S.Loire: Study of AC electrothermal Fluid Flow Models

Mezić Research GroupDynamical Systems and Nonlinear Control Theory

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Motivation: Microfluidic manipulation

• Fully integrated lab on chip• Mixing, concentration, pumping, separation of fluids and

particles in microchannels• Example: Mixing for bioassays

goal: Improve reaction rate in traditional and microarray biosensors via mixing.


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• Solution: Integrated electrodes generating AC electrothermal mixing

• Electrothermal force:

interaction of gradients in conductivity and permittivity (produced by Joule Heating) with electric field

• Advantages: Easy integration

AC=>avoid electrolysis

Effective for high conductivity solutions

Motivation: Microfluidic manipulation


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Outline

• Standard numerical model for ACET

• Experimental discrepancy for high conductivity

• Solution: strong thermo-electric coupling using Comsol software

• Results

• Conclusion and Future works


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Standard numerical model for ETF

• Electric Field

• Temperature Field

• Electrothermal Body Force

• Fluid velocity Field


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=> Temperature: ΔT ~ V2

Estimation of velocity amplitude voltage dependence

=> u ~ ΔT E2

u ~ V4

=> Velocity: u ~


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Experimental Setup:


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Comsol Implementation


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Comsol Implementation


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=> Temperature: ΔT ~ V2

Estimation of velocity amplitude voltage dependence

=> u ~ ΔT E2

u ~ V4

=> Velocity: u ~


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Experimental discrepancy


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Strong Thermo-Electric Coupling


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Results:


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Results:


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Conclusion

Strong thermo-electric coupling and

Temperature dependent expression of parameters

are necessary to correctly model ACET at high gradient of temperature.

Future Works• Include buoyancy to the model.• Check for which parameters buoyancy is NOT

negligeable.

S.Loire: Study of AC electrothermal Fluid Flow Models

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