Patent ID: 11920514
Assignee: ROLLS-ROYCE PLC
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 12:
13. A gas turbine engine for an aircraft, the gas turbine engine comprising:
a fuel delivery system that includes a pump and is arranged to provide fuel;
a combustor arranged to combust at least a proportion of the fuel; and
a plurality of heat exchangers comprising:
a primary fuel-oil heat exchanger arranged to have up to 100% of the fuel provided by the fuel delivery system flow therethrough; and
a secondary fuel-oil heat exchanger arranged to have a proportion of the fuel from the primary fuel-oil heat exchanger flow therethrough, wherein the proportion of the fuel is arranged to flow from the primary fuel-oil heat exchanger to the secondary fuel-oil heat exchanger and oil is arranged to flow from the secondary fuel-oil heat exchanger to the primary fuel-oil heat exchanger; and

wherein the plurality of heat exchangers is arranged to heat the fuel so as to adjust a fuel viscosity to a maximum of 0.58 mm2/s on entry to the combustor at cruise conditions.