US Patent 12123351 Turbofan gas turbine engine

A turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, and a turbine module. The fan assembly comprises a plurality of fan blades defining a fan diameter (D), and the heat exchanger module comprises a plurality of heat exchanger elements. The heat exchanger module is in fluid communication with the fan assembly by an inlet duct, with the heat exchanger module having an axial length along a central axis between an upstream-most face of the heat exchanger elements and a downstream-most face of the heat exchanger elements. The axial length is in the range of 0.1*D to 5.0*D.