casing assembly. The inner casing assembly, the high-pressure rotor shaft, the rotor seal, and the pressure seal disk form a pressure chamber therebetween. The pressure chamber is in fluid communication with the compressor discharge plenum via the first airflow opening.

Abstract: A turbine engine having an engine core having a compression section, combustion section, a turbine section, and an engine drive shaft. The turbine engine includes an air turbine starter having a housing defining an air flow passage. The air turbine starter can operate in a start-up mode and a shut-down mode. The turbine engine further includes a gearbox and a drive unit.

Abstract: A coupling assembly for a turbine engine. The coupling assembly includes a cold side component, a hot side component, and a fastening mechanism. The cold side component and the hot side component together at least partially form a combustion chamber. The fastening mechanism couples the hot side component to the cold side component. The fastening mechanism includes a stud disposed through the cold side component and a cap positioned on the stud. The cap defines a hollow interior and includes one or more first cap cooling holes. The one or more first cap cooling holes operably direct cooling air into the hollow interior such that the hollow interior provides a cushion of air between the combustion chamber and the stud.

Abstract: A self-cleaning conduit for a hydrocarbon fluid. The conduit includes a tube and a mesh. The tube has an interior surface defining a flow passage for the hydrocarbon fluid. The mesh is positioned within the flow passage to abut the interior surface and movable along the interior surface to break-up deposits on the interior surface. The mesh is characterized by a mesh activation parameter (MAP) from one ten thousandths to six tenths.

Abstract: A turbine engine having an engine core having a compression section, combustion section, a turbine section, and an engine drive shaft. The turbine engine includes an air turbine starter having a housing defining an air flow passage. The air turbine starter can operate in a start-up mode and a shut-down mode. The turbine engine further includes a gearbox and a drive unit.

Abstract: A lubrication system for a turbine engine having one or more rotating components. The lubrication system includes a primary reservoir that stores a lubricant therein. A primary lubrication system supplies the lubricant from the primary reservoir to the one or more rotating components during normal operation of the turbine engine. An auxiliary lubrication system includes an auxiliary reservoir in fluid communication with the primary reservoir and the one or more rotating components. The auxiliary reservoir receives the lubricant from the primary reservoir and is positioned at substantially a six o'clock position of the turbine engine. The auxiliary lubrication system supplies the lubricant from the auxiliary reservoir to the one or more rotating components based on at least one of a pressure of the lubricant in the primary lubrication system, a pressure of fuel in the turbine engine, or a pressure of hydraulics of the turbine engine.

Abstract: Bearing assemblies for a turbomachine include a first race statically coupled to a fixed engine housing, a second race coupled to a rotating shaft, a bearing cage disposed between the first race and the second race, and at least one bearing element disposed in the bearing cage. The bearing cage can include inlet channels to allow air to flow into the bearing cage and outlet channels that allow the air and lubricant mixture in the bearing cage to vent into adjacent compartments of the turbomachine. During operation, the inlet channels actively direct an airflow into the bearing cage. In the bearing cage, the air mixes with lubricant, and the air and lubricant mixture is expelled from the bearing cage through the outlet channels, thereby reducing dwell time of lubricant in the bearing assembly.

Abstract: A gas turbine engine includes a fan section having a plurality of fan blades, the fan section configured to generate an airflow through the gas turbine engine, an airflow passage having a core passage and a bypass passage separate from the core passage, a low-speed shaft coupled to and configured to rotate the plurality of fan blades, and a sensor assembly coupled to the gas turbine engine and configured to detect torsional vibration in the low-speed shaft. The sensor assembly includes a plurality of dynamic pressure sensors in the airflow passage. The plurality of dynamic pressure sensors detect a dynamic pressure of the airflow passage that is indicative of the torsional vibration in the low-speed shaft. A damping system is configured to dampen the torsional vibration in the low-speed shaft based on a correlation of a measured torsional vibration and an experimental torsional vibration.

Abstract: A seal assembly for a rotary machine. The seal assembly includes a rotor and a stator. The rotor is rotatable about a rotational axis and has a rotor seal face. The stator has a stator seal face. The stator seal face is positioned opposite the rotor seal face and faces the rotor seal face with a gap therebetween. A portion of one of the rotor and the stator is formed of (i) a shape memory alloy or (ii) a first metal and a second metal with the second metal having a coefficient of thermal expansion different from the first metal. The seal assembly is characterized by a seal clearance compliance ratio (SCCR) from 20% to 90%.

Abstract: Separators for use with gas turbine engines are disclosed herein. An example cabin bleed system disclosed herein includes a bleed line coupled to a gas turbine engine, a separator defining a cavity fluidly coupled to the bleed line, the separator including a first ring including a first opening fluidly coupled to the cavity. a second ring surrounding the first ring, the second ring including a second opening fluidly coupled to a cabin of an aircraft, and a filter disposed in a fluid pathway extending between the first opening and the second opening.

Abstract: Systems, apparatus, articles of manufacture, and methods are disclosed to improve fan operability control using smart materials. An engine comprising an engine surface in an airflow path, a sensor positioned on the engine surface, and a smart-material-based feature positioned on the engine surface, the smart-material-based feature triggered to modify the airflow path when the sensor outputs an indication of a detected deviation from a reference value of an operating parameter of the engine.

Abstract: A mounting assembly for a gearbox assembly of a gas turbine engine includes at least one mounting member configured to mount a gear of the gearbox assembly to a component of the gas turbine engine, the at least one mounting member characterized by a lateral impedance parameter, a bending impedance parameter, and a torsional impedance parameter. A gas turbine engine includes the mounting assembly. The at least one mounting member may be a flex mount, a fan frame, or a flex coupling. The gas turbine engine includes an electric power system including at least one electric machine. The electric power system includes a plurality of power converters and a plurality of power distribution management units. At least two of the plurality of power converters or the plurality of power distribution management units are integrated together in a single housing.

Abstract: Disclosed herein are example variable flowpath casings for blade tip clearance control. An example casing for a turbine engine includes a first annular substrate extending along an axial direction; a second annular substrate positioned radially inward relative to the first annular substrate, the second annular substrate movably coupled to the first annular substrate; and an actuator coupled to the second annular substrate such that a force applied by the actuator moves the second annular substrate relative to the first annular substrate to adjust a tip clearance.

Abstract: Example bearing lubrication system and methods of operating the same are disclosed herein. An example closed loop system to provide a lubricant to a fluid pump includes a lubrication flow network disposed within the fluid pump; a sensor fluidly coupled to the fluid pump to measure a condition of a fluid that is to enter the lubrication flow network; a first transport bus fluidly coupled to the lubrication flow network, the first transport bus to transport an inert gas; a controller to actuate a valve fluidly coupled to the first transport bus, the controller to transmit signals to the valve based on the condition of the fluid to cause the valve to open or close; and a separator fluidly coupled between an outlet of the fluid pump and the first transport bus, the separator to separate the fluid and the inert gas.

Abstract: Seals for a gas turbine engine are disclosed herein. An example sealing apparatus for a gas turbine engine includes a first end having a first contact surface to contact a first component of a rotating machine, a second end having a second contact surface to contact a second component of the rotating machine, the second component positioned in proximity to the first component such that a cavity is formed therebetween, the apparatus dividing the cavity into a first cavity portion and a second cavity portion, and a central portion extending the first end from the second end, the central portion defining a first chamber and a second chamber, the first chamber in fluid communication with the first cavity portion, the second chamber in fluid communication with the second cavity portion, the first chamber is fluidly isolated from the second chamber.

Abstract: This disclosure is directed to seal assemblies for a turbomachine. The seal assemblies include stationary and rotating components and at least one interface between the stationary and rotating components. The seal assembly further includes a self-lubricating lattice element made of carbon or a carbon-based material. The self-lubricating lattice element may have a porous and compressible microstructure capable of retaining a liquid substance. During engine operation, the self-lubricating lattice element can compress and expel some portion of the liquid substance to form a liquid-containing layer between the rotating and stationary components of the seal assembly. Also described herein are self-lubricating wear sleeves for use in other portions of the turbomachine.

Abstract: Disclosed herein are example variable flowpath casings for blade tip clearance control. An example casing for a turbine engine includes an annular substrate extending along an axial direction, the annular substrate including a first surface and a second surface that is radially inward relative to the first surface; an actuator structure coupled to the second surface of the annular substrate; and a smart structure cantilevered from the second surface of the annular substrate, the smart structure including: a support structure, a first region of the support structure coupled to the second surface of the annular substrate, a second region of the support structure coupled to the actuator structure; and a radially inward surface defining a variable surface, the support structure to move the variable surface in a radial direction.

Abstract: A dome-deflector assembly for a combustor of a gas turbine includes a dome portion having a dome-side swirler opening therethrough, and a deflector portion having a deflector-side swirler opening therethrough. The dome portion and the deflector portion are connected together to form a dome-deflector cavity therebetween. The deflector portion includes a first-side surface and a second-side surface, the second-side surface being arranged within the dome-deflector cavity, and the second-side surface including a plurality of stress-relief contours arranged in a pattern about the deflector-side swirler opening.

Abstract: A turbine engine with a compressor section, a combustion section, and a turbine section in serial flow arrangement along an engine centerline. The combustion section includes a primary combustor liner including an inner liner and an outer liner. A dome wall and a primary dome inlet are located in the dome wall. The outer liner defines at least one opening downstream from the primary dome inlet. A primary combustion chamber and a set of secondary combustors are fluidly coupled to the primary combustion chamber at the at least one opening.