Experimental Techniques for Bubble Dynamics Analysis in Microchannels: A Review

Abstract

Experimental studies employing advanced measurement techniques have played an important role in the advancement of twophase microfluidic systems. In particular, flow visualization is very helpful in understanding the physics of twophase phenomenon in microdevices. The objective of this article is to provide a brief but inclusive review of the available methods for studying bubble dynamics in microchannels and to introduce prior studies, which developed these techniques or utilized them for a particular microchannel application. The majority of experimental techniques used for characterizing twophase flow in microchannels employs highspeed imaging and requires direct optical access to the flow. Such methods include conventional brightfield microscopy, fluorescent microscopy, confocal scanning laser microscopy, and micro particle image velocimetry (microPIV). The application of these methods, as well as magnetic resonance imaging (MRI) and some novel techniques employing nonintrusive sensors, to multiphase microfluidic systems is presented in this review.