Simulation of mass flow rate of particles discharged from hopper by Particle Element Method

Flow behavior of particles discharged from an orifice of a hopper is simula ted three dimensionally by the Particle Element Method, PEM (Discrete Eleme nt Method, DEM), and the relation between the mass flow rate (W) and the or ifice diameter (D) is discussed in conjunction with the cyclic formation-co llapse phenomena of the arch formed over the orifice. The simulated relatio n is consistent with the empirical one, expressed as W proportional to D-n (n = 2.5-3.0). W is expressed as functions of three parameters, which are t he cross sectional area of the orifice (A), the flow velocity (v), and the volume fraction of flowing particles at the orifice (gamma). A is the param eter with most effection W, because it is proportional to D-2. In addition, v influences W at one-quater of A's contribution, while gamma's contributi on is only one-quater of A's one or less, depending on the frictional coeff icient of particle. The frictional coefficient of the particle is an import ant factor for controlling the mass flow rate of particles.