Determination of droplet contours in liquid-liquid flows within microchannels

[摘要] An experimental analysis of the droplet regime with a silicone oil-water two-phase flow within a micro cross-junction, varying the average velocity of the fluids, has been carried out. The micro cross-junction is made as intersection of two glass microchannels with a stadium-shaped cross-section with height H=190 μm and width Wj=195 μm within the junction and W=390 μm before and after the junction. The water flow rate is broken in droplets having spherical shape with dimensions and velocity that depend on the average velocity ratio imposed. Different kinds of intermittent droplets have been observed, in the ranges of average velocity (0.0105-0.042) m/s and (0.0004-0.0050) m/s for oil and water, respectively. The droplet velocity has been calculated starting from the detection of the shape of the droplets and then by the evaluation of the displacement of the droplets in the unit of time. The images of the droplets have been obtained from a high-speed camera, connected to an inverted microscope. The procedure of water phase contour detection is based on Matlab Image Toolbox scripts.

[发布机构] DIN - Alma Mater Studiorum Universitá di Bologna, Laboratorio di Microfluidica, Via del Lazzaretto 15/5, Bologna; 40131, Italy^1

[效力级别] 力学 [学科分类] 力学，机械学

[关键词] Average velocity;Contour detection;Droplet velocity;Experimental analysis;Glass microchannels;Liquid-liquid flow;Spherical shape;Water flow rate