刚性/柔性桨叶作用的湍流液液分散体系的液滴尺寸与分布  

Study on droplet size and distribution in turbulent liquid-liquid dispersion with rigid/flexible impellers

作　　者：袁铭扬 徐佳伟 曾宏伟 陈律名 张玮[1] 陈冰冰[1] YUAN Ming-yang;XU Jia-wei;ZENG Hong-wei;CHEN Lyu-ming;ZHANG Wei;CHEN Bing-bing(College of Mechanical Engineering,Zhejiang University of Technology,Hangzhou 310023,China)

机构地区：[1]浙江工业大学机械工程学院,浙江杭州310023

出　　处：《高校化学工程学报》2022年第3期371-379,共9页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金(21908195)。

摘　　要：为提高搅拌槽内不溶液液两相的分散效果,将柔性桨叶应用于油/水分散系统以替代传统刚性搅拌桨,并通过摄影法获得系统内液滴尺寸与分布,探究了桨叶类型和分散相体积分数对液滴平均直径和液滴尺寸分布(DSD)的影响。结果表明:柔性桨叶系统内液滴平均直径比刚性系统减小了20%~25%,柔性系统内液滴尺寸更加均匀,DSD曲线更接近对数正态分布,而刚性系统DSD则遵循正态分布。随着分散相体积分数的增加,基于Hinze-Kolmogorov理论的液滴尺寸预测模型中的韦伯数We指数有增大趋势,新模型对传统经验关联式进行改进,预测结果与实验数据吻合度较高,平均相对误差小于3%。In order to improve mixing performance of immiscible liquid-liquid dispersion in stirred tanks,flexible impeller was employed to replace traditional rigid impeller for oil-in-water emulsion agitation.Size and distribution of dispersed droplets in the mixing process were studied via imaging.Effects of impeller type and dispersed phase volume fraction on the mean droplet size and droplet size distribution(DSD)were investigated.The results show that d32 predicted in the stirred tank equipped with the flexible impeller is decreased by 20%to 25%comparing with that of rigid impeller.Uniform droplet size distribution is observed with flexible impeller.DSD of flexible impeller presents a lognormal distribution,while normal distribution is obtained for rigid impeller.An increase of exponent of Weber number in the droplet size prediction model based on Hinze-Kolmogorov theory was observed when the dispersed phase volume fraction was increased.The new empirical correlation can provide better droplet size predictions in a stirred tank than traditional ones.The average relative error between the new correlation prediction and the experimental results is less than 3%.

关 键 词：柔性桨叶 液液分散 液滴平均直径 滴径尺寸分布 

分 类 号：TQ027.2[化学工程]