Multiple drops solidifying on a surface with a temperature gradient

Abstract

In many applications, liquid drops perform their solidification on a surface of non-constant cooling temperatures. Such a surface results in various behaviors of drops during the solidification process. Revealing this solidification is the central point of the present study through numerical simulations. Three liquid drops simultaneously start to solidify on a sub-melting-point temperature surface. The surface is coldest on the right side and its temperature linearly increases with respect to the position from the right to the left, resulting in a surface temperature gradient. Thereby, the phase-change interface becomes inclined in all drops with its slope increasing with the surface temperature gradient. The rightmost drop finishes its solidification first while the leftmost drop completes last. With volume expansion, an apex located at the drop top always occurs for all solidified drops. However, unlike drops on a constant temperature surface, the apex of the drops with the surface temperature gradient has a tendency to shift more to the left, resulting in an increase in the apex shift with the surface temperature gradient.