AN IMPROVED TURBOFAN GAS TURBINE ENGINE

A turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, an inlet duct, 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 transfer elements for transfer of heat from a first fluid contained within the heat transfer elements to an airflow passing over a surface of the heat transfer elements prior to entry of the airflow into the fan assembly. [0002] In use, the first fluid has a maximum temperature of 80°C, and the heat exchanger module transfers at least 300kW of heat energy from the first fluid to the airflow.