Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
148524 | Chemical Engineering Journal | 2013 | 7 Pages |
In addition to the generation of micrometer scaled droplets, microchannel device can also serve as unique platform to control microdroplet coalescence. In this study, a cross-shaped microchannel junction is designed to realize head-on microdroplet coalescence without strict control of droplet synchronism. The flow characters of contacting microdroplets in confined microchannels are carefully examined and a critical capillary number (Ca∗ ≈ 0.005) for the occurrence of coalescence is identified for different working systems. Experimental analysis on the film drainage time and the droplet contact time are carefully discussed and a comparison between microdroplet coalescences in confined and free flowing spaces are taken for the in-depth understanding of microdroplet coalescence process.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Head-on microdroplet coalescence is obtained without synchronism control. ► The critical Ca for microdroplet coalescence is identified as 0.005. ► The critical Ca is larger in confined microchannel than in free flowing space.