(25c) Simulation of Drying of Droplets and Its Effect on Particle's Morphology in Spray-Drying

Spray-drying is a manufacturing process utilized by a wide range of industries such as food, agricultural, and pharmaceutical for converting a liquid feed containing insoluble solid particles into particulate form. By removing the moisture, it is intended to achieve a final product with desired chemical composition, morphology (hollow particles, solid cores, agglomerates, etc.), and particle size distribution. There are many variables that affect the drying process, and due to its complexity, traditional trial-and-error methods have been the primary technique in achieving the desired product.

The drying dynamics affect the internal flow patterns within a droplet in spray-drying. The flow patterns are dominated by surface tension and evaporative effects which ultimately disperse the suspended particles in the droplet and finally determine the final product morphology. In the presented work, the drying and internal transport of insoluble particles within a droplet were simulated using a volume of fluid method coupled with a Lagrangian solver for tracking particle movement. The simulations were performed within the open-source framework, OpenFOAM. The solver has been heavily modified to include interfacial mass transfer by employing a coupled Eulerian-Lagrangian framework capable of simulating drying of a droplet and the solid particles suspended inside. Modeling droplet’s internal flow created through evaporative effects, and tracking movement of solid particles, drying and the morphological evolution of the product is simulated and analyzed.