Patent ID: 11970975
Assignee: ROLLS-ROYCE PLC
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F  Y | IPC F

Claim 11:
12. A method of delivering hydrogen fuel from a cryogenic storage system to a fuel injection system in a gas turbine engine, comprising:
pumping the hydrogen fuel from the cryogenic storage system;
heating the hydrogen fuel to an injection temperature for the fuel injection system;
metering the quantity of fuel for delivery to the fuel injection system via a metering device,
wherein the heating comprises vaporising the hydrogen fuel from the cryogenic storage system,
the metering device is a sonic fixed orifice configured to operate in a choked condition and a flow rate is controlled by adjusting (i) an upstream pressure delivered by the pump based on a measured upstream temperature of the sonic fixed orifice and an area of the sonic fixed orifice, and (ii) a pressure ratio across the sonic fixed orifice,
the vaporising comprises diverting a portion of the hydrogen fuel from a fuel conduit through a fuel offtake for combustion in a burner located in heat exchange relationship with the fuel conduit, and
the burner is disposed concentrically around the fuel conduit.