Mixed state of liquid and gas is frequently seen in fluidic MEMS, for example, ink jet printer, heat exchanger, thermo-capillary optical switch, and so on. The surface tension is the most dominant mechanical effect in such microscale liquid-gas systems. However, there is no reliable scheme for the bubbly flow especially in a microchannel. In this paper, a new numerical scheme is developed based on C-CUP and Level-Set method with CSF model in order to calculate the liquid/gas interface and surface tension distribution precisely. The key of this new Lagrange-type scheme is the modeling of surface tension force on the extremely thin interface. By using this scheme, the thermo-capillary motion of bubble or droplet in a microchannel is analyzed, which is also investigated by experiments using MEMS-based system of microheater in a microchannel. It is the first time to successfully simulate the thermally-driven interface in a microchannel and the obtained results show good agreements with experimental data qualitatively. Comparisons with the conventional numerical schemes and fundamental mechanisms of force transfer at the contact point on solid wall are discussed.
Journal: TechConnect Briefs
Volume: 1, Technical Proceedings of the 2003 Nanotechnology Conference and Trade Show, Volume 1
Published: February 23, 2003
Pages: 182 - 185
Industry sectors: Medical & Biotech | Sensors, MEMS, Electronics
Topic: Micro & Bio Fluidics, Lab-on-Chip