In the Euler-Lagrange coordinate system

mixing characteristics of particles in a single jet fluidized bed were studied with discrete element method. A mixing index was introduced to quantitatively analyze axial and radial mixing quality in the bed

as well as to investigate influnce of superficial gas velocity and spring constant on mixing charcteristics. The simulation provided sequence diagrams of axial and radial mixing

distributions of gas and particle velocities

and mixing index distributions of particles across the bed at various parameter settings. The results showed that particle mixing process in the bed was determined by capacity of particle circulation and diffusion. Axial mixing rate was mainly controlled by internal circulation speed of particles

whereas radial mixing rate was mainly controlled by particle diffusion capacity. With the increase of superficial gas velocity

the internal circulation speed of particles was enhanced and thus axial mixing process was accelerated but radial mixing was weakly influenced. When spring constant was increased

both mixing speed and quality of particles were decreased as well as radial mixing process was less affected than that axial mixing by spring constant.