Experimental investigation on the shell-side heat transfer performance of molten salt steam generator

摘要

In this study, an experiment was conducted to obtain the heat flux and heat transfer coefficient of a mixed molten salt (60% NaNO_3, 40% KNO_3) and water at subcritical pressure in a tube in tube heat exchanger. The control variable method was used in this study. The experimental parameters included the molten salt and water mass fluxes of 38.7-54.1 kg/m~2s and 212.8-259.6 kg/m~2s, respectively, water pressure of 15-19 MPa, water and molten salt inlet temperatures of 200-400 °C and 440-500 °C, respectively, and heat flux of 12-160 kW/m~2. The heat transfer performances of the molten salt and water in the sub-cooled, subcooled boiling, saturated boiling, dryout and superheated regions were analysed with respect to the molten salt and water mass flow rate, inlet salt temperature, water pressure, and inlet water temperature. The fitting correlation of the thermal performance of molten salt to the subcooled boiling or vapor-liquid two-phase flow was presented; the fitting values demonstrated good consistency with the experimental data, with a maximum deviation of -6% and +8%.