Thermo-hydraulic performance of a Shark-skin-inspired finned microchannel heat sink with Görtler-type secondary flow enhancement

The ever-increasing heat flux of high-power-density integrated circuits poses critical thermal management challenges beyond capabilities of conventional rectangular-finned microchannel heat sinks (MCHSs). Here we propose a bio-inspired design that mimics the hierarchical micro- and macro-structures of shark skin, integrating its streamlined morphology and drag reducing characteristics into novel fin configurations. High-fidelity numerical simulations of turbulent flow and heat transfer are performed for full-scale MCHSs using the realizable k–ε model, which proves most suitable for capturing complex secondary flows induced by the highly curved surfaces of the bionic fins. Unlike conventional designs that trade enhanced heat transfer for a higher pressure drop, the present bionic fins successfully break this trade-off. Across the entire range of Reynolds numbers investigated, the flow resistance is consistently reduced by 26–35% compared with rectangular fins of identical volume for 5 and 8 mm fin configurations. Notably, when the Reynolds number exceeds approximately 2130, the heat transfer efficiency begins to increase, reaching a maximum enhancement of 16%. Under such conditions, the performance evaluation criterion relative to rectangular fins gradually rises to a peak value of 31%. High resolution flow field analysis reveals the underlying mechanism: the tapered trailing edges of the bionic fins generate powerful longitudinal vortices, which manifest as typical Görtler-type secondary flows, that substantially improve thermal mixing. Furthermore, a unique U-shaped temperature gradient is observed in the staggered bionic fin configuration, which promotes superior fluid and thermal uniformity across the heat source. This work provides a promising solution for thermal management of next-generation electronic devices.