Orientation effects on the performance of natural convection cooled hybrid fins

This study reports orientation effects on the thermal performance of hybrid fins (HFs) under a natural convection state. HFs are either a hollow or a solid pin fin integrated with radially-placed plate fins. HFs have been proposed for the development of lightweight heat sinks for electronics and photonics cooling. We investigates orientation effects on both the area based performance and the mass based performance of a hollow hybrid fin (HHF) and a solid hybrid fin (SHF) by conducting 3D CFD analysis. The results show that both the area based and the mass based performances of the HHF and the SHF are better than those of pin fins (PFs). It is seen that the HHF performance is almost independent of the orientation contrary to the SHF and the PF. The orientation independence might be explained by the compensation between the decrease in the internal heat dissipation and the increase in the external heat dissipation for the increase in the declination angle.