Experimental and DEM based characterization of flowability of non-spherical and spherical bauxite particles

The flowability of granular bauxite materials critically affects the efficiency of industrial systems such as moving bed heat exchangers (MBHEs) in concentrated solar power (CSP) applications. This study investigates the influence of particle shape and size on flow properties using experimental methods and Discrete Element Method (DEM) simulations. The static angle of repose (AoR) tests revealed higher AoR and flow resistance in non-spherical particles. Furthermore, dynamic and shear tests provided deeper insights into the flow behavior, highlighting not only shape-related effects but also a distinct sensitivity to particle size. Specifically, smaller non-spherical particles exhibited reduced interlocking and frictional resistance compared to their larger counterparts, whereas spherical particles demonstrated flow characteristics that were largely independent of size. DEM simulations were validated against experimental AoR data and accurately reflected shape-dependent behavior. The flow characteristics of cylindrical particles, which represent non-spherical shapes, exhibited a mild sensitivity to rolling friction parameters, in contrast to spherical particles, whose flow was more significantly affected by these parameters. Overall, these research results highlight the critical role of shape and size in flow behavior and provide a validated DEM framework for simulating bauxite flow, offering valuable insights for optimizing particle handling and enhancing MBHE performance in CSP systems.