Abstract：The gas flow and solid field in cyclone tube was simulated.The movements of particles were described from 3 aspects which were the collision probability in different positions of dust discharge cone, back-mixing phenomenon and residence time distribution of particles. The results show that in the torus intersection with side seam, the collision probability reaches the highest, and the probability of wear or scaling is the biggest. As the particle diameter increases, the direct trapping proportion increases, and the back mixing proportion from the discharge dust port and ash bucket decreases. The proportion of back mixing from the discharge dust port is more than that from ash bucket. Within a certain flow rate range, the phenomenon of back mixing becomes serious with the less flow rate. With the particles diameter decreasing, the growth rate of particles residence time distribution in separation space and dust discharge cone becomes bigger, and the phenomenon of back mixing becomes serious.

Keywords：cyclone tube; particle motion; flow parameter; numerical simulation