旋流器内油滴聚并破碎与粒径分布的数值模拟

Numerical Simulation of Oil Droplets Coalescence and Breakage and Particle Size Distribution on Hydrocyclone

为探究旋流器内油滴破碎聚并与粒径分布规律,该文采用欧拉-欧拉多相流模型、雷诺应力模型和群体平衡模型,对不同粒径组下油滴的体积浓度和粒径分布进行了模拟,并选取模拟其中一粒径组,分析了在轴向和径向上的分布规律。结果表明,在离散相体积浓度范围不变的情况下,分离效率在一定范围内随着入口油滴粒径的增大而提高;湍流能量耗散与油滴体积浓度成反比,在所有分离区域中,湍流能量耗散小的大锥段,油滴的体积浓度最大、油滴粒径上限较大,而小锥段则相反;从壁面到轴心,小粒径油滴由破碎产生占主导转变为聚并消失占主导,而大粒径油滴由破碎消失占主导转变为聚并产生占主导。

In the aim of exploring the coalescence and breakage and particle size distribution of oil droplets on hydrocyclone.Using the Euler-Euler Multiphase model and the reynolds stress model(RSM)and the population balance model(PBM),the volume concentration and particle size distribution of oil droplets under different particle sizes groups were simulated.In the same time,one of the particle size groups were simulated to analyse the distribution law in the axial and radial directions.The results show that when the volume concentration range of discrete phase remains unchanged,the separation efficiency increases with the increase of inlet particle size within a certain range.The turbulent energy dissipation is inversely proportional to volume concentration of oil droplets.Among all the separation regions,the big cone segment with small turbulent energy dissipation has the largest volume concentration and the upper limit of droplet size is big too,while the small cone segment has the opposite effect;From the wall surface to the axis,oil droplets with small particle size changed from coalescence to breakage,while oil droplets with large particle size changed from breakage to coalescence.