Thermo-hydraulic performance analysis of a staggered-flow Z-type manifold microchannel heat sink for ultra-high heat flux thermal management

In this study, we present a novel design for a staggered-flow Z-type manifold microchannel heat sink (Z-MMHS). The primary mechanism involves the staggered configuration of Z-type main channels and branch microchannels, which promotes periodic cross-flow and redistribution of the coolant. This arrangement induces localized secondary vortices at the inlet of each microchannel segment, effectively disrupting thermal boundary layers and enhancing wall heat transfer. Additionally, the manifold structure facilitates alternating flow divergence and convergence, thereby preventing the formation of dead zones and backflow often encountered in conventional straight microchannels. This ensures uniform flow distribution and consistent thermal resistance across the entire device.Using computational fluid dynamics (CFD) simulations, we systematically investigated the effects of different pin–fin cross-sectional geometries (circular, triangular, square, and trapezoidal) on secondary flow intensity and pressure drop characteristics. We also examined the coupled influence of inlet velocity, fluid temperature, and pulsed wall heat flux on the underlying heat transfer mechanisms.Entropy generation analysis revealed that the staggered-flow configuration achieves an optimal balance between inertial enhancement and viscous dissipation. A moderate increase in inlet velocity enhances secondary vortex formation and reduces thermal irreversibility, whereas excessive velocity results in increased pressure loss and total entropy generation. Elevated inlet temperatures and heat fluxes reduce fluid viscosity, thereby decreasing viscous dissipation and enhancing vortex-induced turbulent diffusion. The optimized Z-MMHS demonstrated low thermal resistance and acceptable pressure drop under pulsed heat flux conditions. Compared with conventional straight microchannel designs, it exhibited significant improvements in thermal performance, underscoring its strong potential for thermal management in high-power semiconductor applications.