Numerical Study of Particle-Fluid Flow Under AC Electrokinetics in Electrode-Multilayered Microfluidic Device

Area of Science:

• Fluid Dynamics
• Electrokinetics
• Microfluidics

Background:

• Particle-fluid dynamics in complex electric fields are crucial for microfluidic applications.
• Understanding alternating current electrokinetics (ACEK) phenomena is key to controlling particle behavior.

Purpose of the Study:

• To numerically investigate three-dimensional particle motion in a high conductivity medium under ACEK.
• To elucidate the combined effects of ac electrothermal (ACET), thermal buoyancy (TB), and dielectrophoresis (DEP) on particle-fluid flow.
• To validate the simulation model with experimental data.

Main Methods:

• Numerical simulation using the Eulerian-Lagrangian method with finite volume discretization.
• Coupling of thermal-fluid-electrical and dispersed particle models.
• Experimental validation using particle tracking velocimetry on cell suspensions.

Main Results:

• ACET generates short-range vortices, while TB creates long-range circulation in the microfluidic device.
• Positive dielectrophoresis (DEP) was observed to decelerate cells near electrodes.
• The 3-D DEP-effective, ACET-dominant, and TB-dominant regions were predicted.

Conclusions:

• The study clarifies the flow mechanisms and dominant regions of ACEK phenomena in the microfluidic device.
• The validated 3-D simulation provides insights into particle manipulation using combined electrokinetic effects.
• This research contributes to the understanding and design of microfluidic systems for particle manipulation.