Truss type lattice structures are regarded as a promising approach to design compact heat exchangers that are characterized also by good mechanical performances. The design of these structures can be tailored to satisfy multifunctional requirements and manufactured by exploiting the capabilities of additive manufacturing. This study reports on the experimental characterization of the aerothermal behaviour of new Body-Centred Cubic (BCC) lattice stagger arrays in a rectangular channel, which differ by the truss diameter. The heat exchangers are made from AlSi10Mg by means of Laser Powder Bed Fusion, and the geometric conformity and surface roughness of the internal features were characterized through optical and non-destructive methods to precisely define the boundary conditions at which the aero-thermal performances are provided. By so doing, some marginal defects caused by inherent limitations of the technology were observed, and relevant information in the perspective of designing new structures on a smaller characteristic scale were collected. The samples were then tested on a dedicated test rig by applying uniform heat flux boundary conditions up to a Reynolds number of 20′000. The experimental rig and methodology were firstly tested on a smooth channel and the results were found to be consistent with the literature. The BCC structure with the largest diameter performs the best in terms of heat transfer in view of the higher wetted surface. On the other hand, as expected, the friction factor shows the opposite trend. However, the thermal performance factor does not differ much among the different configurations, with slightly better performances observed for the larger diameter truss. Finally, correlations were found to predict both aero and thermal performances of the considered structure by introducing a modified formulation for the friction factor, Nusselt and Reynolds numbers.
