Gravitational Flow Behavior of Granular Materials in Mass-Flow Hoppers

The behavior of gravity flow of cylindrical particles and silica sand was investigated using two-dimensional hoppers, of which hopper angles were adjustable. The velocity profiles and trajectories of cylindrical particles were observed, and the flow rates of the both materials were measured. These experimental values were compared with those estimated from our two-dimensional theoretical flow model considering the effect of particle properties such as the angle of wall friction. The following results were obtained : (1) The flow patterns of the both materials were mass flow and also radial flow, (2) The velocity profiles of cylindrical particles depended more clearly on the hopper angle than those expected from a previous theory, and it almost agreed with the calculated values, (3) The normalized discharge flow rate of cylindrical particles was well estimated by the theoretical model. However, the experimental values of silica sand were smaller than the theoretical estimation.