The phenomena of solidification and melting are associated with many practical applications.
They occur in a diverse range of industrial processes, such as metal processing, solidification
of castings, environmental engineering and thermal energy storage system in a space station.
In these processes, matter is subject to a phase change. Consequently, a boundary separating
two different phases develops and moves in the matter during the process. Transport
properties vary considerably between phases, which result in totally different rates of energy,
mass and momentum transport from one phase to another. In these problems, the position
of the moving boundary cannot be identified in advance, but has to be determined as an
important constituent of the solution. The term ‘moving boundary problems’ is associated
with time-dependent boundary problems, where the position of the moving boundary must
be determined as a function of time and space. Moving boundary problems, also referred to
as Stefan problems, were studied as early as 1831 by Lame and Clapeyron [1]. However, the
sequence of articles [2, 3] written by Stefan has given his name to this family of problems,
which resulted from his study of the melting of the polar ice cap around 1890.