KNO₃ 熔盐复合相变材料储热性能调控机理研究

In this paper, SWCNT with excellent thermophysical properties is doped into KNO₃ molten salt, and a microphysical model of KNO₃-SWCNT molten salt composite PCM is constructed. Molecular dynamics simulations were conducted on the thermal storage performance of KNO₃-SWCNT molten salt composite PCM, and the microstructure parameters and thermal storage performance parameters of the molten salt composite PCM are calculated, the surface charge modification of SWCNT method was used to control the thermal storage performance of molten salt composite PCM, and the micro mechanism of thermal storage performance control was revealed. It is found that with the increase of SWCNT mass fraction f_m, the thermal conductivity of molten salt composite PCM increase, and the viscosity, melting enthalpy, and melting point decrease. With the increase of temperature, the thermal conductivity and viscosity decrease; When f_m increases from 0 to 4.43% and 8.48%, the average thermal conductivity was increased by 2.26% and 28.01%, and the melting enthalpy decreases by 32.31% and 45.19%, respectively. The surface positive modification of SWCNT can change the microstructure of the molten salt composite PCM, so that the potential energy of interaction between atoms was enhanced, and effectively regulate the thermal storage performance of the molten salt PCM. The thermal conductivity of the molten salt composite PCM can be increased by 21.21% on average.