Experimentally validated CFD-tool for a freezing simulation in a small-scale freeze-dryer

This paper focused on the development of a 3-D coupled CFD model to predict and reduce the freezing time in small-scale freeze-dryers with an integrated freeze-drying chamber and ice trap. The proposed CFD model consists of three sub-models of different time and size scales to simultaneously consider thermal and flow processes inside the vacuum chamber, the food product, and the evaporator section. The model was validated against the experimental data collected for the commercially available unit. For this reason, the developed model is suitable for the forced airflow simulation in a closed chamber with stationary shelves and can easily be adapted as the CFD-design tool for other freeze-drying chambers. In consequence, the proposed model was used to improve the geometry of the freeze-dryer unit resulting in a 50% reduction in the freezing time compared to the reference design.