Flow patterns of cohesive feed in a model bin with flow-corrective inserts

摘要

Tests were performed to study the flow behaviour of cohesive feed in a model bin with bin inserts. The 2.4-m high rectangular fain, with cross section of 0.4 m x 1.0 rn and a shallow hopper of 60 deg. wax constructed from plywood and plexiglass so that the transparent front wall allowed the material movement to be observed and recorded by a video camera. Captured video images were then digitized to determine the flow patterns and velocity profiles. Compared with flow from the bin with no inserts, discharge of cohesive feed was more consistent when an insert was installed. Specifically, no permanent arching occurred: little variation was observed between test replicates; and the discharge rate increased 53% when an insert was installed at the bin-hopper transition (BHT). The insert was more effective in reducing arching when installed near EHT than other locations. When the insert was allowed to swing in the bin (rotating insert), it oscillated (+-2 deg) during discharge. This oscillatingmotion prevented stable arches from forming. The bin insert changed the material flow from the funnel to mass flow mode. However, feed did flow uniformly inside the bin. The insert divided feed into two flow channels, with a fast channel on the left side of the binand a slow one on the right.