An improved layered thermal resistance model for solid-liquid phase change time estimation

Abstract

This work improves a layered thermal resistance (LTR) model for the prediction of phase change times in solid-liquid phase change heat transfer. A combination of analytical and numerical approaches is applied in 1-D and 2-D solidification problems where heat conduction is dominant. In the improved layered thermal resistance (ILTR) model, the domain is discretized to layers. Based on its thermal resistance, the solidification time of each discrete layer is obtained by calculating the heat flux across the boundaries and the sensible and latent heat transfer. Unlike the quasi-steady heat conduction approach and linear temperature distribution assumption in the LTR model, the ILTR model considers transient heat conduction in each layer thus providing a better estimation of the average temperature distribution. The total solidification time is obtained by adding the solidification time of all the discrete layers. In several validations, the ILTR model shows a good agreement with the exact solution (1-D), experimental results (1-D), and numerical results (2-D). It is demonstrated that the ILTR model provides better predictions of phase change times than the LTR model, particularly under large Stefan numbers. This model could be further developed for more complicated (geometry or boundary conditions) phase change problems.