Optimization of Hollow Hybrid Fin Heat Sinks under Natural Convection

This study investigates the optimization method for hollow hybrid fin heat sinks (HHFHSs) under natural convection. The HHF is a hollow pin fin integrated with radial plate fins, and the HHFHS consists of the staggered array of HHFs and a horizontal base plate. The Nusselt number correlations for the HHF array were developed considering modified Rayleigh number, fin efficiency, and geometric parameters of the HHF. The optimization of the HHFHS was conducted by optimizing both the HHF and the fin spacing of the array. Least material method and Nusselt number correlations for the HHF array were used for the optimization. This study found that the optimal wall thickness of the HHF could be expressed as a function of fin volume and structural perimeters. It was also revealed that the optimal fin spacing would depend on the length of the base plate. The thermal performances of the optimized HHFHS and PFHS were compared at the fixed base area and a specific fin mass condition, respectively. The results have shown that the optimized HHFHS is superior to the optimized PFHS at a specific mass condition.