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

Claim 13:
14. A propulsion system for an aircraft comprising:
a gas turbine engine comprising:
a combustor arranged to combust a fuel and having an exit, and wherein a combustor exit temperature—T40—is defined as an average temperature of flow 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 temperature—T41—is defined as an average temperature of flow at the leading edge of the rotor of the turbine at the cruise conditions; and
a compressor having an exit, wherein a compressor exit temperature—T30—is defined as an average temperature of flow at the exit from the compressor at the cruise conditions;

a fuel tank arranged to contain the fuel to power the gas turbine engine; and
a processor programmed to:
change the fuel supplied to the gas turbine engine;
receive data corresponding to a change in at least one of T30, T40 and T41; and
determine at least one fuel characteristic of the fuel based on the change in the at least one temperature, the at least one fuel characteristic comprising 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.