Recalescence dynamics and solidification of a supercooled melt in a finite domain

摘要

We study the dynamics of supercooled solidification of a pure material in a finite domain subject to isothermal boundary conditions. At early stages when the liquid can effectively be treated as semi-infinite, we derive asymptotic solutions in the limits of both strong and weak latent-heat release, corresponding to large and small effective Stefan numbers, respectively. In particular, the solutions describing a rapid recalescence followed by a gradual change in the interfacial temperature are derived. Once the finite extent becomes effective, the system relaxes to an intermediate stage. For large Stefan numbers, the intermediate stage is quasi-steady, with the linear temperature profiles in the two phases and the interface temperature close to an equilibrium melting temperature. For Stefan numbers less than unity, the intermediate stage has a traveling-wave temperature profile in the liquid, similar to that in the one-sided problem, and a self-similar profile in the solid, where the temperature is close to the interface temperature through the whole solid except for a thermal boundary layer far from the interface. The model is applied to water, copper and salol, providing estimates for the freezing rates, interface position, and the recalescence and complete-freezing times in these pure systems.