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Sensing and Actuation in Miniaturized systems Final report. Hello everyone !!!!! I am Wu Chih-Wei !!!!!. Outline. Introduction. Fabrication. System setup. Results and discussion. Conclusion. Outline. Introduction. Fabrication. System setup. Result and discussion. Conclusion. - PowerPoint PPT Presentation
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2009/1/6
Sensing and Actuation in Miniaturized systems
Final report
Hello everyone !!!!!
I am Wu Chih-Wei !!!!!
2009/1/6
2009/1/6
Outline
Introduction
Fabrication
System setup
Results and discussion
Conclusion
2009/1/6
Outline
Introduction
Fabrication
System setup
Result and discussion
Conclusion
2009/1/6
ACTUATED BY EWOD
PIV INVESTIGATION OF 3-DIMENSIONAL FLOW IN DROPS
Introduction
The change in contact angle due to an applied potential difference between solid and liquid
EWOD = Electrowetting-On-Dielectric
2009/1/6
PIV INVESTIGATION OF 3-DIMENSIONAL FLOW IN DROPS
Introduction
PIV = Particle Image Velocimetry
Flow direction
mirrorLaser
x
y
t t’
Image plane
2009/1/6
Introduction
PIV measurement in micro-channel flow!
2009/1/6
Outline
Introduction
Fabrication
System setup
Result and discussion
Conclusion
2009/1/6
Fabrication
cytop fluoropolymer
SiO2
ITO
Glass wafer
droplet
Secure seal
FEATURES: Leak-proof chambers are temperature resistant and eliminate evaporation
2009/1/6
Outline
Introduction
Fabrication
System setup
Result and discussion
Conclusion
2009/1/6
System setup
μPIV system
EWOD droplet actuation system
2009/1/6
System setup
2D velocity field near the mid-height of the drop
2009/1/6
Outline
Introduction
Fabrication
System setup
Result and discussion
Conclusion
2009/1/6
Result and discussion
50um100um150um200um250um300um350um
Entire stack of 2D velocity fields
computing
Continuity equation
(Local form of conservation equation)
Side view of the Droplet
Image plane 3D VELOCITY FIELDS!!!!
2009/1/6
Result and discussion
A strong downward flow due to the eletro-wetting from the bottom substrate is observed near the nose of the droplet
2009/1/6
Result and discussion
To understand net effect of the forward-back motions on mixing within the droplet
Measure the overall displacement of the first image from all PIV image pairs
Forward-back motion is inefficient for droplet mixing!!(reverse motion return the particles near their initial position)
2009/1/6
Outline
Introduction
Fabrication
System setup
Result and discussion
Conclusion
2009/1/6
Conclusion
1、 Our experimental finding shows the flow in a 3D droplet indeed deviates significantly from the parabolic flow profile used in current flow simulations
2、 It would be desirable to develop a reduced dimension model that is computationally tractable while preserving the essential information about the 3D velocity
3、 Due to the reversibility of the flow, a simple forward-back motion is inefficient for mixing , effective mixing has to be accomplished through irreversible movements.
2009/1/6
THANK YOU FOR YOUR ATTENTION!!!!
2009/1/6
Bonus Information!
Max Velocity: 120 um/s
UpMiddledown
100µm100µm
Channel wall
Channel wall
100 µm
Experimental Data by Y.L.Lin 2007