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Using a Microplasma for
Propulsion in Microdevices
David Arndt
Faculty Mentors: Professor John LaRue and Professor
Richard Nelson
IM-SURE 2006
Outline
• Plasma Pump Introduction• Project Goals• Background• Project Setup and Description• Results• Summary• Future Research Plans
Plasma Pump Introduction
• Air is ionized to create a plasma.
• Ions move in response to an electric field.
• Impart force onto surrounding air molecules
Copper Electrodes
Kapton Tape
Airflow
Project Goals
• Create a working macro-scale plasma pump• Visualize flow• Evaluate effect of changing experiment
parameters in order to optimize setup• Control electrodes independently in order to
control flow direction and path.• Design and fabricate a MEMS device that
implements a microplasma pump.
Background
• General Micropump Applications – Manipulating micro-particles and micro volume
fluids.
• Types of micropumps – Reciprocating: peristaltic pump – Continuous flow: electrophoresis pump
• Plasma Micropump Applications– Manipulating gas-carried particles– Gas sensor– MEMS cooling
Background
• Inspiration for our Plasma Pump Research: “Using Plasma Actuators For Separation Control on High Angle of Attack Airfoils,” Martiqua L. Post et al.
Project SetupTop View Diagram
DC Power Supply
High Voltage Plasma Generator
Smoke Generator Power Supply
Digital Camera
Glass Channel
Electrodes
Kapton Tape
Heating Element
Project SetupChannel Models
Large Channel
2.54 cm by 1.4 cm
Small Channel:
2 mm by 2 mm
ResultsVelocity Measurements
ResultsVelocity Measurements
3 mm overlap - both electrodes 20 mm wide - exponential fit
0
5
10
15
20
25
30
0 1 2 3 4 5
position (cm)
velo
city
(cm
/s)
Setup 4 - top electrode 3 mm wideexponential fit
0
5
10
15
20
25
-2 0 2 4 6 8
position (cm)
velo
city
(cm
/s)
Setup 5 - Top electrode 12 mm wideexponential fit
0
5
10
15
20
25
30
0 1 2 3 4 5 6 7 8
position (cm)
velo
city
(cm
/s)
No noticeable change in flow velocity with change in geometry.
ResultsDielectric Experimentation
• 2 mil Kapton tape– dielectric strength of 12000 volts.– 1 layer: minimum voltage enough to burn
Kapton– 3 layers: works well, very little damage
• 6 mil Cover glass: no noticeable damage– will be used in MEMS device.
ResultsFlow Direction and Path
• Used opposing electrode pairs to demonstrate control of flow direction in a 2 mm by 2 mm channel.
• Independent electrode control.
ResultsFlow Direction and Path
•Control of Flow Path in a Bifurcating Channel
Summary
• Created macro-scale plasma pump and visualized air flow.
• Evaluated the effect of electrode width, electrode overlap and dielectric material/thickness.
• Demonstrated control of flow path and direction
Future ResearchMEMS Plasma Pump Design and Fabrication
• Overlapping electrodes• Slide cover glass as dielectric• Electrodes created by electron beam
deposition and photolithographic patterning• Channel formed by patterning a clear silicone
material• Introduce visualization smoke using a
hypodermic needle or create internally
Acknowledgements
Project direction:
Professors John LaRue and Richard Nelson
Technical expertise and advice:
Allen Kine and George Horansky
Research Team:
Eric Cheung, Michael Peng, and Patrick Nguyen Huu
