This paper presents numerical simulation of solidification around a cooled circular cylinder with the presence of a free surface in a rectangular cavity. The free surface is introduced to account for volume change due to density difference between the solid and liquid phases during solidification. Pure tin with the solid-to-liquid density ratio sl = 1.05 (shrinkage) is investigated as a phase change material. The front-tracking method combined with an interpolation technique, in which the interface separating two phases is represented by connected elements laid on a stationary grid, is used for solving the problem. The case of no volume change, i.e., sl = 1.0, is also calculated and compared with the case of sl = 1.05 to see how volume shrinkage affects the solidification process. The numerical results show that shrinkage reduces the solidification rate, and thus results in a decrease in the form, i.e., the area, of the solid layer around the cylinder. In addition, the liquid level decreases in time due to volume shrinkage upon solidification.
