欢迎访问过程工程学报, 今天是

›› 2017, Vol. 17 ›› Issue (1): 21-28.DOI: 10.12034/j.issn.1009-606X.216273

• 流动与传递 • 上一篇    下一篇

高固含率搅拌槽内颗粒分布及悬浮特性的数值模拟

盛勇1,刘庭耀1,韩丽辉2,刘青1   

  1. 1. 北京科技大学钢铁冶金新技术国家重点实验室
    2. 北京科技大学冶金与生态工程学院
  • 收稿日期:2016-08-12 修回日期:2016-08-31 出版日期:2017-02-20 发布日期:2017-02-22
  • 通讯作者: 刘青

Numerical Simulation of Solid Particle Distribution and Suspension Characteristics in High Concentration Stirred Tank

SHENG Yong 1,2,LIU Yao-ting 1,2,HAN Li-hui 3,LIU Qing 1,2   

  1. 1. State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing
    2. State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing
    3. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing
  • Received:2016-08-12 Revised:2016-08-31 Online:2017-02-20 Published:2017-02-22
  • Contact: LIU Qing

摘要: 采用Euler-Euler双流体模型对固含率9.2%(?)的高固含率悬浮搅拌槽内固液悬浮特性进行了模拟,对比了两种修正的曳力系数模型的模拟效果,考察了固含率轴向和径向分布及悬浮均匀度的变化规律. 结果表明,搅拌速度低于600 r/min时,槽底会形成明显的中心密集沉积,转速从400 r/min增至1100 r/min,堆积高度由0.16减小至0,沉积区向槽底中心收缩直至消失. 在离心力的作用下,循环流内的固相颗粒向远涡方向运动,循环流涡心处固含率低,悬浮均匀性降低. 以无因次高度z/H=1/3为界,可将槽内两相流分为上、下循环区;颗粒分布受循环流交汇影响,固相在径向方向上随流场分散. 固液悬浮均匀度?随无因次轴向高度的增加,稳定在0.5~0.7,转速从400 r/min增至1100 r/min,上循环区的?值平均降低37.2%.

关键词: 固液悬浮, 搅拌槽, 固含率分布, 悬浮均匀度, 数值模拟

Abstract: Solid-liquid suspension characteristics of stirred tank with solid holdup 9.2% was simulated by Euler-Euler two fluid model. The simulation and prediction results of two kinds of modified drag coefficient models were compared. Distribution of solid holdup and the suspension uniformity were investigated. The results showed that there were some dense deposition in the bottom of tank when the rotational speed was lower than 600 r/min. As the rotational speed increased from 400 r/min to 1100 r/min, the accumulation height decreased from 0.16 to 0, the deposition area contracted and disappeared at last. Under the action of centrifugal force, the solid particles in the circulating flow moved toward far-vortex direction. Solid holdup at the center of vortex was lower, so the suspension uniformity was drastically reduced. The two-phase flow could be divided into upper and lower circulation regions at the height of z/H=1/3. The distribution of particles was affected by the confluence of circulating flow, and the solid phase was dispersed with the flow field in the radial direction. Suspension uniformity tends to be stable at 0.5~0.7 with the increase of the height. As the rotational speed increased from 400 r/min to 1100 r/min, the value of σ in the upper circulation regions decreased by 37.2%.

Key words: solid?liquid suspension, stirred tank, solids holdup distribution, suspension uniformity, numerical simulation

中图分类号: