Abstract: A fuel delivery system (201) is shown for delivering the hydrogen fuel from a cryogenic storage system to a fuel injection system in a gas turbine engine. The fuel delivery system includes a pump (301), a metering device (302), and a fuel heating system (303,304) for heating the hydrogen fuel to an injection temperature for the fuel injection system.

Abstract: A combined gas turbine engine and hydrogen fuel cell system includes a hydrogen fuelled gas turbine engine, a cryogenic liquid hydrogen fuel tank, a first fuel offtake configured and arranged to divert a portion of hydrogen fuel from a main fuel conduit, a burner configured and arranged to burn the portion of hydrogen fuel diverted from the main fuel conduit, a heat exchanger configured and arranged to transfer heat from exhaust gasses produced by the burner to hydrogen fuel in the main fuel conduit, a second fuel offtake arranged to divert a portion of hydrogen fuel from the main fuel conduit downstream of the heat exchanger, and a hydrogen fuel cell configured and arranged to produce electric power using hydrogen fuel diverted from the second fuel offtake.

Abstract: A gas turbine engine fuel system includes a fuel offtake configured to divert a portion of hydrogen fuel from a main fuel conduit, a burner configured to burn the portion of hydrogen fuel diverted from the main fuel conduit, a heat exchanger configured to transfer heat from exhaust gasses produced by the burner to hydrogen fuel in the main fuel conduit and a power recovery device configured to extract power from exhaust gasses of the burner downstream of the heat-exchanger.

Abstract: A sensor assembly is shown for sensing a crossing of the critical point in a system utilising a working fluid in a transcritical cycle passing through the critical point. A first broadband acoustic sensor is located upstream of a component and a second broadband acoustic sensor is located downstream of the component, each of which are arranged to detect high-frequency and low-frequency sounds caused by the crossing of the critical point. A flow regulation device regulates flow of working fluid through the component in response to the output of one or both of the first broadband acoustic sensor and the second broadband acoustic sensor, thereby adjusting the location of the crossing of the critical point.

Abstract: A fuel delivery system for a gas turbine engine comprises a cryogenic fuel tank, a first fuel line for connection to the cryogenic fuel tank, a fuel pump connected to receive fuel via the first fuel line, a plurality of fuel lines connecting the fuel pump to a combustor of the gas turbine engine, a controller configured to operate the fuel delivery system, a purge gas tank connected to the first fuel line and configured to store a purge gas for purging the plurality of fuel lines and a fuel gas tank connected to the first fuel line and configured to store a fuel gas for flushing purge gas from the plurality of fuel lines.

Abstract: A combined cycle engine is formed of a gas turbine cycle coupled with a fuel expansion cycle in which fuel for the gas turbine cycle is the working fluid of the fuel expansion cycle. The fuel expansion cycle comprises, in flow series, a fuel pump for pumping a cryogenic fuel for the gas turbine cycle, a first heat exchanger for heating the fuel, an expander to recover power by expansion of the fuel and to thereby drive a load, and a second heat exchanger to reheat the fuel. The gas turbine cycle comprises, in flow series, a compressor, a combustor for combustion of reheated fuel delivered from the second heat exchanger, and a turbine configured to drive the compressor. The first heat exchanger and the second heat exchanger are stationed downstream of the combustor and configured to transfer heat from combustion products to the fuel in the fuel expansion cycle.

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 sensor assembly is shown for sensing a crossing of the critical point in a system utilising a working fluid in a transcritical cycle passing through the critical point. A first broadband acoustic sensor is located upstream of a component and a second broadband acoustic sensor is located downstream of the component, each of which are arranged to detect high-frequency and low-frequency sounds caused by the crossing of the critical point. A flow regulation device regulates flow of working fluid through the component in response to the output of one or both of the first broadband acoustic sensor and the second broadband acoustic sensor, thereby adjusting the location of the crossing of the critical point.

Abstract: A fluid pump is shown, comprising: a chamber comprising an inlet and an outlet, the outlet comprising a non-return valve, the chamber having a cavity comprising a cylinder; a piston slidably disposed within the cylinder; and a Tesla valve in fluid communication with the inlet, wherein the fluid pump is configured to pump fluid from the inlet to the outlet by reciprocation of the piston within the cylinder.

Abstract: A fuel delivery system for a gas turbine engine comprises a cryogenic fuel tank, a first fuel line for connection to the cryogenic fuel tank, a fuel pump connected to receive fuel via the first fuel line, a plurality of fuel lines connecting the fuel pump to a combustor of the gas turbine engine, a controller configured to operate the fuel delivery system, a purge gas tank connected to the first fuel line and configured to store a purge gas for purging the plurality of fuel lines and a fuel gas tank connected to the first fuel line and configured to store a fuel gas for flushing purge gas from the plurality of fuel lines.

Abstract: A centrifugal compressor is shown, comprising: an impeller; a rotatably mounted diffuser surrounding the impeller; and a driving arrangement configured to drive the impeller and diffuser to rotate in opposing directions.

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: A trans-critical thermodynamic system includes an expansion device and a separator. The expansion device receives a supercritical fluid containing solutes. The expansion device is operable to expand the supercritical fluid to produce a sub-critical gas by reducing a temperature and/or a pressure of the supercritical fluid. The separator removes the solutes from the sub-critical gas.

Abstract: A hydrogen storage tank has a composite laminate wall, a hydrogen-porous layer in contact with the outer surface of the composite laminate wall and a hydrogen-non-porous layer in contact with the outer surface of the hydrogen-porous layer, the hydrogen-non-porous layer having an output port for venting hydrogen which passes through the composite laminate wall and the hydrogen-porous layer from the interior of the tank. The tank allows hydrogen which leaks through the composite laminate wall to be collected and re-used. The invention also allows for the rate of hydrogen leakage from the tank to be measured, providing a measure of the structural integrity of the tank.

Abstract: A fuel delivery system (201) is shown for delivering the hydrogen fuel from a cryogenic storage system to a fuel injection system in a gas turbine engine. The fuel delivery system includes a pump (301), a metering device (302), and a fuel heating system (303,304) for heating the hydrogen fuel to an injection temperature for the fuel injection system.

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 hydrogen fuel vaporiser (218) is shown for vaporising cryogenically-stored hydrogen fuel prior to injection into a gas turbine engine. The vaporiser (218) comprises a fuel offtake (301) configured and arranged to divert a portion of hydrogen fuel from a main fuel conduit (217), a burner (303) configured and arranged to burn the portion of hydrogen fuel diverted from the main fuel conduit (217), and a heat exchanger configured and arranged to transfer heat produced by the burner to hydrogen fuel in the main fuel conduit (217).

Abstract: A complex cycle gas turbine engine (103) for an aircraft with hydrogen fuel supply. The gas turbine engine comprises, in fluid flow series, a core gas turbine (105) and a recuperator (701) for heating hydrogen fuel prior to combustion by turbine exhaust products.

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: 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.