Unsteadiness and resolution effects in experimentally verified simulations of a spray drying process

In this work, time-resolved three-dimensional numerical simulations supported by laboratory experi-ments aim to provide complementary information of the spray drying process, revealing pivotal details about the flow and particles dynamics. A drying model was implemented in the OpenFOAM open-source code and large-eddy simulations (LES) of the flow were performed on a BUCHI Mini-sp ray dryer using real working conditions and input parameters. This work involved simulating a realistic number of particles (10,000 particles/s), higher than those commonly used. The simulation allowed to describe the average strong recirculation in the drying chamber, highlighting the wide spread of the residence time of each particle and how it affected its distribution. The percentage of product loss due to wall con-tamination is in good agreement with those in the experiment, showing that the simulations are reliable. This study illustrated the importance of unsteady and well-resolved simulations to gain insight into how flow characteristics affect particle trajectories and the product quality, giving information complemen-tary to experimental measurements. Our observations also showed the importance of an appropriate res-olution to describe flow features, those identification is crucial to design new devices with greater efficiency.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this work, time-resolved three-dimensional numerical simulations and laboratory experiments were performed to investigate the spray drying process. The simulations provided insights into the flow and particle dynamics, while the experiments validated the reliability of the simulations. The study highlighted the importance of unsteady and well-resolved simulations in understanding the impact of flow characteristics on particle trajectories and product quality.