Numerical Simulation of Blast Furnace Raceway Depth and Height, and Effect of Wall Cohesive Matter on Gas and Coke Particle Flows
Numerical Simulation of Blast Furnace Raceway Depth and Height, and Effect of Wall Cohesive Matter on Gas and Coke Particle Flows
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DOI：
10.2355/isijinternational.45.1416
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发表时间：
2005
影响因子：
1.8
通讯作者：
T. Umekage;S. Yuu;Masatomo Kadowaki
中科院分区：
文献类型：
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作者：
T. Umekage;S. Yuu;Masatomo Kadowaki
本文给出了与工业高炉尺寸相同的实际高炉回旋区颗粒和气体流动的计算结果。采用离散元法计算了焦炭颗粒间的多体相互作用，采用有限差分法对含气固相互作用项的Navier-Stokes方程进行了数值分析，计算结果显示了实际高炉内典型的回旋区形态以及气固速度和空隙率的典型分布。计算结果给出了滚道的尺寸和形状。这些随时间变化，表现为不稳定和不稳定的运动。滚道深度和高度都呈周期性变化，大致有两个不同的周期。滚道深度和高度的计算平均值与Matsui等人的测量数据相当吻合（ISIJ Int.，45（2005））因此，我们的计算值呈现了对实际高炉中的回旋区特性的粗略但适当的估计。喷嘴出口计算压力的不稳定变化也表明了两个不同的周期，其值与滚道的值一致。短周期反映了回旋区的一般波动，长周期反映了回旋区流量的大幅度变化。结果表明，回旋区在短时间内发生长大和收缩，在长时间内形状和尺寸发生较大变化，计算结果给出了高炉内一个异常现象实例，即由于气流穿透回旋区外侧形成的粉粒壁而形成的异常高风速宽接触区，计算了实际高炉炉内气体和颗粒的瞬时速度矢量，以及炉壁含粘结剂的瞬时含气率等值线。粘性物质显著改变了气体和颗粒的流动，特别是靠近炉壁的流动。
We have presented the calculated results of the particle and the gas flows in the raceway region in an actual blast furnace of which dimension is the same as that of the commercial blast furnace. We used Distinct Element Method for the computation of the multi-body interaction among coke particles and Finite Difference Method for the numerical analysis of Navier-Stokes equations with the interaction terms between gas and particles for the gas flows.The calculated results show a typical raceway pattern and typical distributions of gas and particle velocities and void fraction in an actual blast furnace. The results present the size and the shape of raceway. These change as the time and show the unstable and unsteady motion. Both of the depth and the height of raceway periodically change and have roughly two different periods. The calculated mean values of the depth and the height of raceway are fairly in good agreement with the measured data by Matsui et al. (ISIJ Int., 45 (2005)) Thus our calculated values present the rough but the proper estimation of raceway characteristics in an actual blast furnace. The unsteady change of the calculated pressure at the nozzle outlet also indicates two different periods of which values agree with those of the raceway. The short period would indicate the usual fluctuation of the raceway and the long period would do the large scale change of the flow. These results show that the raceway grows and shrinks during the short period and greatly changes its shape and size during the long period.Calculated results present an unusual phenomenon example in the blast furnace, namely the unusual high air velocity wide region touched to the furnace wall is formed due to the air flow penetrated the powder particle wall formed around the outside of the raceway, the effect of the softening melting zones and the size reduction of coke particles in the furnace center region.We calculated the gas and particle instantaneous velocity vectors, and the instantaneous iso-contour of void fraction with the cohesive matter on the furnace wall in the actual blast furnace. The cohesive matter considerably changes the gas and the particle flows, particularly dose the flows near the furnace wall.