Miniaturized fluidic systems like MEMS may involve single-phase or multi-phase flows with oscillations/ pulsations. Understanding the hydrodynamics of such flows can help in manipulating the performance parameters and improving the efficiency of micro-systems. This work focuses on hydrodynamics of a sinusoidally oscillating meniscus in a square mini-channel. The interfacial contact line behavior of a single oscillating meniscus formed between liquid slug and air, inside the square capillary tube, has been explored. An eccentric cam follower system has been fabricated to provide sinusoidal oscillations of fluid in the square glass capillary having hydraulic diameter of 2.0 mm. Experiments are conducted with two fluids, water and silicon oil. Dynamic contact angle measurements are carried out for water at two oscillating frequencies, 0.25 Hz and 0.50 Hz using high speed videography. It is seen that an increase in the oscillating frequency increases the difference in the advancing angle and receding angle of the meniscus, with the static contact angle of water on glass surface around 21°. For silicon oil the experiments have been performed at eight different frequencies in the range of 0.20 Hz and 1.00 Hz. It is seen that the meniscus is pinned at the extreme end of the stroke, unlike that in the case of water, and there is a film of silicon oil during oscillations. The thickness of the film formed increases with increase in oscillating frequency. There is considerable difference in the hydrodynamics of silicon oil and water.
- Nanotechnology Institute
Hydrodynamic Study of an Oscillating Meniscus in a Square Mini-Channel
Shekhawat, YS, Khandekar, S, & Panigrahi, PK. "Hydrodynamic Study of an Oscillating Meniscus in a Square Mini-Channel." Proceedings of the ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer. ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer, Volume 2. Shanghai, China. December 18–21, 2009. pp. 679-684. ASME. https://doi.org/10.1115/MNHMT2009-18322
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