THE SIMILAR PARTICLE ASSEMBLY (SPA) MODEL, AN APPROACH TO LARGE-SCALE DISCRETE ELEMENT (DEM) SIMULATION

摘要

The "Similar Particle Assembly (SPA) Model" is proposed for large-scale discrete element method (DEM) simulation of particulate systems. The model includes the scaling law for the motion of particles in an assembly, which is derived from the equations of motion of particles. In the SPA model the motion of multiple particles whose diameter, density and chemical composition are the same is represented by one particle, which is called a representative particle. A representative particle occupies the same volume as the sum of the volume of represented particles and has the same density and chemical composition. The local assembly of different particles in the original bed is supposed to be maintained in the bed of representative particles. With the SPA model the flow of the bed of representative particles of a certain magnification can be made similar to that of the original particles with a much less computation load. The most significant aspect of the SPA model is that it can be applied to beds of cohesive particles as well as particles of non-uniform sizes. The model was validated by numerical simulation of a two-dimensional bed of non-cohesive particles of equal properties, a bed of particles of two different densities and cohesive particles up to the magnification of 6.