Patent ID: 11859565
Assignee: ROLLS-ROYCE PLC
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 8:
9. A method of determining at least one characteristic of a fuel provided to a gas turbine engine of an aircraft, the gas turbine engine forming part of a propulsion system and comprising:
a combustor arranged to combust the fuel and having an exit, and wherein a combustor exit pressure—P40—is defined as the total pressure at the combustor exit at cruise conditions;
a turbine comprising a rotor having a leading edge and a trailing edge, and wherein a turbine rotor entry pressure—P41—is defined as the total pressure at the leading edge of the rotor of the turbine at the cruise conditions; and
a compressor having an exit, wherein a compressor exit pressure—P30—is defined as the total pressure at the exit from the compressor at the cruise conditions;, wherein the method comprises:
changing the fuel supplied to the gas turbine engine; and
determining the at least one fuel characteristic of the fuel based on a change in at least one of P30, P40 and P41,, wherein the at least one fuel characteristic comprises at least one of:
i. a percentage of sustainable aviation fuel in the fuel; and
ii. an indication that the fuel is a fossil fuel.