Numerical and experimental study of radial segregation of bi-disperse particles in a quasi-two-dimensional horizontal rotating drum

摘要

Radial segregation easily occurs in a horizontal rotating drum partially filled with particles of different properties under various operational conditions.DEM(discrete element method)simulations and experiments were combined together to investigate the segregation of bi-disperse particles of the same density but unequal sizes in a quasi-two-dimensional horizontal rotating drum.A linear spring-dashpot model was adopted in simulations.An easy and effective image analysis was conducted for the segregation/mixing of particles of different sizes.By comparing the repose angles,degrees of segregation,and particular phenomenon("sun pattern"and reverse segregation)in simulations under different operating conditions with those in experiments,the discrete-element model is verified.The effects of rotational speed and volume ratio on radial segregation are also considered systematically.From an analysis of the results of experiments and simulations,the degree of segregation generally decreases with increasing rotational speed,whereas the volume ratio shows different influences on segregation in different flow regimes.Moreover,the mechanism underlying the reverse segregation in the cataracting regime has been clarified as well.