Predicting discharge dynamics of wet cohesive particles from a rectangular hopper using the discrete element method (DEM)

Flowability of surface modified pharmaceutical granules: A comparative experimental and numerical study

“…Similar observations have previously been made in quasi-3D simulations of discharge of cohesive particles (Anand et al, 2009). …”

“…The discrepancy is most likely due to the fact that the parameters C and k were considered as standard and hence not determined for the various granules. Moreover, different procedures to correct for the hopper geometry exist in the literature (Anand et al, 2009).…”

“…(15) would be required for the cohesive ones (Nedderman, 1992;Anand et al, 2009). The range of Beverloo discharge rates is relatively narrow (3.4-3.9 g/s), and values in this range were obtained for all sliding friction coefficients, provided that the rolling friction was appropriately selected, indicating a good general agreement between Beverloo and simulated values.…”

“…From a more theoretical point of view, a number of studies have demonstrated the ability of the DEM to predict hopper discharge rate, both for spherical (Anand et al, 2008;Datta et al, 2008;Anand et al, 2009) and non-spherical particles (Cleary and Sawley, 2002;Tao et al, 2010). Often 2D (Datta et al, 2008) or quasi-3D (Anand et al, 2008;Anand et al, 2009) systems have been investigated (the latter employing periodic boundary conditions in one spatial direction), but examples of fully-3D simulations exist, especially for non-spherical particles (Cleary and Sawley, 2002;Tao et al, 2010). The studies demonstrated the dependence of discharge rate on hopper angle (Datta et al, 2008) and particle-particle interactions (Anand et al, 2008), including cohesion (Anand et al, 2009).…”

“…Often 2D (Datta et al, 2008) or quasi-3D (Anand et al, 2008;Anand et al, 2009) systems have been investigated (the latter employing periodic boundary conditions in one spatial direction), but examples of fully-3D simulations exist, especially for non-spherical particles (Cleary and Sawley, 2002;Tao et al, 2010). The studies demonstrated the dependence of discharge rate on hopper angle (Datta et al, 2008) and particle-particle interactions (Anand et al, 2008), including cohesion (Anand et al, 2009). When the DEM is used, friction is typically accounted for by using effective sliding (and rolling) friction coefficients, a practice that we will adhere to.…”