UNIDIRECTIONAL FREEZING OF BINARY AQUEOUS-SOLUTIONS - AN ANALYSIS OF TRANSIENT DIFFUSION OF HEAT AND MASS

A model is presented describing the transient freezing of a binary aqueous solution in a region of finite extent. The model consists of three partial differential equations that are coupled by common non-linear boundary conditions in analogy to similar 'moving boundary' problems. The essential assumptions are as follows: constant cooling rates imposed at the boundaries of the system, transport of heat and mass by diffusion only, macroscopically planar phase boundary, total rejection of solute at the phase boundary and local thermodynamic equilibrium at the phase boundary.