An Integrated Thermal and Mechanical Performance Analysis of Effect of Cold Molten Salt Temperature for Thermocline Tank

Abstract

To study the effect law of cold molten salt temperature on both the thermal energy storage and mechanical performances of a thermocline molten salt tank, a numerical model of the tank which includes a multi-layer wall is established. The tank wall consists of three layers, which are firebrick, steel, and ceramic, respectively. Fluent code is employed to carry out the simulations of five different complete operation cycles of the thermocline tank. An integrated thermal and mechanical performance analysis of the effect of cold molten salt temperature for the thermocline tank is carried out. The analysis results reveal that for all the simulated cases, the thermocline is steady, and both the charging and discharging processes of the tank are stable. The thermocline thickness of the charging process can be smaller than that of the discharging one. The axial temperature of steel wall does not change synchronously with the central axial temperature of molten salt during both charging and discharging processes. As the cold molten salt temperature decreases, the thermocline thickness as well as the maximum mechanical stress of the steel wall increases. Hence, it can be drawn that increasing the cold molten salt temperature properly will be of benefit to both the energy storage performance and stability of the thermocline tank structure.