A Review of Distribution and Segregation Mechanisms of Dockage and Foreign Materials in On-Farm Grain Silos for Central Spout Loading

Dockage and foreign material (DFM) distribution in grain silos is an important factor in managing stored grain. The DFM distribution in grain silos is dictated by the segregation mechanisms of DFM during grain loading. Loading grain into silos from a central spout is a special case of heap flows of granular materials. However, our understanding of heap flows is still evolving, and no models are currently available to predict the dockage and foreign material distribution in grain silos. Based on an extensive literature review, this paper identified the dominant mechanisms of DFM segregations during central spout filling in grain silos and main factors influencing DFM distribution. The DFM distribution patterns were characterized. The experimental methods for analyzing DFM segregations and distribution were also reviewed. The gaps of our knowledge on segregation mechanisms and factors influencing segregation were summarised and future research directions and challenges were discussed.