Synergistic hydro-thermal performance enhancement of micro pin-fin heat sinks via improved pitch angle, perforations, and flow steering mechanisms

• Spiral pin-fins significantly boost heat transfer over simple models. • Optimal pitch angle of 40° improves thermal performance by 22.7%. • Case A with perforations and tilt achieves 65% higher efficiency. • Maximum heat transfer coefficient of 4310 W/m 2 K recorded for Case A. • Combined flow steering and perforations outperform high-friction designs. This study presents a numerical investigation into the hydro-thermal performance of a novel water-cooled heat sink featuring cylindrical spiral pin-fins designed for high heat flux management. Using ANSYS Fluent, the research was conducted in two phases. The first phase systematically analyzed the effect of the spiral pitch angle ( θ ) and identified the θ = 40 ° configuration as the best geometry, yielding a Thermal Performance Factor (η) of 1.24 at Re = 500, representing a 24.0% improvement over the Simple Model ( θ = 0 ° ). In the second phase, various geometric modifications, including perforations and tilt angles, were applied to the optimal θ = 4 0 ° base model (Cases A-F). The results conclusively demonstrate that the combined modification featuring perforations and a 45 ° forward tilt (Case A) achieved the maximum performance. At Re = 2000, Case A attained a heat transfer coefficient (h) of approximately 8550 W / (m 2 . K ) , an enhancement of roughly 50.0% compared to the Simple Model. Furthermore, despite incurring the highest pressure penalty ( Δ P ), Case A maintained the highest overall effectiveness, recording a peak η value of approximately 1.65 at Re = 500, which translates to a substantial 65.0% improvement in thermal performance over the Simple Model. These findings provide critical design guidelines, establishing the 40 ° spiral pin–fin with perforations and forward tilt as a highly effective, ready-to-implement solution for next-generation compact thermal management systems.