Discrete element simulation of powder flow in revolution powder analyser: Effects of shape factor, friction and adhesion

Abstract

Through discrete element method (DEM) simulations in Revolution Powder Analyser (RPA), we found a strong correlation between the static powder bed packing density and the avalanche flow. A wider powder size distribution and a higher fraction of non-spherical powders caused larger misfits in the static packing of powders, and thereby enhanced the powder mobility during revolution, leading to an earlier avalanche. It performs a gradual avalanche under low friction, and an abrupt avalanche under high friction. The rolling motion of non-spherical powders was found to cause an instantaneous disturbance to the flow of neighbouring powders. It was also found that other factors, such as the filling degree, drum rotation speed and inter-powder adhesion, can also influence the measurement results and hence they must be controlled or standardized in order to achieve reliable and consistent measurements. Furthermore, based on the experimental measurements of avalanche angle and packing fraction, we extracted the intrinsic powder friction coefficient and adhesion energy. • DEM powder flow models with realistic powder size and shape distributions. • Performed DEM simulations to study powder flow profiles and avalanche phenomena. • Examined and identified the effects of system factors for reliable RPA measurements. • Extracted the rolling COF and adhesion energy by including powder non-sphericity.