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为了确定微通道中气液两相传质过程中流动体系的比表面积a以及液相传质系数k_L,以此来确定工艺设计及操作的具体参数。本文利用高速摄像系统对微通道中二氧化碳-蒸馏水传质过程Taylor气泡的变化过程进行了测定,并利用自编图像处理软件和MATLAB软件编程计算得到了流动体系的比表面积a。结果显示,a随着气相流速的增大而增大,但随着液相流速的增加,有所减小,且较常规通道中的比表面积大1~2个数最级。利用k_La预测公式计算得到了液相传质系数k_L,在微通道中的k_L数值与常规管道中的数值基本一致,k_L数值几乎不随着气相流速的改变而变化,在相同的气相流速下,随着液相流速的增加而有所增大。
In order to determine the specific surface area a of the flow system and the liquid mass transfer coefficient k_L during gas-liquid two-phase mass transfer in the microchannel, the specific parameters of the process design and operation are determined. In this paper, the change of Taylor bubble in the process of mass transfer of carbon dioxide-distilled water in microchannels was measured by high-speed camera system. The specific surface area of the flow system was calculated by self-programmed image processing software and MATLAB software. The results show that a increases with the increase of the gas velocity, but decreases with the increase of the liquid velocity, and the most specific surface area is 1 to 2 more than the conventional channels. The mass transfer coefficient k_L was calculated by k_La prediction formula. The value of k_L in microchannels was basically the same as that in conventional pipelines. The value of k_L hardly changed with the change of gas flow rate. With the same gas phase flow rate, With the increase of liquid flow rate has increased.