Experimental investigation of heat transfer and pressure losses across additively manufactured Body Centered Cubic arrays: effects of cell shape and array arrangement

This study experimentally investigates the thermo-hydraulic performance of heat sinks featuring Body-Centered Cubic (BCC) lattices produced from AlSi10Mg via Laser Powder Bed Fusion. The objective is to assess the influence of key design parameters, such as truss inclination, lattice layout, and streamwise pitch on heat transfer and pressure drop characteristics. To this aim, the samples geometrical conformity and surface roughness were first characterized using optical and non-destructive methods, confirming good dimensional accuracy, although occasional surface defects caused by thermal distortion or dross formation were observed. Subsequently, tests were conducted on a dedicated test rig over Reynolds numbers ranging from 5000 to 27500, collecting pressure drop data under isothermal conditions and heat transfer data under uniform heat flux boundary conditions. The results showed that reducing the streamwise pitch improves thermal performance but also increases flow resistance. Conversely, staggered configurations reduce friction losses at the expenses of some heat transfer efficiency. Variations in truss inclination had instead minimal impact. The introduction of a modified hydraulic diameter quantifying the unit cell density, and the streamwise pitch parameter enabled a novel normalization method that successfully collapsed the performance data across all configurations. Finally, by evaluating the Thermal Performance Factor for each dataset, the study identified the optimal trade-off between friction losses and thermal performances among all tested geometries.