NUMERICAL SIMULATION OF AIR AND COKE PARTICLEMOTIONS IN BLAST FURNACE TO MINUMIZE CO_2 EMISSION

采用离散元法对焦炭颗粒间多体相互作用进行数值模拟，采用蒙特卡罗法直接模拟的硬球模型对粉末颗粒间两体相互作用进行数值模拟，采用有限差分法对含气粒相互作用项的Navier-Stokes方程进行数值分析，对气体流动进行数值模拟。在模拟中，我们考虑了软融黏结带和黏结物质的存在。计算结果显示了不同的流型、波动和周期。结果还显示了焦炭、粉末和气体的速度分布以及这些颗粒的堆积比分布。动态特性是波动的，是不稳定的。高度堆积的焦炭和粉末颗粒层是在风口下的下壁和下芯区形成的。高风速区出现在软化熔化黏结区与高填充炉下芯区之间的一层，由于软化熔化黏结区的存在和消失，在炉壁附近和滚道上产生了不稳定的高风速区。焦炭、粉粒和软化的熔合带会使炉内产生不稳定状态。粉末颗粒循环扩散，形成圆形多层粉末颗粒团簇，造成颗粒碰撞和团簇破碎。粉末颗粒有的向上流动，有的被颗粒和气流包裹在炉膛下芯区。计算结果表明，在高炉中出现了一种不寻常的现象，即由于熔化黏结区的软化、黏结物的存在以及炉心区域焦炭颗粒的缩小等因素的影响，形成了不寻常的高风速宽区。少

We have numerically simulated the particle and gas flows in a real blast furnace using Distinct Element Method for the computation of the multi body interaction among coke particles, Hard Sphere Model for two body interaction of powder particles based on Direct Simulation of Monte-Carlo Method and Finite Difference Method for the numerical analysis of Navier-Stokes equations with the interaction terms between gas and particles for the gas flows. In the simulations we have taken the existence of softening melting cohesive zones and cohesive matters into account. The calculation results indicate the various flow patterns, those fluctuations and its various periods. The results also indicate the velocity distributions of coke, powder and gas, and packing ratio distributions of these particles. The dynamical characteristics fluctuate and are unstable. The highly packed coke and powder particle layers are formed in the lower core and in the lower wall regions under the tuyere due to the air … More and these particle flows. The high air velocity region appears in the layer between the softening melting cohesive zones and the highly packed furnace lower core region, and the unstable high air velocity region is produced near the furnace wall and on the raceway by the existence and the disappearance of softening melting cohesive zones. The coke and powder particles and the softening melting cohesive zones would yield the unstable state in the furnace. The powder particles circularly spread and make the circularly multi-layered powder particle clusters caused by the particle collisions and the breakage of clusters. Some of the powder particles flow upward and others are packed in the furnace lower core region by the particle and the air flows. Our calculated results present an unusual phenomenon example in the blast furnace, that is, the unusual high air velocity wide region touched to the furnace wall is formed due to the effect of the softening melting cohesive zone, the cohesive matter and the size reduction of coke particles in the furnace center region. Less