Arch formation mechanism and discharge process of cohesive fine powder in a vibrated silo

The arch formation mechanism and discharge process of a very cohesive fine powder (calcium carbonate) in a vibrated silo was investigated by experiments and discrete element method (DEM) simulations. An experimental setup is built to study the flow behaviors with the proposed image-based flow rate measurement method. A cohesive DEM model is used to investigate the dynamic behaviors of the powder bed. Results indicate that the arch formation depends on the vibration acceleration amplitude and is slightly affected by the frequency. The powder discharge flow rate increases with vibration acceleration amplitude and decreases with frequency. When the acceleration amplitude exceeds 15 g, the flow rate tends to stabilize. When the acceleration amplitude exceeds 1 g, there is separation and collision between the powder bed and the silo bottom. This collision leads to a significant increase in the contact force.