微通道气液柱塞流头部流场三维实验研究

为研究微通道气液柱塞流三维流场特性,采用三维Micro PIV技术对微通道气液柱塞流进行实验研究,通过处理分析柱塞流图像,获得气泡前部区域的示踪颗粒分布图和三维速度分布图.研究结果表明:在气泡前部区域存在两个对称的方向相反的漩涡;在气柱头部附近区域,流体以较大速度沿着气柱表面流动;在远离气柱头部的区域,与单相流有类似的抛物线速度分布;在气液界面和壁面之间的流体运动复杂,有可能流向气液界面,也有可能流向壁面,气液界面近似为刚性. 

Experimental Investigations of Three-Dimensional Flow Field around the Head of Gas-Liquid Slug Flow in Microchannels

The three-dimensional micro-particle image velocimetry (PIV) technique was used for experimentally studying three-dimensional flow field properties of slug flow in microchannels. By processing images of slug flow, three-dimensional fluorescent particles distribution and velocity flow field of the liquid around the head of slug bubble was obtained. The results show that there was two symmetrical and reverse vortices near the head of the bubble. The fluid near the bubble head had a larger velocity and flowed along the bubble surface. In the flow field far away from the bubble, the distribution of liquid velocity was parabolic in the radial direction, which was similar to a single-phase pressure driven flow. The fluid between the bubble surface and the microchannel walls had a complex motion: it might be pushed to the bubble tip if closer to the bubble surface or might be passed if closer to the walls. In addition, the gas-liquid interface was approximately rigid.