A. Ramirez, C. González-Montellano, E.Gallego, F.Ayuga, J.M. Fuentes
Asabe
2010 ASABE Annual International Meeting
The discrete element method (DEM) is a numerical technique widely used to study the behavior of granular materials. It has proven to be reliable and effective in simulating many flow scenarios as well as the interaction between granular materials and the physical elements of the machinery or the physical system where they are contained.In this paper DEM is used to study the flow pattern developed during silo discharge as well as the wall pressure distributions at different stages of the filling and discharge processes. A small scale model silo with a hopper at its base has been simulated using DEM and considering spherical particles for the material stored. The material properties involved in the simulation where directly measured when possible, considering literature values or calibration values when not. The Hertz- Mindlin no-slip contact model with viscous damping and a frictional slider in the tangential direction has been considered in the simulation.The numerical model has been calibrated experimentally by comparing the numerical results with the observation of the filling and discharge of a real scale silo with transparent walls in laboratory conditions. This comparison focused on several variables, such as discharge rate, particle movements or bulk density achieved at the end of the filling stage. After that, numerical results are analyzed in detail. The flow pattern was analyzed qualitatively, by direct observations of the numerical results, and quantitatively, by means of the vertical velocity profile at different levels during the discharge process and the mass flow index at those levels. The wall pressure distributions were obtained by time-averaging the normal and tangential contact forces acting on each wall section.
Calibration, filling, silo discharge