Separation of particulate solids by screening – a discrete particle simulation
Discrete element modeling has been widely used for the simulation of microscopic interactions between particles, fluids and boundaries. In most of these applications to date, the boundary is usually a stationary solid surface. However, many engineering processes, such as fluid/solids separation, encounter an absorptive boundary that acts as multiple go/no-go gauges to screen particles according to sizes. This paper presents a numerical model for the study of particle screening process using the Discrete Element Method. Special attention has been paid to the implementation of a meshed screen boundary with vibration to allow particles to pass through or to rebound when approaching the screen surface. Simulations have been conducted to examine the two inter-linked physical mechanisms involved in particle screening operations: particle segregation in material layers and particle passage through apertures. Modeled results have shown the importance of coupling these two mechanisms to achieving optimal operation.