A combustion section defines an axial direction, a radial direction, and a circumferential direction. The combustion section includes a casing that defines a diffusion chamber. A combustion liner is disposed within the diffusion chamber and defines a combustion chamber the combustion liner is spaced apart from the casing such that a passageway is defined between the combustion liner and the casing. A fuel cell assembly is disposed in the passageway. The fuel cell assembly includes a fuel cell stack that has a plurality of fuel cells each extending between an inlet end and an outlet end. The inlet end receives a flow of air and fuel and the outlet end provides output products to the combustion chamber. The fuel cell assembly further includes an electrical circuit that is electrically coupled to the plurality of fuel cells and that extends through the casing.

An integrated hydrogen-electric engine includes a hydrogen fuel-cell; a hydrogen fuel source; an electric motor assembly disposed in electrical communication with the fuel-cell; an air compressor system configured to be driven by the motor assembly, and a cooling system having a heat exchanger radiator in a duct of the cooling system, and configured to direct an air stream including an air stream from the air compressor through the radiator, wherein an exhaust stream from a cathode side of the fuel-cell is fed via a flow control nozzle into the air stream in the cooling duct downstream of the radiator.

An engine system for an aircraft includes a gas turbine engine and a control system. The control system is configured to motor the gas turbine engine, absent fuel burn, during a taxi mode of the aircraft. The control system is further configured to accelerate a motoring speed of the gas turbine engine, absent fuel burn, above an idle speed of the gas turbine engine to provide propulsion during the taxi mode. The control system is configured to decrease the motoring speed of the gas turbine engine, absent fuel burn, based on a change in a starting mode of the gas turbine engine or the aircraft reaching a targeted new position.

A flying vehicle propulsion system including a propulsor, a drive system and a heat exchanger. The drive system is arranged to drive the propulsor and the heat exchanger is arranged to thermally regulate at least part of the drive system. The propulsor is arranged to move fluid, thereby producing a propulsor fluid flow having a main direction. The system is arranged such that in a first operation configuration, at least part of the propulsor fluid flow is incident on the heat exchanger, thereby thermally regulating the at least part of the drive system.

A flying vehicle propulsion system including a propulsor, a drive system and a heat exchanger. The drive system is arranged to drive the propulsor and the heat exchanger is arranged to thermally regulate at least part of the drive system. The propulsor is arranged to move fluid, thereby producing a propulsor fluid flow having a main direction. The system is arranged such that in a first operation configuration, at least part of the propulsor fluid flow is incident on the heat exchanger, thereby thermally regulating the at least part of the drive system.

A carrier structure for electrodes of a fuel cell. The structure has a duct wall and a tubular ducting volume. The duct wall forms the tubular ducting volume and includes an outer surface facing a surrounding and an inner surface facing the tubular ducting volume. The tubular ducting volume conducts a first supply flow comprising an oxidant. The duct wall provides a second supply flow within the duct wall, the second supply flow being a reductant. The duct wall separates the first supply flow in the tubular ducting volume from the second supply flow within the duct wall and the surrounding of the carrier structure. A primary power coating layer is applied on the inner surface of the duct wall, arranged between the first supply flow and the second supply flow. The coating layer generates electrical energy from the first supply flow and the second supply flow.

A carrier structure for electrodes of a fuel cell. The structure has a duct wall and a tubular ducting volume. The duct wall forms the tubular ducting volume and includes an outer surface facing a surrounding and an inner surface facing the tubular ducting volume. The tubular ducting volume conducts a first supply flow comprising an oxidant. The duct wall provides a second supply flow within the duct wall, the second supply flow being a reductant. The duct wall separates the first supply flow in the tubular ducting volume from the second supply flow within the duct wall and the surrounding of the carrier structure. A primary power coating layer is applied on the inner surface of the duct wall, arranged between the first supply flow and the second supply flow. The coating layer generates electrical energy from the first supply flow and the second supply flow.

A power source assembly is provided having a fuel cell module configured to provide a first direct current power output; a battery module configured to provide a second direct current power output; a direct current electric bus configured to provide a net direct current power output to a load; a DC/DC converter in electrical connection with the direct current electric bus, the DC/DC converter configured to receive the first direct current power output from the fuel cell module or the second direct current power output from the battery module; and a controller operably coupled to the DC/DC converter and configured to receive data indicative of the first direct current power output, the controller configured to control the DC/DC converter based on the data indicative of the first direct current power output to maintain a slew rate from the fuel cell module within a slew rate range.

A method and a system for starting a fuel cell at temperatures below 0 Celsius with a two-phase cooling system are indicated, whereby the two-phase cooling system has a pump to convey a coolant present in the two-phase cooling system, whereby the coolant is present at least partially in a gas phase in the two-phase cooling system, including steps of starting the fuel cell, and activating the pump after a defined period of time, whereby the coolant is present substantially in the gas phase within the fuel cell during the defined period of time.

A method and a system for starting a fuel cell at temperatures below 0 Celsius with a two-phase cooling system are indicated, whereby the two-phase cooling system has a pump to convey a coolant present in the two-phase cooling system, whereby the coolant is present at least partially in a gas phase in the two-phase cooling system, including steps of starting the fuel cell, and activating the pump after a defined period of time, whereby the coolant is present substantially in the gas phase within the fuel cell during the defined period of time.