| 1. |
- Carlborg, Carl Fredrik, et al.
(author)
-
Continuous flow switching by pneumatic actuation of the air lubrication layer on superhydrophobic microchannel walls
- 2008
-
In: 21st IEEE International Conference on Micro Electro Mechanical Systems (IEEE MEMS 2008). - : IEEE conference proceedings. - 9781424417926 ; , s. 599-602
-
Conference paper (peer-reviewed)abstract
- This paper introduces and experimentally verifies a method for robust, active control of friction reduction in microchannels, enabling new flow control applications and overcoming previous limitations with regard to sustainable liquid pressure. The air pockets trapped at asuperhydrophobic micrograting during liquid priming are coupled to an actively controlled pressure source, allowing the pressure difference over the air/liquid interface to be dynamically adjusted. This allows for manipulating the friction reduction properties of the surface, enabling active control of liquid mass flow through the channel. It also permits for sustainable air lubrication at theoretically unlimited liquid pressures, without loss of superhydrophobic properties. With the non-optimized grating used in the experiment, a difference in liquid mass flow of 4.8 % is obtained by alternatively collapsing and recreating the air pockets using the coupled pressure source, which is in line with a FE analysis of the same geometry. A FE analysis of a more optimized geometry predicts a mass flow change of over 30%, which would make possible new microfluidic devices based on local friction control. It is also experimentally shown that our method allows for sustainable liquid pressure 3 times higher than the Laplace pressure of a passive device.
|
|
| 2. |
- Do-Quang, Minh, et al.
(author)
-
Numerical Simulation of the Passage of Small Liquid Droplets Through a Thin Liquid Film
- 2008
-
In: PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON NANOCHANNELS, MICROCHANNELS, AND MINICHANNELS. - NEW YORK : AMER SOC MECHANICAL ENGINEERS. - 9780791848340 ; , s. 857-861
-
Conference paper (peer-reviewed)abstract
- We simulate numerically a novel method for dispensing, mixing and ejecting of picolitre liquid samples in a single step. The system consists of a free liquid film, suspended in a frame and positioned in front of a droplet dispenser. On impact, a picolitre droplet merges with the film, but due to its momentum, passes through and forms a droplet that separates on the other side and continues its flight. Through this process the liquid in the droplet and that in the film is mixed in a controlled way. We model the flow using the Navier Stokes together with the Cahn-Hilliard equations. This system allows us to simulate the motion of a free surface in the presence of surface tension during merging, mixing and ejection of droplets. The influence of dispensing conditions was studied and it was found that the residual velocity of droplets after passage through the thin liquid film matches the measured velocity from the experiment well.
|
|
| 3. |
- Gey, Laurent, et al.
(author)
-
STUDY OF THE FLIGHT OF SMALL LIQUID DROPLETS THROUGH A THIN LIQUID FILM FOR PICOLITRE LIQUID TRANSFER
- 2006
-
In: 19th IEEE International Conference on Micro Electro Mechanical Systems (IEEE MEMS 2006). - New York : IEEE conference proceedings. - 0780394755 ; , s. 24-27
-
Conference paper (peer-reviewed)abstract
- We introduce and successfully demonstrate a novel method and system for subsequent dispensing, mixing and ejecting of picolitre liquid samples in a single step. The system consists of a free liquid film, suspended in a frame and positioned in front of a droplet dispenser. In this study we tested and modelled the flight of liquid droplets, ejected from an inkjet print head, through a suspended liquid film. Model and experiment are in accordance.
|
|
