Discrete particle simulation of particle flow and separation on a vibrating screen : effect of aperture shape

This paper presents a numerical study on the effect of aperture shape on particle flow and separation in a vibrating screen process. A three-dimensional discrete element method (DEM) model is developed to simulate vibrating screens with rectangular apertures of different aspect ratios and orientations. Based on the model, the effect of aperture shape on the sieving process is studied through a series of controlled numerical experiments. The sieving performance is analysed in terms of overall percentage passings of different sized particles and the distribution of percentage passings along the screen deck. In addition, the sieving behaviour of individual particles is analysed based on the microdynamics information, particularly the particle-screen interactions. On this basis, the probability of a single attempt and the number of attempts for a particle to pass an aperture are modelled for different shaped apertures, which are linked to the macroscopic sieving performance. The results are useful for developing a fundamental understanding of the effect of aperture shape on screening, which will help design, control and optimise practical processes.