(87h) Development of a Continuum Model for Predicting Particle Segregation in Industrial Particulate Flows

Fan, Y., The Dow Chemical Company
As particulate solids flow they can segregate due to differences in particle size, density or other particle properties. Particle segregation has wide implication in various industrial processes such as hopper filling and discharge, mixing in rotating tumblers and chute transfer. The degree of particle segregation depends on flow conditions and differences between particles. We have recently developed a continuum model validated by experiments to quantitatively predict segregation. The model is based on an advection-diffusion equation for individual particle species with a semi-empirical percolation-induced segregation term. This continuum model incorporates three competing physical mechanisms for segregation – advection, percolation, and diffusion. The segregation term that we developed isolates the flow condition effect from the particle property effect on segregation, so that this segregation model can be applied directly to different flow geometries. We have applied this continuum model to several flow geometries including heap flows during hopper filling, hopper discharge, chute flows, and tumbler flows. We also extended this model to more practical conditions by considering particle polydispersity and three-dimensional flows. We continue to explore how the continuum model can be adapted to more complicated flow geometries and particle systems pertinent to industrial particle handling and processing systems.