Effect of mixing ratio on flow characteristics of binary particles in a fluidized bed

Understanding the flow characteristics of binary non-spherical particles in a gas-solid spouted bed is important to improve the process design of the equipment. In this paper, the effect of the volume fraction share of spherocylindrical particles versus spherical particles in a binary particle system on the particle fluidization mechanism inside a spouted bed is analyzed by CFD-DEM method. Particle forces, velocities, collisions, mixing, and concentration distribution characteristics were investigated through qualitative and quantitative perspectives, respectively. The results show that with the increase of the volume fraction of spherocylindrical particles in the binary particle system, the drag force of different types of particles increases and the average velocity decreases, which helps to improve the mixing rate of different types of particles, and the rotational velocity of spherocylindrical particles increases and the rotational velocity of spherocylindrical particles decreases, which accelerates the collision frequency of the particles tends to be in a stable state. Increasing the superficial gas velocity helps to increase particle drag force, mixing properties, and rotational velocity. However, the average velocity of the particles does not necessarily increase (e.g., Vol = 25 % and Vol = 50 %). In addition, the spherocylindrical particles contact force is significantly larger than the fluid-particle interaction force, and the values of the forces are, in descending order, particle contact force, pressure gradient force, drag force, virtual mass force, and lift force. Compared with the low bed layer, the particles in the high bed layer are more significantly affected by the gas flow perturbation and the flow is more active.