Robust and high-resolution simulations of nonlinear electrokinetic processes in variable cross-section channels

Area of Science:

• Computational fluid dynamics
• Electrochemistry
• Chemical engineering

Background:

• Complex electrokinetic processes are crucial in microfluidic devices.
• Simulating these phenomena in channels with varying cross-sections presents significant computational challenges.
• Existing models often lack the accuracy or efficiency needed for complex geometries.

Purpose of the Study:

• To develop a quasi-1D model for simulating electrokinetic transport in channels with nonuniform cross-sectional areas.
• To create a stable and accurate numerical scheme for solving the governing equations.
• To demonstrate the model's capability in predicting enhanced detection sensitivity for techniques like Ion-Transport Phenomena (ITP).

Main Methods:

• Developed a quasi-1D model using local cross-sectional area averaging and lubrication theory.
• Incorporated chemical equilibrium, Taylor-Aris dispersion, and ionic strength effects.
• Implemented a dissipative finite volume scheme coupled with adaptive grid refinement for stability and accuracy.

Main Results:

• The numerical scheme provides fast, stable, and high-resolution solutions.
• Achieved accurate simulations using significantly fewer grid points compared to existing methods.
• Demonstrated increased detection sensitivity for ITP in converging channels.

Conclusions:

• The proposed model and numerical scheme offer an efficient and accurate approach for simulating complex electrokinetic flows in variable cross-section channels.
• The method shows excellent agreement with experimental data for ITP simulations.
• This work has implications for optimizing microfluidic device design and analytical techniques.