Effect of wall rougheners on cross-sectional flow characteristics for non-spherical particles in a horizontal rotating cylinder
Guang Lu;James R.Third;Christoph R.Müller;ETH Zürich, Department of Mechanical and Process Engineering, Institute of Energy Technology, Laboratory of Energy Science and Engineering,8092 Zürich, Switzerland;
Discrete-element-method(DEM) simulations have been performed to investigate the cross-sectional flow of non-spherical particles in horizontal rotating cylinders with and without wall rougheners. The nonspherical particles were modeled using the three-dimensional super-quadric equation. The influence of wall rougheners on flow behavior of grains was studied for increasing particle blockiness. Moreover,for approximately cubic particles(squareness parameters ), the rotational speed, gravitational acceleration and particle size were altered to investigate the effect of wall rougheners under a range of operating conditions. For spherical and near-spherical particles(approximately up to the squareness parameters ), wall rougheners are necessary to prevent slippage of the bed against the cylinder wall. For highly cubic particle geometries(squareness parameters larger than ), wall rougheners resulted in a counter-intuitive decrease in the angle of repose of the bed. In addition, wall rougheners employed in this study were demonstrated to have a higher impact on bed dynamics at higher rotational speeds and lower gravitational accelerations. Nevertheless, using wall rougheners had a comparatively small influence on particle-flow characteristics for a bed composed of finer grains.