液-液萃取过程中液滴分散特性的数值模拟

Numerical Simulation of Droplet Dispersion in Liquid-liquid Mixing Chamber

多级混合澄清槽中,液、液两相间的分散和凝并决定萃取级效率。应用计算流体力学软件对比液-液萃取混合澄清槽采用的大三角型桨与闭式涡轮桨的混合效果,并耦合群体平衡模型,模拟混合室内分散相滴径分布,以水和煤油为试验介质进行验证。结果表明,混合室搅拌器采用大三角型桨能够产生更好的总体混合效果,油相局部相含率分布更加均匀,但闭式涡轮桨可以形成更加细小的油滴。

In multistage mixer-settlers,the extraction efficiency is dependent on efficient dispersion and coalescence between continuous and liquid phase.In order to compare the mixing efficiency of the large triangle impeller and the closed turbine propeller,a computational fluid dynamics(CFD)simulation coupled with population balance model(PBM)is applied to simulate the droplet size distribution of dispersed phase in the mixing chamber.The simulation method is validated by experiments in which water and kerosene are continuous phase and dispersed phase,respectively.The results show that better overall mixing and more uniform distribution of dispersed oil droplets can be obtained by the large triangle impeller,but the closed turbine propeller can produce more tiny oil droplets.