Numerical Analysis of Single-Phase Heat Transfer on Micro Pin Fin Arrays for Liquid Electronic Cooling Applicatio

With miniaturization of electronic components, the need for heat dissipation becomes a crucial factor for system performance. Pin fin heat sinks with liquid cooling have become an effective choice for cooling microelectronic packages. A numerical study of heat transfer and pressure drop characteristics was performed over three staggered arrays of micro-pin fins for a single-phase laminar fluid flow condition. Three fins modeled were, circular, elliptical and hydrofoil having the same solid fraction and constant pitch to width ratio. A heat sink with 0.14 times 10 mm2 footprint was modeled choosing staggered hydrofoil array with 280mum chord length and 110mum foil thickness as the basis of comparison. Symmetry conditions were adopted parallel to the fluid flow and assumption is validated as the H/L ratio is less than 1 nullifying the effect of end walls on the modeled problem. Validating the numerical model over experimental results from literature, correlations were developed for Nusselt number and friction factor as a function of Reynolds number. The average Nusselt number for finned structure was found to be 2.5 to 3.5 times higher than the conventional parallel plate structure. Average heat transfer coefficient for hydrofoil and elliptical fin showed an improvement of 8.5% and 5.7% respectively over circular fin at high-pressure drop range. Average friction factor for hydrofoil and elliptical fins were 53% and 44% lower to circular fin respectively. Hydrofoil was concluded as the best configuration for thermal performance at a specific pressure drop and pumping power showing streamlined flow throughout the range of Reynolds number modeled.