Effects of density change and natural convection on the solidification process of a pure metal

The solidification of an initially superheated metal within a rectangular enclosure is studied numerically through the front-Bring method accounting for the solid-liquid density change and natural convection in the melt. The investigation focuses on the influence of both the volume contraction caused by solid-liquid density change and the natural convection effect in the melt. Difficulties associated with the complex time-dependent solid and liquid domains, the shapes of which are also a part of the solutions, are overcome by employing the boundary-fitted coordinate system. The computed results are validated and are shown in the forms of the transient position of the interface, the temperature distribution, the flow pattern, the Nusselt number and the solidification fraction, with respect to time. (C) 1997 Elsevier Science S.A.