Effects of groove geometry around pin-fin perforation circumference on thermohydraulic behavior of pin-fin heat sinks under turbulent flow

The thermohydraulic performance of perforated pin-fin heat sinks (PPFHS) with different groove geometries around pin-fin perforation circumference is numerically investigated using ANSYS Fluent under turbulent flow conditions with Reynolds numbers (Re) ranging from 24,484 to 55,088. Four groove geometries-trapezoid, half-circle, rectangle, and triangle-are assessed for their effects on convective heat transfer efficiency, hydraulic resistance, and overall thermohydraulic performance. The groove sizes are designed to maintain a consistent air-solid interfacial surface area to total volume ratio across all configurations. The study finds that the trapezoidgrooved PPFHS exhibits the highest Nusselt number (Nu), achieving improvements of 11.8 %- 20.9 % compared to the ungrooved PPFHS over the investigated Re range. The half-circle, rectangle, and triangle grooves show Nu enhancements of 10.9-20.2 %, 10.9-20.1 %, and 9.87-18.6 %, respectively. Friction factor reductions range from 4.35 to 8.57 %, 4.22-7.71 %, 3.10-6.62 %, and 0.87-5.05 % for the trapezoid, half-circle, rectangle, and triangle grooves, respectively. The thermal performance factor (TPF) of the trapezoid-grooved PPFHS is the highest, with improvements of 13.5-24.5 % over the ungrooved design, followed by the half-circle (12.5-23.4 %), rectangle (12.1-22.9 %), and triangle (10.2-20.7 %) grooves. While TPF increases with Re, a diminishing rate of enhancement is observed at higher Re. The superior performance of the trapezoid groove is attributed to its ability to promote the most efficient airflow through the perforations while maintaining the lowest perimeter-to-cross-sectional area ratio.