液-固-固三相流搅拌槽内流动特性研究

Study on Flow Characteristics in Liquid-Solid-Solid Three-Phase Flow Stirring Tank

采用计算流体动力学方法,通过欧拉多相流模型对螺杆-挡板搅拌槽内的某液-固-固三相流进行速度场、密度场和各相体积分数分布进行研究。结果表明,在原始的螺杆-挡板式搅拌桨作用下,多相流整体流动性和湍流特性均不太明显,近壁区易形成高密度聚集现象。增设辅助螺杆桨后,湍流现象明显增强,促进了各区域流体的混合对流;近壁区各相体积分数偏离设定值较小,偏差为±5%;中间区域各相体积分数相对稳定,且与设定数值更接近,偏差为±2%,整体而言,混合均匀化效果更好,有效避免了搅拌死角。研究结果对多相流流动特性分析和搅拌装置优化设计具有一定的参考意义和理论价值。

The computational fluid dynamics(CFD)method is used to study the velocity field,density field and volume fraction distribution of liquid-solid-solid three-phase flow in a screw-baffle agitation tank by Euler multiphase flow model.The results show that under the action of the original screw-baffle paddle,the overall fluidity and turbulence characteristics of multiphase flow are not obvious,and the high density aggregation is easy to form in near-wall area.After the auxiliary screw paddle is added,the turbulence phenomenon is enhanced obviously,which promotes the mixed convection of the fluids in each region;the volume fraction of each phase in the near-wall area deviates from the set value by a small value and the deviation is±5%;the volume fraction of each phase in the middle area is relatively stable and closer to the set value,and the deviation is±2%.Overall,the mixing uniformization effect is better,and the stirring dead angle is avoided effectively.The research results of this paper have certain reference significance and theoretical value for the analysis of multiphase flow characteristics and optimization design of stirring device.