a b s t r a c t
Convective heat transfer performances of high temperature molten salt in a vertical annular duct with
cooled wall were experimentally investigated within the range of Reynolds number 3000e16,000,
Prandtl number 4.8e7.6, and fluid temperature 300e400 C, respectively. The results showed that
Nusselt number of molten salt flow in annular duct was remarkably higher than that of circular tube, and
it increased with Reynolds number and Prandtl number. Because of variable thermal properties and
annular configuration, the heat transfer correlation for fully developed turbulent flow was proposed
based on Wiegand correlation and SiedereTate correlation, while the heat transfer correlation for
transition flow was established by Gnielinski equation and Wiegand equation. Based on the experimental
data, the modified heat transfer correlations for molten salt flow in annular duct were developed by
least-squares method, and the modified correlations for transition and turbulent flow had good agreement
with experimental data.