Additive manufacturing is revolutionizing the production of thermo-fluidic devices by enabling the creation of a wide variety of complex architectures, significantly enhancing performance and efficiency. Nevertheless, the range of structural types investigated to date remains limited, with most studies employing simplified methodologies and constrained operating conditions. This study explores the thermo-hydraulic performance of water-cooled annular channels incorporating BCC, Octahedral, and gyroid structures fabricated from AISI 316L stainless steel using Laser Powder Bed Fusion. The samples were experimentally tested across a broad spectrum of mass flow rates using a custom-designed test rig to evaluate heat transfer and pressure loss performance, and extensive morphological characterization was conducted to correlate the thermo-fluid dynamic behavior with the geometric and surface features specific to the manufacturing process. The investigation revealed that reticular configurations are preferable when low pressure losses are required, whereas gyroids are more suitable for high thermal loads. The topology of the structures was shown to be a key factor influencing overall performance, emphasizing the importance of selecting the appropriate structure for each specific application and the significant potential for performance improvements through the development of tailored metamaterials.
