Experimental Investigation of the Hydraulic Characteristics and Forced-Convection Thermal Performance of Porous Copper Alloy Fins: Effects of Airflow Velocity, Pore Density, and Porosity

Porous metallic fins have emerged as a promising alternative to conventional solid extended surfaces because their interconnected pore networks permit fluid penetration and offer a substantially larger effective heat transfer area. The present study reports a systematic experimental investigation of the hydraulic and thermal characteristics of porous copper alloy fins under forced convection. Eight sintered porous copper alloy specimens with pore densities of 10, 20, and 40 PPI, porosities ranging from 0.379 to 0.624, and thicknesses of 5 mm and 10 mm were tested in a controlled wind-tunnel facility over superficial air velocities of approximately 0.7–5.7 m/s.

Two objectives were pursued: (i) quantification of the influence of airflow velocity on pressure drop, permeability, inertia coefficient, and friction factor; and (ii) evaluation of the forced-convection heat transfer performance in terms of the convective heat transfer coefficient. The measured pressure drop increased nonlinearly with velocity in accordance with the Darcy–Forchheimer model, and rose with increasing pore density, decreasing porosity, and increasing specimen thickness, with pressure losses spanning approximately 20–970 Pa across the tested conditions. The experimentally determined permeability varied from 0.59 × 10⁻⁸ m² to 8.30 × 10⁻⁸ m² and behaved as an intrinsic structural property, decreasing with pore density and with reducing porosity, while the inertia coefficient increased with pore density and decreasing porosity and was only weakly sensitive to velocity.

The friction factor decreased monotonically with the permeability-based Reynolds number (ReK ≈ 4–112), reflecting the transition from viscous- to inertia-dominated transport. The convective heat transfer coefficient increased continuously with airflow velocity and with pore density, the 40 PPI specimen delivering the highest thermal performance, whereas porosity exhibited a competing influence between airflow penetration and solid-phase conduction, indicating the existence of an optimum void fraction.

The combined results demonstrate a clear thermo-hydraulic trade-off and provide experimentally validated permeability and inertia-coefficient data suitable for porous-media modelling and the design of compact heat sinks, electronics cooling modules, and battery thermal management systems.