CPC F02C 7/224 (2013.01) [F23R 3/28 (2013.01); F05D 2260/20 (2013.01)] | 20 Claims |
1. A method of operating a gas turbine engine installed on an aircraft, the gas turbine engine comprising:
a fuel delivery system arranged to provide fuel;
a combustor arranged to combust the fuel;
a primary fuel-oil heat exchanger arranged to have 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, and 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 method comprises
operating the gas turbine engine while the aircraft is at cruise conditions, and
controlling the fuel delivery system, the primary fuel-oil heat exchanger and the secondary fuel-oil heat exchanger so as to transfer heat to the fuel from the oil in the primary fuel-oil heat exchanger in an amount between 200-600 KJ/m3 of heat per unit volume of fuel reaching the combustor when operating the gas turbine engine while the aircraft is operating at the cruise conditions.
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