The processes of granular material handling in the hoppers are of a great importance in pharmaceutical, chemical, food and other industries. Theoretical treatments of such problems are usually based on simplified continuum models, which are useful to predict the stress field within the hopper, especially, on the walls at the end of filling process. The Continuum approach has some drawbacks for discharge state modeling when description of transient flow is required. Consequently, discrete element method (DEM) based on the application Newton’s and contact mechanics laws predicting dynamical parameters, such as position, velocity, etc., of individual particles, have been adopted in numerical analysis of granular flow in hoppers.
Filling and discharge flow in pyramidal hoppers of different shape is considered by the discrete element method. Non-cohesive frictional visco-elastic spherical particles are applied in modelling. The boundary conditions are described by using locally oriented planes of a finite size enabling to handle different shapes of hoppers. Evolution of the system kinetic energy, discharge mass fraction as well as distribution of particle velocities and material porosity fields is considered. Geometry of the hopper, particle contact forces and the velocity fields during discharge are presented in Fig. 1.
Hopper geometry, particle flow (a) and velocity fields (b) during discharge at
The DEM concept is implemented into original software code DEMMAT [
], where the
order Gear’s predictor-corrector
scheme is used for numerical integration of equations of motion. Particular postprocessors for evaluation of various field variables are also developed.