Abstract: Turbomachinery comprising first and second sets of rotors configured to operate on a working fluid. The machinery further comprises first and second sets of electric machines coupled to the respective first and second rotors, and a coupling arrangement arranged to couple adjacent rotors of the first and second rotor sets to provide for fixed ratio, contra-rotation of the first and second rotor sets.

Abstract: A superconducting electrical power distribution system has a superconducting bus bar and one or more bus bar thermal conductor lines extending in thermal proximity along the bus bar to receive heat from the bus bar over the length of the bus bar. The system further has superconducting cables electrically connected to the bus bar at respective electrical joints distributed along the bus bar. The system further has a cryogenic cooling sub-system. The system further has a network comprising first and second thermal conductor lines, each line comprising a cold end which is cooled by the cryogenic cooling sub-system, and an opposite hot end, whereby heat received by each line is normally conducted along the line in a direction from its hot end to its cold end.

Abstract: A superconducting electrical power distribution network has a superconducting bus bar and superconducting cables electrically connected to the bus bar at respective joints distributed along the bus bar. The network further has a first coolant system for providing first cryogenic fluid and first circuits for circulating the first cryogenic fluid provided by the first coolant system. The first circuits comprise: a bus bar flow path which extends along and thereby cools the bus bar, cable flow paths which respectively extend along and thereby cool the cables, cooling junctions where the bus bar and cable flow paths meet at the electrical connection joints, inflow lines which send the first cryogenic fluid from the first coolant system to the flow paths, and outflow lines which remove the first cryogenic fluid from the flow paths.

Abstract: A method of controlling a reciprocating internal combustion engine comprising: a cylinder defining a cavity having a first end and a second end; and a piston moveable within the cavity of the cylinder between the first end and the second end, the method comprising: controlling injection of a quantity of liquid air, without fuel, into the first end of the cavity at a first time when the piston is closer to the first end than the second end to cause the piston to perform a first power stroke; and controlling injection of fuel into the first end of the cavity at a second time when the piston is closer to the first end than the second end to cause the piston to perform a second power stroke.

Abstract: The present disclosure concerns a heat exchanger, which may for example be utilised in a gas turbine engine or in other applications. Example embodiments include a heat exchanger comprising: an external surface for exchanging heat with an external fluid flow passing over the external surface; a first fluid passage extending through the heat exchanger from a first fluid inlet to a first fluid outlet, a first portion of the first fluid passage extending along the heat exchanger adjacent to the external surface for a first cooling fluid passing through the first fluid passage to exchange heat with the external fluid flow; and a second fluid passage extending through the heat exchanger from a second fluid inlet to a second fluid outlet located at the external surface for a second cooling fluid to pass from the second fluid inlet into the external fluid flow.

Abstract: An epicyclic geartrain includes a debris collection arrangement. The epicyclic geartrain comprises a sun gear, a plurality of planet gears, with the plurality of planet gears being supported by a planet torque ring, and a ring gear. The planet gears meshingly surround the sun gear, and the ring gear meshingly surrounds the planet gears. At least one of the sun gear, the plurality of planet gears, and the ring gear, is provided with a plurality of permanent magnet portions, and a debris collection element. The plurality of magnet portions is arranged as a circumferential array across a side of the corresponding gear. The debris collection element extends along the side face of the gear. The debris collection element is slidably positioned against the side face, such that rotation of the gear causes the debris collection element to remove any ferromagnetic debris particles that are magnetically attached to the side face.

Abstract: A method of controlling a reciprocating internal combustion engine comprising: a cylinder defining a cavity having a first end and a second end; and a piston moveable within the cavity of the cylinder between the first end and the second end, the method comprising: receiving at least a first signal; determining a quantity of liquid air to be injected using at least the received first signal; controlling injection of the determined quantity of liquid air into the first end of the cavity at a first time when the piston is closer to the first end than the second end.

Abstract: An epicyclic geartrain comprises a sun gear, a plurality of planet gears, and a ring gear. The plurality of planet gears is supported by a planet torque ring. The planet gears meshingly surround the sun gear, and the ring gear meshingly surrounds the planet gears. At least one of the sun gear, the plurality of planet gears, and the ring gear, is provided with a plurality of permanent magnet portions. Each of the plurality of magnet portions is arranged as a circumferential array. The planet torque ring is provided with at least one stator coil array, with the or each stator coil array being positioned in axial alignment with the or each corresponding plurality of permanent magnet portions as an axial flux electric motor generator element.

Abstract: A combined refrigeration and power plant. The power plant comprises an internal combustion engine an air cycle machine refrigerator driven by the internal combustion engine and configured to refrigerate atmospheric air to provide working fluid to combined refrigeration and power generation cycle, a refrigerated air storage unit configured to store working fluid produced by the air cycle machine refrigerator; and first and second heat exchangers. The first heat exchanger arrangement is configured to exchange heat between a device to be cooled and the working fluid, and the second heat exchanger arrangement is configured to exchange heat between the working fluid downstream of the first heat exchanger in the combined refrigeration and power generation cycle and waste heat from the internal combustion engine; and a generator turbine configured to receive heated working fluid from the second heat exchanger arrangement, and configured to power an electrical generator.

Abstract: A superconducting fault current limiter (10) is shown. It comprises a cryostatic cooling system (20) for containing a cooling medium (26), a superconducting wire (30) immersed in the cooling medium (26) and configured to carry a current, the superconducting wire (30) becoming non-superconducting above a critical current density, and a plurality of heat dissipation elements spaced along and projecting from the superconducting wire (30), wherein the heat dissipation elements have an electrically insulating coating, and whereby the heat dissipation elements transfer heat from the superconducting wire (30) into the cooling medium (26).

Abstract: An epicyclic geartrain includes a debris collection arrangement. The epicyclic geartrain comprises a sun gear, a plurality of planet gears, with the plurality of planet gears being supported by a planet torque ring, and a ring gear. The planet gears meshingly surround the sun gear, and the ring gear meshingly surrounds the planet gears. At least one of the sun gear, the plurality of planet gears, and the ring gear, is provided with a plurality of permanent magnet portions, and a debris collection element. The plurality of magnet portions is arranged as a circumferential array across a side of the corresponding gear. The debris collection element extends along the side face of the gear. The debris collection element is slidably positioned against the side face, such that rotation of the gear causes the debris collection element to remove any ferromagnetic debris particles that are magnetically attached to the side face.

Abstract: An epicyclic geartrain comprises a sun gear, a plurality of planet gears, and a ring gear. The plurality of planet gears is supported by a planet torque ring. The planet gears meshingly surround the sun gear, and the ring gear meshingly surrounds the planet gears. At least one of the sun gear, the plurality of planet gears, and the ring gear, is provided with a plurality of permanent magnet portions. Each of the plurality of magnet portions is arranged as a circumferential array. The planet torque ring is provided with at least one stator coil array, with the or each stator coil array being positioned in axial alignment with the or each corresponding plurality of permanent magnet portions as an axial flux electric motor generator element.

Abstract: A method of controlling a reciprocating internal combustion engine comprising: a cylinder defining a cavity having a first end and a second end; and a piston moveable within the cavity of the cylinder between the first end and the second end, the method comprising: receiving at least a first signal; determining a quantity of liquid air to be injected using at least the received first signal; controlling injection of the determined quantity of liquid air into the first end of the cavity at a first time when the piston is closer to the first end than the second end.

Abstract: A method of controlling a reciprocating internal combustion engine comprising: a cylinder defining a cavity having a first end and a second end; and a piston moveable within the cavity of the cylinder between the first end and the second end, the method comprising: controlling injection of a quantity of liquid air, without fuel, into the first end of the cavity at a first time when the piston is closer to the first end than the second end to cause the piston to perform a first power stroke; and controlling injection of fuel into the first end of the cavity at a second time when the piston is closer to the first end than the second end to cause the piston to perform a second power stroke.