COREX熔化气化炉风口回旋区CFD+DEM数值模拟

Numerical Simulation of COREX Raceway by Coupling Between CFD and DEM

COREX熔化气化炉风口回旋区是炉况顺行的基础,在冶炼过程中起着十分重要的作用,为了描述其形状和大小,建立了CFD+DEM(Computational Fluid Dynamics and Discrete Element Method)耦合模型,对回旋区形成过程及大小进行了颗粒尺度的分析.得到床层高度为0.4m,气体速度11.74m/s的条件下回旋区颗粒空隙度分布,当吹气时间为0.13s时,气体入口附近有颗粒被吹开,随着时间的推进,气体动能吹开的颗粒增多,0.19～0.21s时,形成的回旋区开始稳定.对入口处不同气体速度条件下回旋区及其附近颗粒速度进行了计算模拟.模拟结果显示,风口附近颗粒在做回旋运动,并且随着入口气体速度的增大,吹开的颗粒增多,回旋区空腔增大,当入口气体速度为11.74m/s和16.83m/s时形成的回旋区较稳定,当入口气体速度大于21.90m/s时形成的回旋区不太稳定.

The raceway plays a very important role in the blast furnace and COREX ironmaking processes and is also the basis of smooth operation of the furnaces.In order to describe its shape and size,a combined discrete element method(DEM) and computational fluid dynamics(CFD) model was developed.The particle porosity of raceway with bed height of 0.4 m and gas blowing velocity of 11.74 m/s was obtained.When blowing time was 0.13 s,some of particles which are nearby the gas inlet were blown away.The number of particles increased with the increased time.When blowing time was 0.19~0.21 s,the raceway began to stabilize.The particle velocity inside and around raceway at different blast velocities was simulated.The results showed that the particles which are nearby the tuyere make circular cyclotron motion,and the raceway increases with the increased gas blowing velocity.When the gas velocities are 11.74 m/s and 16.83 m/s,the raceway is more stable.When the velocity is greater than 21.90 m/s,the raceway becomes unstable.