Synergistic design of bi-level heat sink combining topology-optimized microchannels with jet impingement for high-heat-flux applications

This study presents a bi-level heat sink designed through a manufacturing-aware framework that integrates macro-scale jet impingement manifolds with micro-scale topology-optimized channels. Prototypes were fabricated via laser powder bed fusion (LPBF) and examined using computed tomography (CT) to capture manufacturing-induced deviations. Coupled simulations and experiments evaluated three inlet–outlet configurations (2IN1OUT, 3IN2OUT, and 4IN5OUT, corresponding to two/one, three/two, and four/five inlet–outlet channel combinations, respectively) under high heat fluxes ranging from 83.3 to 200 W/cm². All designs achieved effective cooling, with the 4IN5OUT configuration delivering the best thermal performance in simulation, maintaining an average temperature of 51.3 °C, a peak of 54.0 °C, and a pressure drop of 31.0 kPa at 200 W/cm². CT analysis revealed that LPBF-induced imperfections, such as channel shrinkage and surface roughness, increased pressure drop by 8.8–30.9 % and explained the experimental–numerical temperature discrepancies of 7.2–16.8 %. The optimized 2IN1OUT design exhibited the smallest deviations, consistent with CT findings showing closer geometric fidelity. These results establish a robust design–fabrication–validation workflow that bridges digital optimization with realizable performance, offering a practical and scalable thermal management solution for next-generation high-power electronics.