Temperature changes around interface cells in a one-dimensional Stefan condensation problem using four well-known phase-change models

Abstract

Discontinuous changes in thermodynamic properties across a very thin-phase interface and irregular deformations in the interfacial shape are accompanied by phase changes. Therefore, to simulate the phase-change phenomenon with a finite-sized mesh system is very challenging. Various numerical phase-change models have been developed, and several of them have been embedded in commercial computational fluid dynamics codes. However, the temperature reproducibility has not been dealt with carefully. In this study, we focused on the fact that most of the numerical phase-change models treat phase changes from a volumetric perspective, even though the phase change is definitely an interfacial phenomenon. We solved the one-dimensional (1D) Stefan condensation problem using four well-known numerical phase-change models (two temperature-difference phase-change models and two heat-flux phase-change models). Since the 1D Stefan problem has no convective effects, it is appropriate for investigating the inherent features of models exclusively. The temperature changes and interface movement with time were compared according to the applied phase-change model. Non-physical stepwise temperature changes over time were observed in models based on a volumetric perspective. The error analysis for different grid and time-step sizes was presented for the four different phase-change models.