ABSTRACT
Many important technological applications involve phase change that is, freezing and melting such as the solidification of metals or plastics in casting and coating processes, welding, high-energy laser beam cutting and forming, crystal growth, freezing or thawing of foodstuffs, ice production, aerodynamic ablation, and thermal energy storage using solid-liquid phase-changing materials to name just a few. There are also important medical applications that involve phase change such as cryosurgery or organ preservation. Heat conduction problems in which phase change occurs are generally referred to as moving boundary problems. Such problems are inherently transient because the location of the interface between the two phase's changes with time as latent heat is absorbed or released at the interface. In the solidification or melting of pure substances, such as water or pure metals, and eutectic alloys, the phase change takes place at a fixed temperature (i.e., fusion temperature), and there is a sharp moving interface between the two phases.
