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 Setup Top View Diagram DC Power Supply High Voltage Plasma Generator Smoke Generator Power Supply Digital Camera Glass Channel Electrodes Kapton Tape Heating Element

Project Setup Channel Models Large Channel 2.54 cm by 1.4 cm Small Channel: 2 mm by 2 mm

Results Velocity Measurements

No noticeable change in flow velocity with change in geometry.

Results Dielectric Experimentation 2 mil Kapton tape –dielectric strength of 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.

Results Flow Direction and Path Used opposing electrode pairs to demonstrate control of flow direction in a 2 mm by 2 mm channel. Independent electrode control.

Results Flow 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 Research MEMS 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