Simulation of a single spherical droplet drying considering shrinking and temperature profiles: first drying stage

Area of Science:

• Chemical Engineering
• Thermodynamics
• Drying Technology

Background:

• Convective drying is crucial for many industrial processes.
• Accurate modeling of droplet behavior during drying is essential for process optimization.
• Existing models may not fully capture simultaneous heating and evaporation dynamics.

Purpose of the Study:

• To develop and validate a model for simulating temperature, shrinking, and mass profiles of a spherical droplet during convective drying.
• To assess the model's applicability for the first drying stage.
• To evaluate the model's performance with different droplet components.

Main Methods:

• A mathematical model incorporating simultaneous droplet heating and water evaporation was developed.
• The model was validated using experimental data for skim milk and colloidal silica drying.
• Whitaker correlation at film temperature was considered for enhanced generic applicability.

Main Results:

• The model accurately simulates the initial heating time (approx. 7s) and evaporation at wet bulb temperature.
• Discrepancies between simulated and experimental values were within 9% for skim milk and 7% for colloidal silica.
• The model demonstrated good applicability for both dissolved and insoluble materials.

Conclusions:

• The proposed model effectively simulates the initial stage of convective droplet drying.
• The model shows broad applicability across different materials.
• Minor discrepancies were observed, and potential improvements were discussed.