Using a coupled CFD - DPM approach to predict particle settling in a horizontal air stream
Preventing health and safety hazards such as dust explosions and respiratory exposure in the work force when handling and storing fine powders is a major challenge faced by plant operators . Computational Fluid Dynamics (CFD) coupled with Discrete Phase Model (DPM) can be used as a tool to address this challenge by advancing the understanding of how particles deposit in a particular process. Particle settling, in air streams, is primarily dependent on the drag forces exerted on the individual particles through interactions with the suspension medium . By improving the understanding of this interaction through repeatable experiments and simulations; more complex CFD - DPM simulations are possible, thus providing a significant step in reducing the risks associated with handling fine powders. To study the transport and settling of particles in air streams, an experiment was established where glass beads, alumina and iron ore dust were injected into a horizontal flow channel. The material was fed into the top of the test rig where it was then transported in a laminar air stream. Through this method particle settling, according to the particle size, can be observed by sampling different trays along the bottom of the test rig. Once the deposition of particles is analysed (using a particle size analyser) each diameter range can be tracked to determine the distance travelled. After evaluating these experiments a CFD coupled with DPM simulation was employed to predict particle deposition in the horizontal chamber. The results show a good agreement between experiments and CFD - DPM results.