Correlation for the fin Nusselt number of natural convective heat sinks with vertically oriented plate-fins

In this paper, a correlation for estimating the fin Nusselt number of natural convective heat sinks with vertically oriented plate-fins is suggested. For this purpose, extensive experimental investigations are performed for various channel widths, heights and input powers. A numerical simulation is conducted by using a commercial tool to verify the present experimental results and examine fluid flow and heat transfer characteristics of a natural convective heat sink. By comparison of the present study and the previous studies, it is shown that the present correlation is widely applicable for Elenbaas numbers between 0.5 and 2 × 10⁶ and is more accurate than previous correlations. Based on an asymptotic approach, it is found that the optimal channel width is independent of the heat sink height but dependent of the heat sink length, the difference between the heat sink base and the ambient temperatures, and fluid property.