Charging behavior in a bell-less blast furnace based on 3D discrete element method

A bell-less blast furnace charging model was established by using 3D discrete element method. The flow behavior of particles in the hopper and rotating chute, the falling trajectory and heaping process of particles discharged from the rotating chute were modeled and analyzed by using this model. Consequently, the charging process was reproduced visually. It is found that size segregation is always prevalent throughout the flow process of particles. The discharging flow from the hopper is funnel flow, and small particles tend to be discharged in the later stage due to size segregation. It is proved that the influence of chute inclination angle on the particle behavior and heaping process is very significance. The granular flow in the chute deviates upward to one side and tumbles attributing to rotation. Small particles close to the chute wall surface move to the inside of the stream, while large ones staying at the upper part of the chute flow move to the outside. The falling trajectory of particles is affected by particle size segregation, deflection and tumbling, and velocity distribution. During the process of burden falling and heaping, large particles are apt to segregate to the center and periphery of the furnace throat, while small particles locate under the pile top and they are partial to the center due to locating inside the stream and permeation. The applicability of the model has been verified by the measurement results of burden trajectories based on the laser grid in-furnace measure technology.