A numerical investigation of a liquid bridge solidifying with volume change

Abstract

A liquid bridge with solidification appears in living nature and numerous technical applications. Volume change upon solidification can induce a remarkable difference in the final shape of the bridge. To better understanding this problem, we use a direct numerical simulation (DNS) approach to study the solidification process of the vertical liquid bridge. The bridge is held between two equal-sized coaxial disks (or rods) with the presence of vertical gravity and the density difference between the liquid and its corresponding solid phase of the bridge. The solidification starts from the stable shape of the DNS solution (using the same method) when the rod temperature is suddenly lowered to a value below the melting point of the bridge liquid. It is found that the upper and lower phase-change interfaces propagate at nearly the same speed, and a ring (or protrusion) is formed around the bridge at mid-plane after complete solidification because of volume expansion upon phase change. The ring becomes more asymmetric with respect to the mid-plane when gravity, in terms of the Bond number, becomes more dominant. However, volume change does not affect the asymmetry of the ring. Instead, volume change significantly influences the size of the ring. The influences of the growth angle, the supercooling degree and the bridge aspect ratio on the evolution of the solid phase, the solidified bridge shape and solidification time are also revealed.