Numerical and experimental analysis of thermo-aerodynamic performance in an aero engine surface heat exchanger

A surface air-cooled oil cooler (SACOC) is a passive heat exchanger used to evacuate a large quantity of heat from the oil circuit of a turbofan engine to its secondary flow with minimal perturbation. Using the secondary flow as a heat sink has the advantage of the evacuated enthalpy being available in the nozzle. The performance of a SACOC is therefore measured in terms of maximum heat release capacity with minimal pressure loss and flow perturbations. These heat exchangers are typically composed of parallel fins and are usually tested in bespoke wind tunnels where the interaction between the three-dimensional high velocity flow and the heat exchangers is evaluated. Modern numerical computations that include the solution of the fluid equations in the flow field and a conjugate thermal problem can be also performed. This numerical approach, once validated, allows a complete and computationally affordable analysis of the aero-thermodynamic performance of the SACOC. In this work, a first comparison between both experimental and computational perspectives is presented in terms of pressure and temperature profiles to achieve a complete characterization of the device. This double experimental numerical perspective allows comparing the behaviour of the different fins of the SACOC depending on their relative position but also to trust the numerical conclusions with experimental robust data.