Thermal–Hydraulic Performance Analysis of Micro Pin‐Fin Heat Sinks With Different Fin Geometries: A Numerical Study

Efficient thermal management is essential for maintaining the reliability and performance of modern microelectronic devices. This study presents a detailed numerical analysis of a three‐dimensional micro pin fin heat sink incorporating 55 fins arranged in a single channel with four distinct cross‐sectional geometries: square, circular, triangular, and pentagonal. A conventional microchannel heat sink (MCHS) without pin fins is used as a baseline for comparison. Water is employed as the working fluid, and simulations are conducted under laminar flow conditions with Reynolds numbers ( Re ) ranging from 500 to 1500. To efficiently capture thermo‐hydrodynamic behavior while reducing computational cost, a representative single flow channel is modeled using symmetrical boundary conditions. Key geometric parameters, including pin fin height and spacing, are systematically varied while maintaining constant hydraulic diameter and spacing across all cases. Non‐dimensional spacing ratios ( s p /h p ) are adjusted to evaluate their influence on heat sink performance. The results indicate that among all geometries, circular fins provide the highest heat transfer enhancement, with the Nusselt number increasing by approximately 60% at Re = 500 and up to 90% at Re = 1500 compared to the baseline case. However, this improvement is accompanied by a relatively higher pressure drop. Triangular and square fin configurations show moderate heat transfer enhancement, whereas pentagonal fins exhibit the least improvement. Additionally, heat transfer consistently increases with Reynolds number for all configurations. Overall, the study provides quantitative insights into the role of fin geometry and arrangement on thermal and fluid dynamic performance, offering useful guidelines for designing efficient micro pin fin heat sinks for microelectronic cooling applications.