US 12,421,915 B2
Fuel supply system
Benjamin J Keeler, Chesterfield (GB); Craig W Bemment, Derby (GB); Andrea Minelli, Derby (GB); Paul W Ferra, Derby (GB); Alastair G Hobday, Derby (GB); and Andrew T Smith, Derby (GB)
Assigned to ROLLS-ROYCE plc, London (GB)
Filed by ROLLS-ROYCE plc, London (GB)
Filed on Jun. 25, 2024, as Appl. No. 18/753,116.
Claims priority of application No. 2319156 (GB), filed on Dec. 14, 2023.
Prior Publication US 2025/0198365 A1, Jun. 19, 2025
Int. Cl. F02K 3/06 (2006.01); F02C 7/36 (2006.01); F02C 9/18 (2006.01)
CPC F02K 3/06 (2013.01) [F02C 7/36 (2013.01); F02C 9/18 (2013.01); F05D 2240/35 (2013.01); F05D 2260/213 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A gas turbine engine for an aircraft comprising:
an engine core comprising a turbine, a combustor, a compressor, and a core shaft connecting the turbine to the compressor;
a fan located upstream of the engine core and arranged to be driven by the core shaft, the fan comprising a plurality of fan blades;
a nacelle surrounding the fan and the engine core and defining a bypass duct located radially outside of the engine core, where a bypass ratio, defined as a ratio of a mass flow rate of a flow through the bypass duct to a mass flow rate of a flow through the engine core at cruise conditions, is at least 4;
a plurality of actuators;
a fuel supply system, wherein the fuel supply system is arranged to supply fuel for combustion in the combustor, and to supply fuel to fueldraulically drive at least one actuator of the plurality of actuators;
two fuel-oil heat exchangers arranged to have oil and the fuel flow therethrough, the heat exchangers being arranged to transfer heat from the oil to the fuel and comprising a primary fuel-oil heat exchanger arranged to heat at least a majority of the fuel, and a secondary fuel-oil heat exchanger arranged to provide additional heat to the fuel to be supplied to fueldraulically drive the at least one fueldraulic actuator;
a first fuel recirculation valve operable to enable fuel to recirculate through the primary heat exchanger;
a second fuel recirculation valve operable to enable fuel to recirculate through the secondary heat exchanger; and
a controller configured to control the first fuel recirculation valve and the second recirculation valve such that, under cruise conditions, a heat transfer ratio of:

OG Complex Work Unit Math
has a maximum value of at least 0.35.