US 11,988,144 B2
Fuel viscosity
Craig W Bemment, Derby (GB); Alastair G Hobday, Derby (GB); Benjamin J Keeler, Chesterfield (GB); Christopher P Madden, Derby (GB); Andrea Minelli, Derby (GB); Andrew T Smith, Derby (GB); Peter Swann, Derby (GB); and Martin K Yates, Derby (GB)
Assigned to ROLLS-ROYCE plc, London (GB)
Filed by ROLLS-ROYCE plc, London (GB)
Filed on Jun. 20, 2023, as Appl. No. 18/337,516.
Claims priority of application No. 2219425 (GB), filed on Dec. 21, 2022.
Prior Publication US 2023/0332543 A1, Oct. 19, 2023
Int. Cl. F02C 7/14 (2006.01); F02C 7/224 (2006.01); F02C 7/36 (2006.01)
CPC F02C 7/14 (2013.01) [F02C 7/224 (2013.01); F02C 7/36 (2013.01); F05D 2220/323 (2013.01); F05D 2260/213 (2013.01)] 18 Claims
OG exemplary drawing
 
12. A gas turbine engine for an aircraft comprising:
an engine core comprising a turbine, a compressor, a combustor arranged to combust a fuel, and a core shaft connecting the turbine to the compressor;
a fan located upstream of the engine core, the fan comprising a plurality of fan blades;
a gearbox that is arranged to receive an input from the core shaft and output drive to the fan so as to drive the fan at a lower rotational speed than the core shaft;
a primary oil loop system arranged to supply oil to the gearbox;
a heat exchange system comprising:
an air-oil heat exchanger through which oil in the primary oil loop system flows;
a fuel-oil heat exchanger through which the oil in the primary oil loop system and the fuel flow such that heat is transferred between the oil and the fuel, and wherein the primary oil loop system branches such that a proportion of the oil can flow along each branch and the air-oil and fuel-oil heat exchangers are arranged in a parallel configuration on different branches of the primary oil loop system; and
a modulation valve arranged to allow the proportion of oil sent via each branch to be varied;
an integrated drive generator; and
a secondary oil loop system arranged to provide oil to the integrated drive generator, wherein:
the heat exchange system is arranged to adjust the fuel viscosity to a maximum of 0.58 mm2/s on entry to the combustor at cruise conditions, and
the heat exchange system further comprises a secondary fuel-oil heat exchanger arranged to receive oil from the secondary oil loop system, wherein the secondary fuel-oil heat exchanger is arranged to transfer heat between the oil from the secondary oil loop system and the fuel with the secondary fuel-oil heat exchanger.