A gas turbine engine comprises a bypass duct and a heat exchanger assembly, the heat exchanger assembly comprising a heat exchanger and a heat exchanger duct having an inlet region, an inflection region and an outlet region. A direction of a centreline of the heat exchanger duct has a tangential component with respect to a principal rotational axis of the gas turbine engine at one or more of the inlet region, the inflection region and the outlet region. The heat exchanger is disposed within the inflection region and configured to transfer heat generated by the gas turbine engine into the flow of air as it passes through the inflection region.

A gas turbine engine assembly includes a core engine that includes a core flow path where a core airflow is compressed in a compressor section, communicated to a combustor section, mixed with fuel and ignited to generate a high energy combusted gas flow that is expanded through a turbine section, a first tap at a location up stream of the combustor section for communicating a portion of the core airflow as a bleed airflow downstream of the combustor section, a heat exchanger that places the bleed airflow that is communicated from the first tap in thermal communication with the high energy combusted gas flow downstream of the combustor section, and a power turbine that is configured to generate shaft power from expansion of the heated bleed airflow, the power turbine includes an inlet that is configured to receive the heated bleed airflow from the heat exchanger.

A gas turbine engine assembly includes a core engine that includes a core flow path where a core airflow is compressed in a compressor section, communicated to a combustor section, mixed with fuel and ignited to generate a high energy combusted gas flow that is expanded through a turbine section, a first tap at a location up stream of the combustor section for communicating a portion of the core airflow as a bleed airflow downstream of the combustor section, a heat exchanger that places the bleed airflow that is communicated from the first tap in thermal communication with the high energy combusted gas flow downstream of the combustor section, and a power turbine that is configured to generate shaft power from expansion of the heated bleed airflow, the power turbine includes an inlet that is configured to receive the heated bleed airflow from the heat exchanger.

An aircraft propulsion assembly includes a turbine engine surrounded by a nacelle with an annular air-intake lip extending around the turbine engine by two annular walls, inner and outer, respectively, intended for being swept across by air flows at least when the aircraft is in flight. The inner and outer walls each includes or supports at least one network of pipes forming heat exchangers. The inner wall pipe network having liquid outlet connected with a liquid intake of the outer wall pipe network. The propulsion assembly further includes means for circulating the liquid, connected to at least one liquid intake of the network of pipes of the inner wall.

An aircraft propulsion assembly includes a turbine engine surrounded by a nacelle with an annular air-intake lip extending around the turbine engine by two annular walls, inner and outer, respectively, intended for being swept across by air flows at least when the aircraft is in flight. The inner and outer walls each includes or supports at least one network of pipes forming heat exchangers. The inner wall pipe network having liquid outlet connected with a liquid intake of the outer wall pipe network. The propulsion assembly further includes means for circulating the liquid, connected to at least one liquid intake of the network of pipes of the inner wall.

A system and method for adaptively controlling a cooldown cycle of an auxiliary power unit (APU) that is operating and rotating at a rotational speed includes reducing the rotational speed of the APU to a predetermined cooldown speed magnitude that ensures combustor inlet temperature has reached a predetermined temperature value, determining, based on one or more of operational parameters of the APU, when a lean blowout of the APU is either imminent or has occurred, and when a lean blowout is imminent or has occurred, varying one or more parameters associated with the shutdown/cooldown cycle.

A system and method for adaptively controlling a cooldown cycle of an auxiliary power unit (APU) that is operating and rotating at a rotational speed includes reducing the rotational speed of the APU to a predetermined cooldown speed magnitude that ensures combustor inlet temperature has reached a predetermined temperature value, determining, based on one or more of operational parameters of the APU, when a lean blowout of the APU is either imminent or has occurred, and when a lean blowout is imminent or has occurred, varying one or more parameters associated with the shutdown/cooldown cycle.

A heat exchanger includes a plurality of fins arranged as a network and delimiting corridors, and an envelope having an internal wall and an external wall, the internal and external walls delimiting between them a channel for a flow of a first fluid in a main direction, the network of fins being arranged in the channel and connected to the internal and external walls, at least one passage for a flow of a second fluid being embedded in at least one of the internal and external walls, the channel being, in the main direction, divergent and then convergent.

A system and method of increasing the temperature of oil that is used to anti-ice a gas turbine propulsion engine includes supplying oil from an oil supply system to an anti-ice oil circulation system that is disposed within the front frame of the gas turbine propulsion engine, and selectively injecting compressed air from the gas turbine propulsion engine into the oil supply system.

A system and method of increasing the temperature of oil that is used to anti-ice a gas turbine propulsion engine includes supplying oil from an oil supply system to an anti-ice oil circulation system that is disposed within the front frame of the gas turbine propulsion engine, and selectively injecting compressed air from the gas turbine propulsion engine into the oil supply system.