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Microfluidic Actuators. and Sensors. Dr. Eliphas Wagner Simoes (Post-Doc) Dr. Rogerio Furlan. Microfluidic amplifiers. 6 mm. 18 mm. No movable part Flow control Flow mixture. Microchannel Technology. Silicon wet etching - KOH - 27,4 % in water. Plasma etching - HDP plasma SF 6
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Microfluidic Actuators and Sensors • Dr. Eliphas Wagner Simoes (Post-Doc) • Dr. Rogerio Furlan
Microfluidic amplifiers 6 mm 18 mm • No movable part • Flow control • Flow mixture
Microchannel Technology • Silicon wet etching - KOH - 27,4 % in water • Plasma etching - HDP plasma SF6 • based - hidraulic diameters of ~ 40 µm • Anodic bonding- 377°C/ 800 V
Tests with gas (N2) Supply (S) Cut-off Valve 2 Cut-off Valve 1 Sensor 1 (flow) Sensor 2 (flow) Sensor 1 (flow) Sensor 6 (pressure) Sensor 7 (pressure) Sensor 8 (pressure) Control 2 (C2) Control 1 (C1) chip holder plate Vent 1 Vent 2 Sensor 4 (flow) Sensor 5 (flow) (O1) Output 1 (O2) Output 2
30 28 26 24 22 20 18 (sccm) 16 14 12 O1 10 Q 8 6 4 2 0 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 Q (sccm) C1 Flow control results QS QC1 QO1 QO2 • Symmetrical behavior • Non-zero output
Flow gain (DQO/DQC) results • High flow gain: up to 8
a Flow ratio results • More uniform performance for small splitter angles
Analysis of internal flow with Ansys/Flotran • Choked flow at the output of the supply nozzle
Analysis of internal flow with Ansys/Flotran • Supersonic flow at the interaction region • Possibility of shock waves formation
Analysis of internal flow with Ansys/Flotran • Laminar to turbulent flow • Continuum to slip flow
Main results for use with gas • Feasibility for applications that require gas flow control • Gain flow comparable to the obtained to devices with large dimensions • Possibility of operation with internal disturbances (shock waves and turbulence) - application as flow mixer • Good basis for development of microfluidic oscillators for flow sensor applications
Microfluidic oscilattor • Flow Measurement
Tests with liquids • Supply flow: • Isopropilic alcohol • Acetone • Distilled water • Control flow: • Nitrogen • Liquids
Increasing control flow Supply of liquids with nitrogen control • Possibility of control for alcohol and acetone • Influence of viscosity, bubbles and hydrophobic effects for water • Increasing supply flow
Increasing control flow Supply of liquids with liquid control • Possibility of control for alcohol • Pronounced formation of bubbles for acetone and water • Flow throughout vents (Coanda Effect?) • Increasing supply flow
Rapid prototyping of microfluidic switches in poly(dimethyl siloxane)and their actuation by electro-osmotic flow J. Micromech. Microeng. 9 (1999) 211– 217 - Department of Chemistry and Chemical Biology, Harvard University
Main results for use with liquids • Promising results for control with gas • Strong influence of the type of liquid (viscosity) • Possibility of hydrophobic effects - points to use of other materials and processes • Can be operated with some level of suspended solids without clogging