Thermal performance of elliptical pin fin heat sink under combined natural and forced convection

• The input heat flux is having negligible influence on the thermal resistance of heat sink.
• The experimental results confirms the optimum fin spacing in terms of void fraction at α = 0.702.
• The optimum fin height in terms of aspect ratio, ϒϒ, is close to ϒ=8.2ϒ=8.2 for staggered arrangement.
• For inline arrangement, the influence of fin height is diminishing after aspect ratio, ϒ=8.16ϒ=8.16.
• The staggered arrangement is having better air side performance by 25–51% than inline arrangement.

In this paper, the effects of design parameters have been experimentally investigated for the air side thermal performance under mixed (combined natural and forced) convection of the fully shrouded elliptical pin fin heat sinks and the values of optimum design parameters are sought. A theoretical model is used to predict the influence of various geometrical, thermal and flow parameters on the thermal resistance of the heat sink. An experimental measurement technique is utilized to indirectly measure the overall heat transfer coefficient of the heat sink in mixed convection with assisting flow. The thermal performance characteristics are obtained for various parameters with inline and staggered layout of the pin fin heat sinks resulting in optimum heat sink void fraction (α  ), and pin fin aspect ratio (ϒϒ). The comparative thermal performances of circular and elliptical profiled pin fin heat sinks are presented. Based on experimental data for the range of fin, air flow and heat sink parameters, with aspect ratio, 5.1 ⩽ ϒϒ ⩽ 9.18; heat sink void fraction, 0.534 ⩽ α ⩽ 0.884; approach velocity, 0.1 ⩽ U∞ ⩽ 0.5; longitudinal fin pitch, 18 ⩽ SL ⩽ 36 mm; transverse fin pitch, 9 ⩽ ST ⩽ 18 mm; elliptical pin fin axis ratio ∊=0.66∊=0.66 and mixed convection parameter, 1 ⩽ Grd/Red ⩽ 100; generalized empirical correlations are developed for elliptical pin fin heat sink.