串罐式无钟高炉炉顶炉料运动的离散元分析

建立了串罐式无钟炉顶装料系统全模型，应用离散单元法对炉料从皮带到炉喉运动的全过程进行数值计算，考察了皮带上上下料罐内的粒度偏析，对比了料罐内是否安装石盒对料罐内炉料分布、料罐装料和卸料时炉料运动及布料时料流粒度变化的影响. 结果表明，皮带上小颗粒向料层下部渗透，皮带末端料层下部平均粒度比上部小. 炉料沿上料罐周向、径向和纵向存在粒度偏析；沿下料罐径向和纵向存在粒度偏析，周向上分布较均匀，相对粒度变化的标准差为0.03. 料罐内安装石盒对周向和纵向粒度分布影响较小，石盒附近小颗粒渗透影响径向粒度分布，料面基本水平，料罐卸料呈活塞流；无石盒时料面形成堆尖，料罐卸料呈漏斗流. 布料时料流粒度变化受料罐内料流运动和炉料分布影响，料罐内不安装石盒时料流粒度变化的标准差为7.15，安装石盒时为10.42，料流粒度变化更明显.

Analysis of Particles Movement in the Serial-hopper Bell-less Top of Blast Furnace with Discrete Element Method

A full model of serial-hopper bell-less type charging system of blast furnace was developed, and the movement of burden from conveyor to throat was calculated by discrete element method. Particle size segregation on the conveyor and in the upper and lower hoppers was studied, and the effects of installed stone box on burden distribution in the hopper, particle movement during charging and discharging and the size variation of discharged particles were analyzed. The results show that the small particles percolate into the lower material layer on the conveyor, which results in the average size of lower particles being smaller than that of the upper. Particle segregation exists in the vertical, circumferential and radial directions of upper hopper, and in the vertical and radial directions of lower hopper. However burden distribution in the circumferential direction of lower hopper is uniform, and the standard deviation of relative particle size is about 0.03. Installing stone box has little effect on burden distribution in the circumferential and vertical directions of hopper, however, the effect of stone box on burden distribution in the radial direction of hopper is large, since the small particles percolate near the stone box. The material surface is level and particles move in plug flow in the lower hopper with stone box, but burden surface forms heap tip and particles move in funnel flow without stone box. Change in mean size of discharged particles is affected by particle movement and burden distribution in the lower hopper. When stone box is not installed in hoppers, standard deviation of the size variation in discharging process is 7.15, and that is 10.42 with stone box and the change of discharged particle size is more obvious