不溶液-液分散在搅拌槽内的CFD模拟

摘要

液滴平均尺寸和液滴尺寸分布是描述不溶液-液分散程度的2个重要参数，决定着两相接触面积的大小，进而决定着相间的传质、传热和化学反应速率。利用CFD方法详细研究了水-油两相在搅拌槽内的分散过程，发现叶轮转速、分散相体积分数和连续相黏度对分散效果有显著影响。当两相组成一定时，增大叶轮转速和连续相黏度均有利于两相的分散。在一定范围内，液滴平均直径与叶轮转速、分散相体积分数均为对数线性关系，相关系数高达0.999。基于个数的液滴尺寸分布在不同转速和连续相黏度条件下出现了双峰分布，而基于体积的液滴尺寸分布则始终为单峰分布。

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	闫越飞
	王日杰
	杨晓霞

关键词：平均液滴尺寸；液滴尺寸分布；不溶液-液分散；搅拌槽； CFD

Abstract：

The mean droplet size and droplet size distribution are two important parameters for the description of immiscible liquid-liquid dispersion. They are closely related to the contact areas between the two phases which determine the rates of mass and heat transfer and chemical reactions. This work investigated the water-oil dispersion within a stirred tank using CFD method in detail. Results show the dispersion is significantly affected by the impeller speed, dispersed phase volume fraction and continuous phase viscosity. The increase of impeller speed and continuous phase viscosity is beneficial to dispersion when the composition of two phases was constant. The plots of mean droplet size versus impeller speed and that of mean droplet size versus dispersed phase volume fraction give good log-linear correlations, and the relative coefficients are up to 0.999. Besides, the droplet size distributions based on number are found to have bimodal distribution with the variation of impeller speed and continuous phase viscosity, while the droplet size distributions based on volume are unimodal distribution all the time.

Keywords： mean droplet size； droplet size distribution； immiscible liquid-liquid dispersion； stirred tank； CFD

Received 2016-03-15;

Corresponding Authors: 杨晓霞,E-mail:xxy@tju.edu.cn。 Email: xxy@tju.edu.cn

About author: 闫越飞(1986-),男,硕士研究生,现从事化工搅拌过程的仿真模拟研究。

引用本文:

闫越飞, 王日杰, 杨晓霞.不溶液-液分散在搅拌槽内的CFD模拟[J]. 化学工业与工程, 2018,35(2): 70-79

Yan Yuefei, Wang Rijie, Yang Xiaoxia.CFD Simulation of Immiscible Liquid-Liquid Dispersion in a Stirred Tank[J]. Chemcial Industry and Engineering, 2018,35(2): 70-79

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