# US 12,601,291 B2 · Hydrogen fuelled gas turbine engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,601,291 B2 - Document ID: US12601291B2 - Status: Granted - Kind: B2 - Application number: 18/983,655 - Filed: 2024-12-17 - Published: 2025-07-17 - Granted: 2026-04-14 - Earliest claimed: 2024-01-17 - Assignees: ROLLS-ROYCE plc - Applicants: ROLLS-ROYCE plc - Inventors: Marko Bacic; Rory D. Stieger; Mark D. Taylor; Chloe J. Palmer; Kenneth J. Young - Web page: https://patentgrep.com/patent/US12601291B2 ## CPC - F02C 3/22: the fuel or oxidant being gaseous at standard temperature and pressure (F02C3/28 takes precedence) - F02C 7/22: Fuel supply systems - F02C 9/40: specially adapted to the use of a special fuel or a plurality of fuels - F23R 3/28: characterised by the fuel supply (burners F23D) - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - F23R: GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS (fluidised bed combustion apparatus specially adapted for operation at superatmospheric pressures F23C10/16) ## Abstract A fuel system for a gas turbine engine configured to combust hydrogen fuel is disclosed. The fuel system comprises a main fuel conduit and a fuel pump configured to operate on liquid hydrogen within the fuel conduit to provide pressurised fuel to a combustor of the gas turbine engine. A fuel metering unit is configured to control fuel flow delivered to the combustor. The fuel pump is configured to provide hydrogen at an outlet above a critical temperature and pressure, to thereby provide supercritical hydrogen fuel downstream. The fuel metering unit is configured to provide a variable flow area downstream of the pump, to deliver fuel at required flow parameters. ## Claims ### Claim 1 A fuel system for a gas turbine engine configured to combust hydrogen fuel, the fuel system comprising: a main fuel conduit; a fuel pump configured to operate on liquid hydrogen within the fuel conduit to provide pressurised fuel to a combustor of the gas turbine engine; a fuel metering unit configured to control fuel flow delivered to the combustor; a controller configured to control the fuel pump and the fuel metering unit wherein the fuel pump is configured to provide hydrogen at an outlet above a critical temperature and pressure, to thereby provide supercritical hydrogen fuel downstream; the fuel metering unit is configured to provide a variable flow area downstream of the pump, to deliver fuel at required flow parameters; the controller is configured to control the fuel metering unit in accordance with a schedule in accordance with a fuel mass-flow demand setpoint; and the schedule comprises inputs comprising the fuel mass-flow demand setpoint, static pressure upstream and downstream of the fuel metering unit, and temperature upstream of the fuel metering unit, and an output comprising a valve position setpoint. ### Claim 2 (depends on 1) The fuel system according to claim 1, wherein critical temperature is greater than or equal to 33 Kelvin (K). ### Claim 3 (depends on 1) The fuel system according to claim 1, wherein the critical pressure is greater than 13 Bar. ### Claim 4 (depends on 1) The fuel system according to claim 1, wherein the fuel metering unit comprises a throttle valve configured to provide a variable pressure reduction between an inlet and an outlet. ### Claim 5 (depends on 1) The fuel system according to claim 1, wherein the fuel system is configured to provide a maximum pre-combusted fuel enthalpy at the outlet of the fuel pump. ### Claim 6 (depends on 1) The fuel system according to claim 1, wherein the fuel metering unit comprises one of a globe valve and a cone valve. ### Claim 7 (depends on 1) The fuel system according to claim 1, wherein the fuel metering unit comprises a plurality of throttle valves. ### Claim 8 (depends on 7) The fuel system according to claim 7, wherein the fuel system comprises a plurality of fuel injector passages coupled to the fuel conduit via a fuel manifold. ### Claim 9 (depends on 8) The fuel system according to claim 8, wherein each fuel injector passage comprise a respective throttle valve. ### Claim 10 (depends on 1) The fuel system according to claim 1, wherein the controller is configured to control the pump and fuel metering unit to provide a target fuel pressure and temperature, which target fuel temperature and pressure is above a critical temperature and pressure, and varies in accordance with a schedule set in accordance with a fuel flow demand set point. ### Claim 11 (depends on 10) The fuel system according to claim 10, wherein the controller is configured to control the pump to provide a pressure to the fuel metering unit sufficient to allow for a required fuel flow and pressure at the combustor. ### Claim 12 (depends on 1) The fuel system according to claim 1, wherein the fuel system comprise a fuel storage unit configured to store liquid hydrogen at a temperature of less than 30 Kelvin (K), and may be configured to store hydrogen at a temperature less than 25K, and may be configured to store hydrogen at a pressure of between 1 and 4 Bar. ### Claim 13 (depends on 1) The fuel system according to claim 1, wherein the fuel pump is configured to provide a maximum absolute pressure of between 13 Bar and 150 Bar. ### Claim 14 (depends on 1) A gas turbine engine comprising a fuel system according to claim 1. ### Claim 15 (depends on 1) A method of operating a fuel system according to claim 1, the method comprising: providing liquid hydrogen at an inlet to the fuel pump; controlling, by a controller of the fuel system, the fuel pump to provide supercritical fuel at an output of the fuel pump; and controlling, by the controller, the fuel metering unit to provide a required pressure and mass-flow rate to a gas turbine engine combustor of the gas turbine engine.