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Passage/FreezeDrying is a computer program designed for the
simulation of freeze drying processes in vials and pans. Passage/FreezeDrying provides modeling of containers with axisymmetric
boundary conditions with both primary and secondary drying
simulation capabilities. The software also handles containers with
asymmetric boundary conditions, as in the case of vials placed in
corners or near the walls of freeze-drying ovens.
The user-friendly, interactive preprocessor accepts externally
generated meshes and support automatic entry of material properties,
process conditions, and display of geometry.
Passage/FreezeDrying also has user-friendly, interactive
post-processing modules which display the computed temperature,
vapor concentration, water pressure, and glass transition
distributions in the form of contour plots and x-y graphs.
Animation of sublimation front movements can also be obtained
easily.
Temperature and pressure distribution after 8 hrs. of primary
drying in a vial
Sorbed water concentration in primary drying
Sorbed water concentration in secondary drying
Some objectives of using CAE is to identify freeze drying
process conditions to:
- Maximize drying rate and increase production
- Prevent chemical & structural degradation
- Provide uniform drying throughout the material
- Predict drying time for primary and secondary stages to
desired levels of water concentration
Some results of the analysis:
- Time for primary and secondary drying of products
- Location for isolated islands of ice in pan drying
- Concentration contours
- Absorbed water concentration
- Interface position in time
- Sublimation frontal movement
- Temperature contours and history
- Water pressure contours
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