Experimental study on liquid-liquid two-phase flow pattern and flow characteristics in sinusoidal microchannels

doi:10.11949/0438-1157.20211013

Abstract

Abstract:

Experimental methods are used to analyze the flow characteristics of droplets of immiscible liquid-liquid two-phase fluid in sinusoidal microchannels with different inlet structures, including straight channel sine, wave crest sine, and the middle of the wave. Silicone oil is used as the dispersed phase, and distilled water containing 0.5% SDS is used as the continuous phase. Slug, droplet and jet flow are observed in the experiments. Effects of two-phase flow parameters and different microchannel inlet structures on the flow pattern and droplet length are analyzed. The flow pattern is greatly affected by the microchannel inlet structure, and the wave crest sinusoidal microchannel can generate the largest range of stable flow patterns than the other two channels. The droplet length increases with the increase of the volume flow rate of the dispersed phase and the ratio of the volume flow rate of the dispersed phase to that of the continuous phase, and decreases with the increase of the volume flow rate of the continuous phase and the capillary number. The inlet structure of the microchannel has influence on the length of the droplet. The length of the droplet in the sinusoidal microchannel with a straight channel inlet is the shortest, which is more conducive to the formation of droplets. Among the droplets generated by the three channels, the largest droplet size is 1.15-1.39 times larger than the smallest droplet size. The sinusoidal structure of the microchannel has almost no effect on the droplet velocity compared with the straight channel.

Key words: microchannels, two-phase flow, inlet structure, flow pattern, capillary number

摘要：

采用实验的方法对不混溶的液液两相流体在不同入口结构下的正弦微通道(直通道正弦、波峰正弦和波中正弦)内液滴的流动特性进行了分析。硅油作为离散相，含有0.5% SDS的蒸馏水作为连续相，观测到弹状流、滴状流和射状流。分析了两相流动参数及不同的微通道入口结构对流型和液滴长度的影响。流型受微通道入口结构影响较大，波峰正弦微通道能够生成最大范围的稳定的流型。液滴长度随离散相体积流量和离散相与连续相体积流量之比的增大而增大，随连续相的体积流量和毛细数的增大而降低。微通道入口结构对液滴长度有影响，直通道的正弦微通道内液滴长度最短，更有利于液滴的形成。三种通道生成的液滴中，最大的液滴尺寸是最小的液滴尺寸的1.15~1.39倍，但正弦流动段对液滴速度几乎没有影响。

关键词: 微通道, 两相流, 入口结构, 流型, 毛细数

CLC Number:

TK 124

Jingzhi ZHANG, Yuting ZHAO, Yingdi WANG, Jianhui QI, Li LEI. Experimental study on liquid-liquid two-phase flow pattern and flow characteristics in sinusoidal microchannels[J]. CIESC Journal, 2022, 73(3): 1111-1118.

张井志, 赵玉婷, 王英迪, 齐建荟, 雷丽. 正弦型微通道内液-液两相流型及流动特性实验研究[J]. 化工学报, 2022, 73(3): 1111-1118.

Figures/Tables 8

Fig.1 Schematic diagram of experimental system and microchannel

Table 1 Fluid properties

流体系统		μ/(Pa·s)	ρ/(kg/m³)	γ/(N/m)
连续相	0.5% (mass) SDS	0.00135	971.53	—
离散相	silicone oil	0.01	901.4	0.0118

Fig.2 Droplet formation process

Fig.3 Flow pattern and flow pattern transition line of experimental conditions in a straight channel sinusoidal microchannel

Fig.4 Flow pattern transition lines of different inlet structures

Fig.5 The influence of two-phase flow parameters on the length of droplets

Fig.6 The influence of microchannel inlet structure on droplet length

Fig.7 The influence of flow section structure of microchannel on droplet velocity

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