A method, system, and apparatus for managing variable, multi-phase on-site electric power and fluid conversion to output fuel and energy for providing customizable management for processing hydrogen-based fuels. In particular, the method, system and apparatus provide for automated feedback and control, directing inputs for conversion including electrolysis to create fuel products including gaseous hydrogen and liquid hydrogen to be used in clean-fuel vehicles onsite or transported to be used for vehicle delivery, according to settings or system parameters to meet demand quickly and efficiently for various products while making adjustments in real time.

A method, system, and apparatus for managing variable, multi-phase on-site electric power and fluid conversion to output fuel and energy for providing customizable management for processing hydrogen-based fuels. In particular, the method, system and apparatus provide for automated feedback and control, directing inputs for conversion including electrolysis to create fuel products including gaseous hydrogen and liquid hydrogen to be used in clean-fuel vehicles onsite or transported to be used for vehicle delivery, according to settings or system parameters to meet demand quickly and efficiently for various products while making adjustments in real time.

An assembly with an aircraft fuel tank is disclosed having a captive nut with an internal thread, a secondary structure, and a fastener which secures the secondary structure to the fuel tank. The fastener has a shaft which passes through the secondary structure and has an external thread coupled to the internal thread of the captive nut. The fuel tank has a fuel tank element with a hole, and the captive nut has a sleeve which is located in the hole with an interference fit between an outer surface of the sleeve and an inner surface of the wall of the hole.

An assembly with an aircraft fuel tank is disclosed having a captive nut with an internal thread, a secondary structure, and a fastener which secures the secondary structure to the fuel tank. The fastener has a shaft which passes through the secondary structure and has an external thread coupled to the internal thread of the captive nut. The fuel tank has a fuel tank element with a hole, and the captive nut has a sleeve which is located in the hole with an interference fit between an outer surface of the sleeve and an inner surface of the wall of the hole.

A system for power and data communications within a fuel tank and across a wall of the fuel tank includes an optical hybrid fuel height sensor and a sealed connector extending through a wall of the fuel tank. The system also includes an electric power connection between the optical hybrid fuel height sensor and the sealed connector. The electric power connection includes a resistive non-metallic wire. The system also includes a sealed optical connector extending through the wall of the fuel tank. The system further includes an internal data communications connection between the optical hybrid fuel height sensor and the sealed optical connector. The internal data communications connection includes an optical signal out connection.

A system for power and data communications within a fuel tank and across a wall of the fuel tank includes an optical hybrid fuel height sensor and a sealed connector extending through a wall of the fuel tank. The system also includes an electric power connection between the optical hybrid fuel height sensor and the sealed connector. The electric power connection includes a resistive non-metallic wire. The system also includes a sealed optical connector extending through the wall of the fuel tank. The system further includes an internal data communications connection between the optical hybrid fuel height sensor and the sealed optical connector. The internal data communications connection includes an optical signal out connection.

Methods and apparatus are disclosed for a hydrogen aircraft with cryo-compressed storage. An example fuel distribution system includes a vacuum vessel, a cryogenic vessel positioned within the vacuum vessel, the cryogenic vessel part of a cryo-compressed hydrogen delivery assembly, and at least one of a heater or a thermosiphoning loop to maintain a pressure of the cryogenic vessel.

Systems and methods are provided for storage in at least one on-board fuel tank of aircraft fuel under a predetermined pressure and at an internal ambient tank temperature. A passive heat exchanger having an exchanger inlet is fluid-connected to a propulsion engine of the aircraft to receive heated pressurized bleed air therefrom while an exchanger outlet is fluid connected to the fuel tank. The passive heat exchanger is configured to cool the heated pressurized bleed air from the engine by heat transfer to a surrounding environment by radiation and convection so as to supply pressurization air to the fuel tank at the predetermined internal tank pressure and the internal ambient tank temperature. A system controller is provided to provide the fuel tank with pressurized air at a predetermined temperature during various aircraft flight phases.

A propulsion system according to an exemplary embodiment of this disclosure, among other possible things includes a fuel storage tank that is configured to store a fuel in a compressed state, a power generation device that is configured to consume the fuel and generate an output, a fuel system that is configured to provide the fuel from the fuel storage tank to the power generation device, and an electrochemical compressor that is in communication with the fuel system. The electrochemical compressor is configured to gather residual fuel from the fuel system and communicate the gathered residual fuel to at least one of the power generation device and the fuel storage tank.

A system for managing thermal transfer in at least one of an aircraft or a gas turbine engine includes a first engine system utilizing an oil for heat transfer. The oil of the first system has a temperature limit of at least about 500° F. The system additionally includes a fuel system having a deoxygenation unit for deoxygenating fuel in the fuel system, as well as a fuel-oil heat exchanger located downstream of the deoxygenation unit. The fuel-oil heat exchanger is in thermal communication with the oil in the first engine system and the fuel in the fuel system for transferring heat from the oil in the first engine system to the fuel in the fuel system.