Combustor systems are provided that include rotating detonation combustors (RDCs) arranged in series. In some embodiments, a combustor system includes a volume that receives a core oxidizer-fuel mixture. The combustor system includes a first RDC having a first detonation chamber. The first detonation chamber receives a first pilot oxidizer-fuel mixture and is bounded by a first channel formed in a peripheral wall. The combustor system further includes at least one additional RDC having a second detonation chamber. The second detonation chamber receives a second pilot oxidizer-fuel mixture and is bounded by a second channel formed in the peripheral wall. The first pilot oxidizer-fuel mixture reacts in the first detonation chamber and the second pilot oxidizer-fuel mixture reacts in the second detonation chamber to generate rotating detonation combustion waves that are guided by the first channel and the second channel to support a reaction that consumes the core oxidizer-fuel mixture.

A turboprop engine assembly for an aircraft, including an internal combustion engine having a liquid coolant system, an air duct in fluid communication with an environment of the aircraft, a heat exchanger received within the air duct having coolant passages in fluid communication with the liquid coolant system and air passages air passages in fluid communication with the air duct, and an exhaust duct in fluid communication with an exhaust of the internal combustion engine. The exhaust duct has an outlet positioned within the air duct downstream of the heat exchanger and upstream of an outlet of the air duct, the outlet of the exhaust duct spaced inwardly from a peripheral wall of the air duct. In use, a flow of cooling air surrounds a flow of exhaust gases. A method of discharging air and exhaust gases in an turboprop engine assembly having an internal combustion engine is also discussed.

An auxiliary power unit for an aircraft, including an internal combustion engine having a liquid coolant system, a generator drivingly engaged to the internal combustion engine and having a liquid coolant system distinct from the liquid coolant system of the internal combustion engine, a first heat exchanger in fluid communication with the liquid coolant system of the internal combustion engine, a second heat exchanger in fluid communication with the liquid coolant system of the generator, an exhaust duct in fluid communication with air passages of the heat exchangers, and a fan received in the exhaust duct and rotatable by the internal combustion engine for driving a cooling air flow through the air passages. The liquid coolant system of the engine may be distinct from fuel and lubricating systems of the auxiliary power unit. A method of cooling a generator and an internal combustion engine is also discussed.

A combustor for a rotating detonation engine includes a radially outer wall extending along an axis (A); a radially inner wall extending along the axis (A), wherein the radially inner wall is positioned within the radially outer wall to define an annular detonation chamber having an inlet for fuel and oxidant and an outlet; a first passage for feeding at least one of the fuel and the oxidant along a first passage axis (a.sub.1) to the inlet; a second passage for feeding at least one of the fuel and the oxidant along a second passage axis (a.sub.2) to the inlet, wherein the second passage axis is arranged at an angle () relative to the first passage axis whereby mixing of flow from the first passage and the second passage is induced.

A combustor for a rotating detonation engine includes a radially outer wall extending along an axis (A); a radially inner wall extending along the axis (A), wherein the radially inner wall is positioned within the radially outer wall to define an annular detonation chamber having an inlet for fuel and oxidant and an outlet; a first passage for feeding at least one of the fuel and the oxidant along a first passage axis (a.sub.1) to the inlet; a second passage for feeding at least one of the fuel and the oxidant along a second passage axis (a.sub.2) to the inlet, wherein the second passage axis is arranged at an angle () relative to the first passage axis whereby mixing of flow from the first passage and the second passage is induced.

A rotating detonation engine comprising: an outer cylinder that extends in an axial direction; a base that is connected to the outer cylinder, and comprises a plurality of fuel injection ports positioned in a circular ring shape and injecting a fuel, and a plurality of oxidizing agent injection ports positioned in a circular ring shape and injecting an oxidizing agent; an inner cylinder that is positioned in the outer cylinder, and is positioned in the axial direction relative to the base; and a mechanism that switches a combustion space, wherein the combustion space is switched in accordance with a combustion mode.

Combustor systems are provided that include rotating detonation combustors (RDCs) arranged in series. In some embodiments, a combustor system includes a volume that receives a core oxidizer-fuel mixture. The combustor system includes a first RDC having a first detonation chamber. The first detonation chamber receives a first pilot oxidizer-fuel mixture and is bounded by a first channel formed in a peripheral wall. The combustor system further includes at least one additional RDC having a second detonation chamber. The second detonation chamber receives a second pilot oxidizer-fuel mixture and is bounded by a second channel formed in the peripheral wall. The first pilot oxidizer-fuel mixture reacts in the first detonation chamber and the second pilot oxidizer-fuel mixture reacts in the second detonation chamber to generate rotating detonation combustion waves that are guided by the first channel and the second channel to support a reaction that consumes the core oxidizer-fuel mixture.

Combustor systems are provided that include rotating detonation combustors (RDCs) arranged in series. In some embodiments, a combustor system includes a volume that receives a core oxidizer-fuel mixture. The combustor system includes a first RDC having a first detonation chamber. The first detonation chamber receives a first pilot oxidizer-fuel mixture and is bounded by a first channel formed in a peripheral wall. The combustor system further includes at least one additional RDC having a second detonation chamber. The second detonation chamber receives a second pilot oxidizer-fuel mixture and is bounded by a second channel formed in the peripheral wall. The first pilot oxidizer-fuel mixture reacts in the first detonation chamber and the second pilot oxidizer-fuel mixture reacts in the second detonation chamber to generate rotating detonation combustion waves that are guided by the first channel and the second channel to support a reaction that consumes the core oxidizer-fuel mixture.

A propulsion system for an aircraft includes an engine assembly and a turbocompressor. The engine assembly includes an engine and an interburner. The engine includes an engine output shaft. The engine is configured to drive rotation of a propulsor with the engine output shaft. The interburner is configured to mix and burn an exhaust gas from the engine with fuel to form a combustion gas. The turbocompressor includes a turbine and a compressor. The turbine and the compressor form a rotational assembly. The rotational assembly includes a shaft, a bladed turbine rotor of the turbine, and a bladed compressor rotor of the compressor. The turbine is connected in fluid communication with the interburner to receive the combustion gas. The compressor is connected in fluid communication with the engine to direct a compressed air to the engine. The rotational assembly is mechanically independent of the engine output shaft.

A propulsion system for an aircraft includes an engine assembly and a turbocompressor. The engine assembly includes an engine and an interburner. The engine includes an engine output shaft. The engine is configured to drive rotation of a propulsor with the engine output shaft. The interburner is configured to mix and burn an exhaust gas from the engine with fuel to form a combustion gas. The turbocompressor includes a turbine and a compressor. The turbine and the compressor form a rotational assembly. The rotational assembly includes a shaft, a bladed turbine rotor of the turbine, and a bladed compressor rotor of the compressor. The turbine is connected in fluid communication with the interburner to receive the combustion gas. The compressor is connected in fluid communication with the engine to direct a compressed air to the engine. The rotational assembly is mechanically independent of the engine output shaft.