Enhanced natural convection heat transfer of a chimney-based radial heat sink

In this study, the natural convection heat transfer from chimney-based radial heat sinks was investigated numerically and experimentally. The thermal performance of a radial heat sink with chimney was estimated and compared with that of a radial heat sink without a chimney. The effects on the heat sinks' thermal performance were investigated in regard to the orientation angle with respect to gravity (0° ⩽ θ ⩽ 180°), the fin number (15 ⩽ N ⩽ 30), and the distance between the base plate and chimney (5 mm ⩽ Hc ⩽ 25 mm). The results show that there exist optimal values for Hc and N. The orientation angles 0° and 45° result in slightly better thermal performance than 135° and 180°, while 90° results in the worst thermal performance. The chimney-based heat sink with optimal structure enhances the thermal performance by up to 20% compared with the radial heat sink without a chimney.