Silo Discharge: Measurement and Simulation of Dynamic Behavior in Bulk Solids

Abstract

This paper deals with the experimental investigation and the numerical simulation of silo discharge processes, including dynamic interactions between the silo filling and the elastic silo walls. The discharge process is described by a system of nonlinear differential equations. Via the Finite Element Method (FEM) based on an EULERian reference frame, the deformation rate, the velocity field, the porosity, and the stress distribution can be calculated without the need of re-meshing the FE-grid. To compare simulation results with measured data, the numerical simulation examples are chosen to be similar to an experimental test-silo of the Institute of Mechanical Process Engineering at the Technical University of Braunschweig. Optical measurement techniques are applied to investigate the flow profile, and load cells on the silo walls register the stress evolution, e.g., a stress peak (switch) moving from the outlet to the transition from hopper to shaft.

How does internal angle of hoppers affect granular flow? Experimental studies using digital particle image velocimetry

“…(Figs.8-9). The dilation of particles in ploughs could significantly affect the granular bulk density and the wall stresses [13]. However, in the case of 90 o hopper, in addition to the above mentioned two phases (Figs.8-9), the third phase of the flow occurred mostly radially inwards indicating an avalanche trend (Fig.11).…”

“…The way in which granular discharge occurs from storage outlets could lead to dramatic changes in the variation of normal and shear stress along their wall boundaries. This could subsequently affect the bulk density of granular assemblies inside their collection chambers [13]. The tendency of granular materials to form arches inside different hopper geometries during flow and the related properties such as granular jamming have been investigated extensively using both experimental and numerical methods [4,6,[14][15][16].…”

Experimental observations on the different mechanisms for solid ejection in gas-fluidized beds

“…Different works can be found in the literature using PIV in granular flows [32], silo discharge [33][34][35] and fluidized beds [26,12]. The same PIV software used by Müller et al [26](MATPIV 1.6.1 [36]) and the same iterative process and filters of this work were followed.…”

Finite element investigation of the flow and stress patterns in conical hopper during discharge

“…FEM associated with elastoplastic constitutive theories can give satisfactory predictions of the internal stress and wall pressure in hoppers (Ooi and Rotter, 1990;Rotter et al, 1998;Goodey et al, 2003Goodey et al, , 2006Goodey and Brown, 2004;Vidal et al, 2006Vidal et al, , 2008Ding et al, 2013). However, its application to reproduce the flow conditions of granular material is usually not easy Sanad et al, 2001;Tejchman and Klisiński, 2001) and requires some particular schemes or treatments such as the re-meshing and re-zoning scheme (Sanad et al, 2001), adaptive meshing technique (Yang et al, 2011), viscoplastic granular fluid models (Haussler and Eibl, 1984;Karlsson et al, 1998;Elaskar et al, 2000;Böhrnsen et al, 2004), smoothed particle hydrodynamics (SPH) method (Sugino and Yuu, 2002), and material point method (MPM) (Wieckowski et al, 1999).…”