Numerical study on convective heat transfer and friction characteristics of molten salts in circular tubes

Molten salts including fluoride, nitrate, chloride, and carbonate salts have been proposed for heat -transfer and thermal energy storage applications due to their superior thermal performance at elevated temperatures. Since it is expensive to perform molten salt heat transfer experiments due to the high working temperatures, a numerical analysis is carried out to investigate thermal and hydrodynamic performance of molten salts using a Computational Fluid Dynamics (CFD) tool, STAR-CCM+, and validate the numerical model using existing experimental data and convective heat transfer correlations, including Dittus-Boelter, Gnielinski, Hausen, and Sieder-Tate correlations. The analysis shows the hydrodynamic and thermal performance, such as the hydrodynamic/thermal entrance length, friction factor, and Nusselt number of molten salts in laminar and turbulent flow regimes can be appropriately modeled. In addition, the widely used convective heat transfer correlations provide good predictions for molten salt heat transfer.