CFD-DEM -DDM Model for Spray Coating Process in a Wurster Coater

Area of Science:

• Chemical Engineering
• Pharmaceutical Sciences
• Computational Modeling

Background:

• Wurster coaters are crucial for pharmaceutical solid dosage form coating.
• Understanding particle behavior within the coater is essential for process optimization.
• Particle shape effects on coating uniformity require further investigation.

Purpose of the Study:

• To develop and validate a multiscale computational model for simulating lab-scale Wurster coating.
• To investigate the influence of particle shape (spherical vs. cylindrical) on coating processes.
• To identify optimal spray zones within the coater for improved coating efficiency and uniformity.

Main Methods:

• Coupling of Computational Fluid Dynamics (CFD), Discrete Element Model (DEM), and Discrete Droplet Model (DDM).
• Simulation of two case studies: 45,000 spherical particles and a mixture of 22,500 spherical and 22,500 cylindrical particles.
• Analysis of particle residence time distributions (RTD) and spray droplet-particle contact positions.

Main Results:

• Residence time distribution (RTD) within the accurate spray zone correlates with final particle size distribution.
• Particle shape significantly influences coating mass distribution and uniformity.
• The study identified optimal spray zones based on droplet-particle interactions and RTD.

Conclusions:

• Multiscale modeling provides valuable insights into Wurster coater dynamics.
• Particle shape is a critical parameter affecting coating outcomes.
• RTD analysis in conjunction with contact analysis aids in optimizing coating processes and product quality.