Abstract
The storage and efficient withdrawal of material from silos and hoppers is basic to numerous industrial processes. Practising engineers classify two fundamental flows, namely mass-flow and funnel-flow. The former describes the situation when the bulk solid is in motion at every point in the silo or hopper, whenever material is drawn from the outlet. The latter describes the situation when a stable channel forms, called a rat-hole, and the flow is such that only material above the rat-hole is in motion. Funnel-flow occurs whenever the outlet walls are too rough and not sufficiently steeply sloped. Funnel-flow is generally erratic and can give rise either to segregation problems or may lead to complete blockage of the outlet. Here two relevant analytical solutions of the equations for the non-dilatant double-shearing model of granular flow are presented for both plane and axially symmetric funnel-flow. These solutions give rise to flow patterns which are similar to those observed in funnel-flow in the discharge of rectangular and circular cylindrical silos and hoppers.
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Spencer, A., Hill, J.M. Non-dilatant double-shearing theory applied to granular funnel-flow in hoppers. Journal of Engineering Mathematics 41, 55–73 (2001). https://doi.org/10.1023/A:1011820810780
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DOI: https://doi.org/10.1023/A:1011820810780