A computational model for finite element analysis of the freeze-drying process

A brief overview of the freeze-drying process is given, followed by presentation of the governing equations and the finite element formulation in two-dimensional axisymmetric space. The model calculates the time-wise variation of the partial pressure of water vapor, the temperature, and the concentration of sorbed water. An Arbitrary Lagrangian-Eulerian method is used to accurately model the sublimation front of the freeze-drying process. Both the primary and secondary drying stages of the process are modelled. Examples are presented that validate the model and demonstrate representative applications of such calculations.