Research on the non-eutectic phase-change dynamics with heat transfer and component diffusion

The problem of phase-changing with heat and mass transfer has aroused widespread interest and imposed new challenges, especially in understanding the non-eutectic phase-change dynamics. In this paper, experimental study and model development were performed to analyze the crust solidification/melting dynamics with heat transfer and component diffusion, which played an important role in estimating the interface temperature and corresponding heat transfer. The experiments were performed with non-eutectic binary mixture of NaNO₃-KNO₃ as corium simulant during three heating power stages. Then the transient model was developed to describe crust formation and melting with both heat balance of corium pool and crust, as well as the mass balance at crust interface. Besides, the radiation and natural convection in top space, as well as heat conduction in the crust, gap and wall were taken into consideration. The developed transient model was validated against with experimental data and were proved to be in good agreement with each other. Furthermore, the parameters of crust-wall gap size and diffusive boundary layer thickness were performed for sensitivity study.