Embedded micro-pin-fin heat sink with 3D manifold for cooling high-power electronics

The relentless increase in chip power density has driven heat fluxes beyond 1 kW cm −2 , urgently demanding effective and efficient thermal management. Although embedded manifold microfluidic cooling with micro-pin-fin (MPF) arrays has emerged as a promising strategy, the cross-scale impacts of the complex three-dimensional (3D) architecture on the thermohydraulic performance remain to be elucidated, together with the underlying physical mechanisms. In this study, we conduct a comprehensive 3D numerical investigation of embedded HU-type manifold MPF heat sinks. Using a hierarchical three-model strategy, we analyze the influence of key MPF geometric parameters and array layouts on the thermohydraulic performance. To begin with, we consider in-line and staggered arrays of circular MPFs and compare against a conventional microchannel (MC) baseline. Systematic analysis shows that increasing MPF diameter reduces the maximum chip temperature rise ( Δ T max ) while raising pressure drop ( Δ P ); conversely, increasing MPF height ( H f ) yields the opposite trade-off when the cavity height ( H cav ) of the microfluidic layer varies accordingly. With a fixed H cav , however, increasing H f reduces the top clearance, which suppresses bypass leakage and significantly enhances heat transfer. Further, transverse and longitudinal spacings highlight asymmetric cross-coupling effects. At large spacings, flow channeling circumvents MPFs through low-resistance pathways and creates wakes that severely degrade heat transfer. Moreover, by evaluating a variety of MPF cross-sections, we reveal that the diamond shape can outperform the MC baseline in both thermal and flow performance. At a heat flux of 2000 W cm −2 , diamond-shaped MPFs simultaneously achieve lower Δ T max (56 K) and Δ P (28 kPa), yielding a coefficient of performance exceeding 2000. These findings establish parametric design maps and mechanistic insights for optimizing manifold MPF heat sinks targeting high-power electronics.