并联硅基扩缩微通道内气液两相间歇流型与压降特性

采用以IDT高速摄像仪和Nikon生物显微镜为主体的可视化观测系统,实验研究并联硅基扩缩微通道内氮气/水气液两相间歇流型及压降特性.随气液两相表观流速变化,间歇流子流型依次呈现环状/单相液体交替流型、弹状/环状/单相液体交替流型、弹状/单相液体交替流型、雾状/弹状/单相液体交替流型和雾状/单相液体交替流型,得到不同气液两相表观流速下并联扩缩微通道流型分布图.研究表明,均相流模型的压降计算结果同实验值有较大出入.尽管分相流模型在一定程度上引入了气液两相的相互作用,其预测结果好于均相流模型,但是仍无法精确地描述并联扩缩微通道内氮气/水气液两相的运动与空间分布.

Intermittent Flow Pattern and Pressure Drop for Two-phase Flow in Parallel Microchannels With Expansion-constriction Cross Sections

The gas-liquid two-phase intermittent flow pattern and pressure drop characteristics in parallel microchannels with expansion-constriction cross sections were investigated experimentally by means of the IDT high-speed camera mounted together with a Nikon microscope.The results showed that,with the change of the gas-liquid two-phase superficial velocity,the annular/liquid alternating flow pattern,the slug/annular/liquid alternating flow pattern,the slug/liquid alternating flow pattern,mist/slug/liquid alternating flow pattern and mist/liquid alternating flow pattern presented in turn.The two-phase flow regime maps for the parallel microchannels with expansion-constriction cross sections were obtained.The homogeneous flow model cannot predict the two-phase pressure drop data.Despite the separated flow model introducing the gas-liquid two-phase interaction to a certain extent,the gas-liquid two-phase movement and space distribution in the parallel microchannels with periodic expansion-constriction cross sections cannot be predicted accurately.