【摘要】 为了研究凹穴型结构对微通道内液-液两相流动特性的影响,利用高速摄像机,结合边缘检测算法(Canny),获得两相流型、液滴长度和膨胀面积等参数。结果表明:基于无量纲液滴长度参数,凹穴微通道内流型主要为膨胀流、过渡流及滴状流。随两相体积流量的增大,液滴长度逐渐减小,流型由膨胀流逐渐转换为过渡流,当液滴长度小于通道宽度时,凹穴结构对液滴形状的影响可以忽略。凹穴型通道内的液滴长度呈周期性变化,长度变化振幅为平直段的3～5.6倍。无量纲液滴膨胀面积随离散相与连续相流量之比的增大逐渐增大,随连续相毛细管数增大而逐渐降低。更多还原

【Abstract】 In order to study the effect of reentrant cavities on characteristics of liquid-liquid two-phase flow in microchannels, a high-speed camera together with edge detection algorithm(Canny) was adopted to obtain parameters such as flow pattern, droplet length, and dimensionless expansion area. The results show that the flow pattern can be categorized as expanding flow, transition flow, and droplet flow following the dimensionless droplet length in microchannels with reentrant cavities. Droplet length gradually decreased with the increase of volume flow rates of the two phases, and the flow pattern in the microchannel gradually changed from expanding flow to transition flow. When the droplet length was smaller than the channel width, the effect of cavities on droplet shapes was negligible. Droplet lengths in the reentrant cavities microchannel changed periodically. The amplitude of fluctuation in reentrant cavities microchannel was 3 to 5.6 times of that in the straight channel. Dimensional droplet expansion area increased with the increase of volume flow rate ratio of dispersed phase to continuous phase, and decreased with the increase of the continuous phase capillary number.更多还原