Chapter 5. Modelling of Powder Flow

Abstract

This chapter reviews the fundamentals and applications of the most common methodologies used for modelling powder flow. Continuum and discrete approaches, such as the finite element method and the discrete element method (DEM), are described briefly. Continuum methods function based on constitutive laws, including the conservation of mass, momentum and energy, as well as the relationship between the stress tensor and strain rate in a discretised computational domain. Particles and their interactions are not explicitly considered in this approach; nevertheless, this method is computationally affordable for modelling industrial processes. On the other hand, discrete models have the ability to directly incorporate the interactions of the particles into simulations and to model the movement of individual particles. Based on this, discrete models offer invaluable insight into particle behaviour in different powder flow regimes. However, modelling a large number of particles using DEM is still a challenge and sometimes a hindrance. The applications of numerical modelling in different processes, namely hopper discharge, filling and blending, are reviewed. These simulations are mainly influenced by process conditions, such as the speed of a process and wall pressures, as well as particles attributes, i.e. size distribution, shape, density, and surface conditions. While DEM-based models have made significant progress in considering the effects of these parameters, the continuum approaches are yet to develop more.