Predictions of Dead Zone Boundaries of Bulk Solids in Two-Dimensional Gravity Flows

This paper deals with dead zones in two cases of flow patterns of bulk solids. One is seen in hoppers or silos where dead zones are formed near the side wall since the exit is provided in the center of the bottom, leading to the converging flow of particles. The other is that represented by the deadman formed in the center of an ironmaking blast furnace as a result of coke particles descending towards the surrounding side wall in a diverging manner. Slip line analysis is used for predicting the dead zone boundaries in the two cases. The state of stress field, active or passive, is determined by the flow pattern of bulk solids. The internal and the wall frictions are also examined both theoretically and experimentally, and thus comparison becomes possible between theory and experiment. The results are satisfactory.