Abstract: Dual bypass gas turbine engines and associated methods are provides. A dual bypass turbofan gas turbine engine includes counter-rotating first and second fans through which ambient air is received and propelled in an aft direction; a first bypass duct receiving first bypass air including a first portion of the propelled air; a second bypass duct receiving second bypass air including a second portion of the propelled air; a core gas path receiving core air including a third portion of the propelled air; a compressor pressurizing the core air; an intercooler facilitating heat removal from the pressurized core air; a combustor in which the pressurized core air is mixed with fuel and ignited to generate a stream of combustion gas; a turbine extracting energy from the combustion gas; and a differential gear train apportioning an input torque received from the turbine between the first fan and the second fan.

Abstract: An aircraft engine, has: a high-pressure spool having a high-pressure turbine drivingly engaged to a high-pressure compressor; and a low-pressure spool having: a first low-pressure turbine downstream of the high-pressure turbine; and a second low-pressure turbine downstream of the first low-pressure turbine, one or more of the first low-pressure turbine and the second low-pressure turbine drivingly engaged to a rotatable load, the first low-pressure turbine and the second low-pressure turbine radially offset from one another relative to a central axis of the aircraft engine.

Abstract: Systems and methods for delivering a buffer fluid to a shaft seal of a gas turbine engine are provided. An exemplary system includes, a buffer fluid source, one or more first conduits providing fluid communication between the buffer fluid source and the shaft seal along a first route, and one or more second conduits providing fluid communication between the buffer fluid source and the shaft seal along a second route different from the first route. A heat exchanger is also disposed along the first route to facilitate heat transfer between buffer fluid in the one or more first conduits and a cooling fluid.

Abstract: An aircraft engine comprises a casing extending circumferentially around a central axis. A support flange is secured to the casing and extends circumferentially around the axis. The support flange has an inner and an outer flange face. A component is drivingly engaged by a shaft of the engine. The component has a connecting section extending around the central axis. The connecting section has a connecting face. The inner flange face is in abutment against the connecting face. A retaining ring extends circumferentially around the central axis. The retaining ring is in abutment against the outer flange face of the support flange. The retaining ring has a coefficient of thermal expansion, which is less than that of the support flange.

Abstract: A tool for installing segments of a coupling having male and female couplers drivingly engaged to one another by the segments, the tool has: a coupler-engaging section engageable to the a female coupler of the couplers for radially supporting the tool relative to the female coupler about a rotation axis of the coupling; and a peripheral wall secured to the coupler-engaging section and extending circumferentially around the rotation axis, a diameter (D2) of the peripheral wall selected to allow insertion of the segments between the female coupler and the peripheral wall, the peripheral wall defining an abutting surface against which radially inner ends of the segments abut during insertion of the segments between the female coupler and the peripheral wall.

Abstract: An engine bi-material joint includes a first flange composed of a first material and defining a first coefficient of thermal expansion, and a second flange composed of a second material and defining a second coefficient of thermal expansion. The second flange is different from the first material. An interface flange is engaged with the first flange and with the second flange. The interface flange defines a third coefficient of thermal expansion being equal to or less than the first coefficient of thermal expansion of the first flange. The third coefficient of thermal expansion is less than the second coefficient of thermal expansion of the second flange. The first coefficient of thermal expansion of the first flange is less than the second coefficient of thermal expansion of the second flange.

Abstract: A coupling has: a first coupler rotatable about an axis and defining first connections distributed about the axis; a second coupler defining second connections distributed about the axis, the second connections offset from the first connections; and segments distributed about the axis and extending radially from the first connections to the second connections, a segment of the segments having a first end engaging a first connection of the first connections and a second end engaging a second connection of the second connections, the first end circumferentially offset from the second end, a face of the segment abutting against a face of the first coupler when the segment is inserted into the first connection in a first orientation such that a penetration depth of the segment into the first connection in the first orientation is less than the penetration depth in a second orientation opposite the first orientation.

Abstract: The torque transfer assembly can include a sleeve having an elongated internal opening, a shaft having an elongated body extending in the internal opening of the sleeve, a first coupler at a first end of the elongated body coupled to a gas turbine engine rotor, and a second coupler at a second end of the elongated body coupled to a generator, the second coupler opposite the first coupler relative to a length of the elongated body, the shaft being made of a metal, and a bushing extending around the elongated body of the shaft, trapped between the shaft and the sleeve, the bushing made of plastic, the bushing having a coefficient of thermal expansion greater than a coefficient of thermal expansion of the sleeve.

Abstract: Systems and methods for delivering a buffer fluid to a shaft seal of a gas turbine engine are provided. An exemplary system includes, a buffer fluid source, one or more first conduits providing fluid communication between the buffer fluid source and the shaft seal along a first route, and one or more second conduits providing fluid communication between the buffer fluid source and the shaft seal along a second route different from the first route. A heat exchanger is also disposed along the first route to facilitate heat transfer between buffer fluid in the one or more first conduits and a cooling fluid.

Abstract: An inertial particle separator (IPS) for a gas turbine engine, has: inner and outer walls extending about a central axis, an inlet defined between the inner and outer walls and oriented axially; swirling vanes extending at least radially between the inner and outer walls and circumferentially distributed around the central axis, the swirling vanes configured for inducing a circumferential component in an airflow flowing between the swirling vanes; a plenum between the inner and outer walls downstream of the swirling vanes, the plenum circumferentially extending about the central axis, the outer wall converging toward the central axis in a direction of the airflow; and a splitter radially between the inner and outer walls downstream of the plenum and circumferentially extending around the central axis, a particle outlet radially between the splitter and the outer wall, an air outlet radially between the inner wall and the splitter.

Abstract: An inertial particle separator (IPS) for a gas turbine engine, has: a plenum circumferentially extending about a central axis and defined between an outer wall and an inner wall, the plenum having an inlet facing a circumferential direction relative to the central axis, a radius of the outer wall decreasing in an axial direction relative to the central axis between the inlet and an annular splitter extending circumferentially around the central axis and located downstream of the inlet radially between the outer wall and the inner wall, a particle outlet including an annulus radially between the outer wall and the splitter, an air outlet fluidly connectable to a compressor of the gas turbine engine and defined radially between the splitter and the inner wall.

Abstract: A method of manufacturing a bearing support structure of a gas turbine engine, includes: obtaining a bearing support and a casing assembly, the casing assembly having first and second casings extending around a central axis and connected together via struts, the bearing support securable to the first casing at attachment points; selecting a distance between the attachment points of the bearing support and the struts as a function of a required stiffness of the bearing support structure; and adjusting a position of the bearing support relative to the casing assembly until the attachment points are distanced from the struts by the selected distance and joining the bearing support to the casing assembly at the attachment points.

Abstract: The gas turbine engine for an aircraft includes at least a low pressure spool with a low pressure turbine shaft operatively connected to at least one turbine, the low pressure turbine shaft rotatable about an engine axis, and a low pressure compressor operatively connected to a low pressure compressor shaft that is independently rotatable relative to the low pressure turbine shaft. A differential gearbox has an input operatively connected to the low pressure turbine shaft, a first output and a second output, the first output of the differential gearbox operatively connected to the low pressure compressor shaft and the second output of the differential gearbox operatively connected to an output shaft of the gas turbine engine. The differential gearbox permits the output shaft, the low pressure compressor shaft and the low pressure turbine shaft to rotate at different speeds.

Abstract: A fan blade anti-icing system comprises a fan hub and a fan blade extending radially outwardly from the fan hub. The fan blade has a base and an airfoil extending radially outwardly from the fan base. The airfoil having a leading edge, a trailing edge, a convex side surface between the leading and trailing edge and a concave side surface between the leading and trailing edge. The fan blade further has a radial passage extending from a blade air inlet in the blade base in communication with a source of heated air, and a rearwardly directed passage in communication with the radial passage and having a blade air outlet forward of the trailing edge and oriented tangentially to the convex side surface or concave side surface of the airfoil.

Abstract: The gas turbine engine includes a combustion section including an annular swirl combustor having a combustor inlet, and a compressor section including a centrifugal compressor with an impeller, the impeller compressing and swirling an airflow and discharging the compressed and swirled airflow from the impeller outlet into the combustor inlet. The turbine section includes a radial turbine having a turbine fuel inlet and a turbine fuel outlet, the radial turbine receiving a flow of fuel at the turbine fuel inlet and discharging the flow of fuel from the turbine fuel outlet of the radial turbine into the combustor inlet.

Abstract: A method of heating a fan blade of a gas turbine engine for anti-icing includes emitting jets of heated air from a radial fin disposed upstream from a radially inward portion of a fan blade airfoil, the jets of heated air being directed by outlet orifices in a downstream direction substantially parallel to a flow of incoming air over the fan blade airfoil.

Abstract: Systems and methods for conditioning a fluid using bleed air from a bypass duct of a turbofan engine are disclosed. In one embodiment, such system comprises a heat exchanger configured to facilitate heat transfer between a flow of bleed air from the bypass duct of the turbofan engine and the fluid, and a fluid-driven fluid propeller configured to drive the bleed air through the heat exchanger.

Abstract: Systems and methods for conditioning a fluid using bleed air from a bypass duct of a turbofan engine are disclosed. The system comprises a heat exchanger configured to facilitate heat transfer between a flow of bleed air from the bypass duct of the turbofan engine and the fluid, and a fluid propeller configured to drive the bleed air through the heat exchanger. The fluid propeller is disposed downstream of the heat exchanger.

Abstract: The aircraft engine can have an air-oil separator having an air-oil mixture inlet, an oil outlet, an air outlet, and a pressure relief path provided fluidly in parallel with the air-oil separator, between the air-oil mixture inlet and the air outlet, the pressure relief path can have a pressure relief valve for evacuating air-oil mixture to the exhaust duct in the event of excess pressure in the auxiliary gearbox.

Abstract: A system for controlling gas turbine engine rotor blades tip clearance is described. A rotor is mounted to an engine shaft, supported by a thrust bearing, for rotation within a gas path shroud circumscribing blades of the rotor, the gas path shroud having a non-cylindrical shape in the vicinity of the rotor blades. A rotary actuator is associated with the thrust bearing and configured for axial translation of the thrust bearing, to thereby axially translate the engine shaft and the rotor blades relative to the gas path shroud. This translation is configured to vary the blade tip clearance of the rotor.