Numerical Study of the Orientation of Cylindrical Particles in a Circulating Fluidized Bed

Orientation is pivotal in circulating fluidized beds using cylinder-shaped particles. This study developed a three-dimensional multiway coupling model for predicting the orientation of cylindrical particles in circulating fluidized beds. The coupling algorithm between motorial cylindrical particles and the turbulence was established by incorporating the correlation between Lagrangian time scales and the k-epsilon model. Collisions among cylindrical particles were solved by combining rigid body impact dynamics with the hard sphere model. The results showed that the majority of cylindrical particles are prone to align with the streamline, which is in good agreement with the experimental observation. Cylindrical particles become more oriented along rising height position in the riser, increasing the slenderness ratio and decreasing the distance to the wall. Under turbulence conditions, the effect of Reynolds number on the orientation of cylindrical particles was found to be marginal.