COREX竖炉物料运动流型及瞬态特性的离散元模拟

基于离散单元数值计算方法,建立COREX竖炉内物料颗粒尺度运动行为的数学模型,研究炉内物料运动流型及其瞬态特性,特别是颗粒的瞬态速度和瞬态应力分布.模拟结果表明:COREX竖炉内存在三种类型的流动区域:活塞流区、准停滞区以及沟流区.炉内颗粒的瞬态速度分布表明炉内存在两种类型的速度波:装料过程引发的向下传播的速度波和底部排料引发的向上传播的速度波.COREX竖炉内颗粒法向应力随时间的变化较小,竖炉底部导流锥顶部存在较强的应力区,而无导流锥竖炉底部中心存在较强应力区,沟流区的应力较弱.

Discrete Element Simulation of Solid Flow Pattern and Transient Features of Burden Descending in COREX Shaft Furnace

A mathematical model based on discrete element method (DEM) was developed to investigate the behaviors of solid particulate motion in a COREX shaft furnace model from particle-scale view. The solid flow pattern and transient features of burden were simultaneously analyzed， especially the transient behavior of velocity and stress distribution were calculated. The results showed that the solid flow in COREX shaft furnace can be divided into three different flow regions: plug flow zone， quasi-stagnant zone and converging flow zone. The transient behavior of velocity distribution indicates that there are two types of velocity waves in the furnace. One is a downward wave caused by charging and the other is upward from bottom caused by discharging. The normal stress has a minor change with time. A high stress field exists on the top of the guiding cone， while for the furnace without guiding cone， the particles in the lower central zone present strong normal stress. On the contrary， the particles exhibit weak normal stresses in the converging flow zone.