Abstract: A heat exchange system for an aircraft engine, has: a fuel conduit; an oil conduit; a first heat exchanger having a fuel passage and an oil passage, the fuel passage in heat exchange relationship with the oil passage; and a second heat exchanger having a fluid passage and an air passage fluidly in heat exchange relationship with the fluid passage, the air passage in fluid communication with a compressor, the fluid passage in fluid communication with one of: the oil conduit, the fluid passage flowing at least part of the oil flow through the fluid passage, the fluid passage of the second heat exchanger located upstream of the oil passage of the first heat exchanger relative to the oil flow, and the fuel conduit, the fluid passage flowing at least part of the fuel flow through the fluid passage.

Abstract: An oil cooling system for an aircraft engine, a bypass valve and an associate method of cooling aircraft engine oil are provided. The oil cooling system includes a heat exchanger having an inlet and an outlet. The inlet is in fluid communication with a first oil conduit to receive a first oil flow from the first oil conduit. The heat exchanger facilitates heat transfer from the first oil flow to another fluid. A flow restrictor defining a constriction is operatively disposed to restrict the first oil flow through the heat exchanger. A second oil conduit receives the first oil flow from the heat exchanger. A bypass oil passage provides fluid communication between the first oil conduit and the second oil conduit to allow a second oil flow received from the first oil conduit to flow to the second oil conduit and bypass the heat exchanger.

Abstract: An oil cooling system for an aircraft engine, a bypass valve and an associate method of cooling aircraft engine oil are provided. The oil cooling system includes a heat exchanger having an inlet and an outlet. The inlet is in fluid communication with a first oil conduit to receive a first oil flow from the first oil conduit. The heat exchanger facilitates heat transfer from the first oil flow to another fluid. A flow restrictor defining a constriction is operatively disposed to restrict the first oil flow through the heat exchanger. A second oil conduit receives the first oil flow from the heat exchanger. A bypass oil passage provides fluid communication between the first oil conduit and the second oil conduit to allow a second oil flow received from the first oil conduit to flow to the second oil conduit and bypass the heat exchanger.

Abstract: A heat exchange system for an aircraft engine includes a heat exchanger, a main conduit directing fuel to a combustion chamber of the aircraft engine, and a pump connected to the main conduit. A return conduit receives excess fuel outputted by the pump and exceeding a fuel requirement of the combustion chamber. The return conduit, which is connected to a fuel conduit of the heat exchanger, has an inlet connected to the main conduit downstream of the pump and an outlet connected to the main conduit upstream of the pump. An actuator has an inlet connected to the main conduit downstream of the pump and an outlet connected to the main conduit upstream of the pump while bypassing the heat exchanger, wherein a pressure differential between the actuator inlet and the actuator outlet remains substantially unchanged with variations of a fuel flow through the heat exchanger.

Abstract: Apparatus and methods for controlling a pressure differential across one or more seals of a bearing chamber in a gas turbine engine are disclosed. In some embodiments, the apparatus comprises a scavenge pump in fluid communication with an interior of the bearing chamber for driving oil from the bearing chamber; and a venting valve. The venting valve is configured to cause venting of the interior of the bearing chamber in parallel to the scavenge pump based on the pressure differential across the one or more seals.

Abstract: Apparatus and methods for controlling a pressure differential across one or more seals of a bearing chamber in a gas turbine engine are disclosed. In some embodiments, the apparatus comprises a scavenge pump in fluid communication with an interior of the bearing chamber for driving oil from the bearing chamber; and a venting valve. The venting valve is configured to cause venting of the interior of the bearing chamber in parallel to the scavenge pump based on the pressure differential across the one or more seals.

Abstract: A scavenge gear pump and its method of operation is described. The scavenge gear pump includes a pump housing defining a pump chamber, an inlet passage, an outlet passage, and a fluid injection passage in fluid communication with the pump chamber. The inlet passage receives an admixed fluid at low pressure and the outlet passage the admixed fluid at high pressure from a downstream region of said pump chamber. The fluid injection passage receives a third fluid at an injection pressure for input into the pump chamber. A pair of driveable gears is disposed in the pump chamber. The third fluid is injected directly into the gear meshing area of the pump chamber through the fluid injection passage so that the third fluid fills voids at least between said intermeshing teeth of the driveable gears and so that the second fluid does not occupy the gear meshing area.

Abstract: A lubrication system for a gas turbine engine including at least one porous element located in a cavity containing at least one rotating component receiving a flow of the lubricant, the porous element being located across a path taken by a portion of the lubricant expelled from the at least one respective rotating component such that the portion of the lubricant circulates therethrough, the at least one porous element being made of a material resistant to a temperature of the lubricant, the at least one porous element reducing a velocity of the portion of the lubricant circulating therethrough.

Abstract: A scavenge gear pump and its method of operation is described. The scavenge gear pump defines a pump chamber in which a pair of toothed gears are rotatably driven to pump an oil-air mixture from an inlet passage where the oil mixture is at low pressure, to an outlet passage where the air and oil has separated and is at high pressure. The gears are intermeshed in a meshing area between the inlet and the outlet passages and an oil nozzle is provided in a downstream region disposed in relation to the gear meshing area to inject oil under pressure in that area to occupy the volumes between the intermeshed gear teeth whereby to prevent air bubbles from being carried back to an upstream region adjacent the inlet passage. Accordingly, the volumetric efficiency of the pump is improved and it is more tolerant to back pressure.

Abstract: A lubrication system for a gas turbine engine including at least one porous element located in a cavity containing at least one rotating component receiving a flow of the lubricant, the porous element being located across a path taken by a portion of the lubricant expelled from the at least one respective rotating component such that the portion of the lubricant circulates therethrough, the at least one porous element being made of a material resistant to a temperature of the lubricant, the at least one porous element reducing a velocity of the portion of the lubricant circulating therethrough.