Moving solid-liquid interface-based measurement method for thermal conductivity determination of phase change materials in liquid phase

Abstract

In this study, we demonstrate a new method for determining the thermal conductivity of phase-change materials in the liquid phase. The primary idea behind the method is to incorporate the Stefan problem within the melting test, as this allows for the determination of the thermal conductivity based on the movement of the solid-liquid interface during the melting process. An analytical solution of a one-dimensional Stefan problem, which was used as the measurement model, was obtained using the Laplace transform, and the corresponding testing system was established. The underlying principle of the method was elucidated and its feasibility was evaluated through a series of experiments. The obtained results were found to be in good agreement with the literature data, with the measurement errors being limited to ±5%. These errors were caused by two factors: the imperfect implementation of the Stefan boundary and the onset of natural convection. However, their effects on the measurement results can be mitigated through appropriate operations. Compared with conventional methods, the proposed method is suitable for performing high-precision thermal conductivity measurements at low costs.