高炉风口回旋区焦炭燃烧特性的颗粒尺度模拟

Particle-scale modelling of coke combustion characteristics in a blast furnace raceway

为从微观颗粒尺度解析高炉风口回旋区动态演变及内部热化学行为,采用计算流体动力学-离散单元法(CFD-DEM)耦合方法对回旋区焦炭燃烧过程进行了数值模拟研究。首先验证了CFD-DEM模型的可用性与准确性;然后探究了回旋区形成及演变过程、焦炭颗粒燃烧行为及粒径分布和气相的温度及组分分布;最后考察了不同鼓风速率对回旋区大小、风口轴向气体温度与组分分布的影响。模拟结果表明,回旋区的宽度和高度随着鼓风速率的增大而增加;鼓风速率的上升使气体高温区和化学反应区分布发生改变,即最高温度点和焦炭反应区均向焦炭床中心移动。

The multiscale method coupling computational fluid dynamics(CFD) with discrete element method(DEM) was employed to investigate the raceway dynamic evolution and inner thermo-chemical behaviors at particle level. The applicability and accuracy of CFD-DEM model were verified firstly. Then, the formation and evolution of raceway, the combustion behaviors and coke particles consumption, and the temperature and species distribution of gas phase were examined. Finally, the effects of blast rates on the raceway size, the axial gas temperature and species distributions of the tuyere were studied. The predicted results show that the raceway width and height enlarge with the increase of blast rate while the high temperature and coke reaction zones move towards the center of packed coke bed.