摘要
现有的针对液-固两相搅拌体系临界转速的研究多集中于低固含率体系,但工业中的高固含率体系十分常见。采用计算流体力学(CFD)方法对高固含率搅拌罐内的液-固两相流体流动进行了数值模拟,实现了对高固含率固-液搅拌罐内液固流动行为的直观预测,研究了颗粒物性(颗粒尺寸、颗粒密度)对颗粒悬浮特性的影响,结果表明,随着颗粒尺寸或颗粒密度的增加,颗粒的悬浮高度逐渐降低,最大固相体积分率增大。基于CFD方法的完全离底悬浮临界搅拌转速的预测方法,得到了高固含率搅拌罐内不同颗粒物性下关键参数离底悬浮临界转速Nc的变化规律:Nc随着固液密度差的增加而增加,随着颗粒直径的增加而增加;变化规律可用公式表示为:N_(c)^(∝)(ρ_(s)-ρ_(l))^(0.751 7),N_(c)^(∝)(d_(s))^(0.934 3)。
The existing research on the critical speed of liquid-solid two-phase stirring system mostly focuses on the low solid holdup system,but the high solid holdup system in industry is very common.Computational fluid dynamics(CFD)method was used to simulate the liquid-solid two-phase fluid flow in the stirred tank with high solid holdup,to realize the intuitive prediction of the liquid-solid flow behavior in the stirred tank with high solid holdup,and to study the influence of particle properties(particle size,particle density)on particle suspension characteristics.The results showed that with the increase of particle size or particle density,the suspension height of particles gradually decreased and the maximum solid volume fraction increased.Based on the prediction method of the critical stirring speed of complete off-bottom suspension based on CFD method,the change rule of the key parameter of off-bottom suspension critical speed Nc under different particle properties in the stirred tank with high solid content was obtained:Nc increases with the increase of solid-liquid density difference,and increases with the increase of particle diameter;The law of change could be expressed as:N_(c)^(∝)(ρ_(s)-ρ_(l))^(0.751 7),N_(c)^(∝)(d_(s))^(0.934 3).
作者
周延红
刘胜军
龚浩
董贺
孟芳
Zhou Yanhong;Liu Shengjun;Gong Hao;Dong He;Meng Fang(Xinjiang TianyeHuixiang New Materials Co.,Ltd.,Shihezi,Xinjiang 832061,China;R&D Center for Petrochemical Technology,Key Laboratory for Green Chemical Technology of the Ministry of Education,Tianjin University,Tianjin 300072,China)
出处
《化工设备与管道》
CAS
北大核心
2023年第1期48-54,共7页
Process Equipment & Piping
关键词
搅拌罐
颗粒悬浮
CFD
固相体积分率
临界转速
高固含率
stirred tank
particle suspension
CFD
solid volume fraction
critical speed
high solid holdup
