Abstract: There are described methods and systems for synchronizing at least two generators for an engine. A first generator is mechanically coupled to the engine. A power source is connected in parallel to the first generator and to a second generator, the second generator mechanically uncoupled from the engine, the power source connected across a same respective phase of a stator in the first generator and the second generator. Power from the power source is applied to the first generator and the second generator to align a respective rotor to the respective phase in each generator and cause the first generator and the second generator to be in-phase. The second generator is then mechanically coupled to the engine.

Abstract: A heat management system of a gas turbine engine for cooling oil and heating fuel, includes an oil circuit having parallel connected first and second branches. The first branch includes a fuel/oil heat exchanger and a first fixed restrictor in series and the second branch includes an air cooled oil cooler and a second fixed restrictor. The first and second fixed restrictors limit respective oil flows through the first and second branch differently, in response to viscosity changes of the oil caused by temperature changes of the oil during engine operation to modify oil distribution between the first and second branches.

Abstract: An anti-icing system for a gas turbine engine comprises a closed circuit containing a change-phase fluid, at least one heating component for boiling the change-phase fluid, the anti-icing system configured so that the change-phase fluid partially vaporizes to a vapour state when boiled by the at least one heating component. The closed circuit has an anti-icing cavity adapted to be in heat exchange with an anti-icing surface of the gas turbine engine for the change-phase fluid to release heat to the anti-icing surface and condense. A feed conduit(s) has an outlet end in fluid communication with the anti-icing cavity to feed the change-phase fluid in vapour state from heating by the at least one heating component to the anti-icing cavity, and at least one return conduit having an outlet end in fluid communication with the anti-icing cavity to direct condensed change-phase fluid from the anti-icing cavity to the at least one heating component.

Abstract: There are described methods and systems for synchronizing at least two generators for an engine. A first generator is mechanically coupled to the engine. A power source is connected in parallel to the first generator and to a second generator, the second generator mechanically uncoupled from the engine, the power source connected across a same respective phase of a stator in the first generator and the second generator. Power from the power source is applied to the first generator and the second generator to align a respective rotor to the respective phase in each generator and cause the first generator and the second generator to be in-phase. The second generator is then mechanically coupled to the engine.

Abstract: An aircraft engine that includes an engine core having a core compressor and a core turbine for receiving a core flow, a bypass conduit for receiving a bypass flow, a heat exchanger having at least one first passage and at least one second passage in heat exchange relationship with one another, and a turbocharger having a turbocharger compressor and a turbocharger turbine in driving engagement with each other. An inlet of the turbocharger compressor is in fluid communication with an environment of the aircraft engine. An outlet of the turbocharger compressor is fluidly connected to the bypass conduit through the at least one first passage of the heat exchanger. The core compressor is fluidly connected to an inlet of the turbocharger turbine through the at least one second passage of the heat exchanger such that the turbocharger turbine is located downstream of the heat exchanger relative to a flow circulating in the at least one second passage.

Abstract: A cooling system for a gas turbine engine comprising a closed circuit containing a change-phase fluid, the closed circuit having at least one cooling exchanger configured to be exposed to a flow of cooling air for the change-phase fluid to release heat to the cooling air. A plurality of heat exchangers in are heat exchange relation with the change-phase fluid in the closed circuit, the plurality including at least a first heat exchanger configured to receive a first coolant from a first engine system for the change-phase fluid to absorb heat from the first coolant, and a second heat exchanger configured to receive a second coolant from a second engine system for the change-phase fluid to absorb heat from the second coolant. The system is configured so that the fluid at least partially vaporizes when absorbing heat from at least one of the first coolant and the second coolant and at least partially condenses when releasing heat to the cooling air.

Abstract: A cooling system for a gas turbine engine comprises a closed circuit containing a change-phase fluid, at least one heat exchanger configured to receive a first coolant from a first engine system for the change-phase fluid in the closed circuit to absorb heat from the first coolant, whereby the cooling system is configured so that the change-phase fluid at least partially vaporizes when absorbing heat from the at least one heat exchanger. The closed circuit has a cooling exchanger adjacent to an annular wall of a bypass duct, the cooling exchanger configured to be exposed to a flow of cooling air in the bypass duct for the change-phase fluid to release heat to the cooling air and condense at least partially, the cooling exchanger having conduits configured to feed the vaporized change-phase fluid from a heat exchange with the at least one heat exchanger to the cooling exchanger, and to direct condensed change-phase fluid by gravity from the cooling exchanger to the at least one heat exchanger.

Abstract: A turbine case cooling system and a method for supplying a cooling gas flow are provided. The cooling system has a turbine case and a turbine case cooling manifold. The cooling system also has a fluid or cooling conduit. The cooling conduit has an inlet in fluid communication with the bypass duct, and an outlet in fluid communication with the cooling manifold. The cooling conduit also has an ejector section which in use supplies a motive air flow radially into the cooling conduit to draw a bypass air flow from the bypass duct. The motive air flow mixes with the bypass air flow to form the cooling gas flow. The cooling conduit also has a diffuser section which in use conveys the cooling gas flow toward the outlet in a direction substantially perpendicular to the center axis of the gas turbine engine.

Abstract: A fan nose cone is disclosed for impeding icing and recovering momentum in a gas turbine engine. The fan nose cone comprises: an axially symmetric shell having a convex external surface and an internal surface, the shell having an opening in a forward end of the shell for communication with a source of heated pressurized air; and an axially symmetric deflector disposed forward of the opening, the deflector being configured to direct heated pressurized air exiting from the opening radially outwardly to flow in a downstream direction over the convex external surface of the shell during operation. The shell of the fan nose cone may have a rearward circumferential vent in communication with the source of heated pressurized air for directing heated pressurized from the vent in a radially outward and downstream direction toward the fan blade platforms.

Abstract: Multi-engine aircraft power plants and associated operating methods are disclosed. An exemplary multi-engine power plant comprises a first turboshaft engine and a second turboshaft engine configured to drive a common load such as a rotary wing of an aircraft; and a heat exchanger in thermal communication with an exhaust gas of the first turboshaft engine and in thermal communication with pre-combustion air of the second turboshaft engine. The heat exchanger is configured to permit heat transfer from the exhaust gas of the first turboshaft engine to the pre-combustion air of the second turboshaft engine.

Abstract: A gas turbine engine recuperator recuperator including exhaust passages providing fluid flow communication between an exhaust inlet and an exhaust outlet, the exhaust inlet being oriented to receive exhaust flow from a turbine of the engine and the exhaust outlet being oriented to deliver the exhaust flow to atmosphere, the exhaust passages having an arcuate profile in a plane perpendicular to a central axis of the recuperator to reduce a swirl of the exhaust flow. Air passages are in heat exchange relationship with the exhaust passages and providing fluid flow communication between an air inlet and an air outlet, design to sealingly respective plenum of the gas turbine engine.

Abstract: A method of manufacturing a recuperator segment uses metal tubes deformed into air cells in a waved configuration. The air cells are stacked one to another to form a double skinned recuperator segment providing cold air passages through the respective air cells and hot gas passages through spaces between adjacent air cells.

Abstract: A method for providing an anti-icing airflow, including extracting a compressed airflow from a core flow path of an engine, heating the compressed airflow, mixing the heated compressed airflow with air extracted from a bypass flow path to create the anti-icing airflow having a higher temperature and pressure than that of the air extracted from the bypass flow path, and circulating the anti-icing airflow away from the bypass flow path. Also, an assembly located at least in part inside a turbofan engine and including a heat exchanger, a flow mixing device having a first inlet in the bypass flow path, a second inlet and an outlet, a first conduit providing fluid communication between the heat exchanger and a compressed air portion of the core flow path, a second conduit providing fluid communication between the heat exchanger and the second inlet, and a third conduit in fluid communication with the outlet.

Abstract: A method of manufacturing a recuperator disposed in the exhaust duct of a gas turbine engine includes forming a first leading recess adjacent a leading edge of a first thermally conductive sheet and forming a second leading recess adjacent a leading edge of a second thermally conductive sheet, the first and second thermally conductive sheets forming components of a recuperator plate. The first leading recess of the first thermally conductive sheet is mated with the second leading recess of the second thermally conductive sheet, and then the first and second leading edges are joined thereby forming a recuperator plate. The first and second leading recesses form a trough extending along a leading edge of the recuperator plate in a direction substantially parallel to a longitudinal axis of the recuperator plate.

Abstract: A gas turbine engine recuperator recuperator including exhaust passages providing fluid flow communication between an exhaust inlet and an exhaust outlet, the exhaust inlet being oriented to receive exhaust flow from a turbine of the engine and the exhaust outlet being oriented to deliver the exhaust flow to atmosphere, the exhaust passages having an arcuate profile in a plane perpendicular to a central axis of the recuperator to reduce a swirl of the exhaust flow. Air passages are in heat exchange relationship with the exhaust passages and providing fluid flow communication between an air inlet and an air outlet, design to sealingly respective plenum of the gas turbine engine.

Abstract: A recuperator disposed in the exhaust duct of a gas turbine engine includes a plurality of recuperator plates arranged in a spaced-apart relationship to define therebetween a plurality of interstices and fluid channels, the plurality of interstices adapted to direct therethrough at least one first stream received at a leading plate edge of the recuperator plates and the plurality of fluid channels adapted to direct therethrough at least one second stream to effect heat exchange between the at least one first stream and the at least one second stream. Each recuperator plate includes, formed at the leading plate edge thereof, a first concavity extending along the leading edge in a direction substantially parallel to a longitudinal axis of the plate. The first concavity extends transversely to a direction of the at least one first stream flowing over each recuperator plate.

Abstract: An oil tank and scavenge pipe assembly of a gas turbine engine comprises a tank, and a scavenge pipe having a discharge portion disposed inside the tank. The discharge portion comprises a first portion having first and second ends. The first end is adapted to connect to an oil return line for receiving a mixture of oil and air. A bend extends from the second end downstream thereof relative to a flow of the mixture of oil and air through the scavenge pipe. The bend is configured to cause stratification of the mixture of oil and air as the mixture of oil and air flows through it. An outlet downstream of the bend delivers the mixture of oil and air to the tank. A method of delivering an oil and air mixture to a rotating oil volume of a tank of a gas turbine engine is also presented.

Abstract: An air-to-air cooler has a heat exchanger integrated to a housing. A first passage extends through the housing for directing a flow of cooling air through the heat exchanger. A second passage extends through the housing for directing a flow of hot air to be cooled through the heat exchanger. The first passage has a cooling air outlet tube disposed downstream of the heat exchanger. The cooling air outlet tube extends across the second passage between the heat exchanger and a hot air inlet of the second passage. The hot air inlet is disposed to cause incoming hot air to flow over the cooling air outlet tube upstream of the heat exchanger. An ejector drives the flow of cooling air through the first passage of the air-to-air cooler. A portion of the hot air flow may be used to drive the ejector.

Abstract: The liquid cooling system has a heat exchanger having a fluid inlet and an outlet; a fluid supply conduit leading to the inlet of the heat exchanger; a fluid return conduit extending from the outlet of the heat exchanger; a bypass conduit extending between the fluid supply conduit and the fluid return conduit; a thermal valve configured for selectively closing the bypass conduit, the valve having a temperature sensing element positioned downstream of both the heat exchanger and the bypass conduit, the temperature sensing element configured to selectively move the thermal valve in response to a temperature change of the liquid which the temperature sensing element is exposed to relative to a temperature threshold of the valve; and a deflector positioned between the temperature sensing element and at least one of the bypass conduit and the heat exchanger outlet.

Abstract: An oil tank and scavenge pipe assembly of a gas turbine engine comprises a tank, and a scavenge pipe having a discharge portion disposed inside the tank. The discharge portion comprises a first portion having first and second ends. The first end is adapted to connect to an oil return line for receiving a mixture of oil and air. A bend extends from the second end downstream thereof relative to a flow of the mixture of oil and air through the scavenge pipe. The bend is configured to cause stratification of the mixture of oil and air as the mixture of oil and air flows through it. An outlet downstream of the bend delivers the mixture of oil and air to the tank. A method of delivering an oil and air mixture to a rotating oil volume of a tank of a gas turbine engine is also presented.