US Patent 11773782 Gas turbine engines having cryogenic fuel systems

Turbine engine systems and aircraft having such systems are described. The turbine engine systems include a combustor arranged along a core flow path of the turbine engine, a drive shaft having at least a compressor section and a turbine section coupled thereto, a cryogenic fuel tank configured to supply a fuel to the combustor, and an expansion turbine mechanically coupled to the drive shaft, the expansion turbine configured to receive fuel from the cryogenic fuel tank and expand said fuel, wherein expansion of said fuel by the expansion turbine drives rotation of the expansion turbine to provide power input to the drive shaft.