Size-Dependent Acoustophoresis in Rectangular Microchannels: Critical Particle Radius and Multidimensional Field...

Area of Science:

• Microsystems Engineering
• Soft Matter Physics
• Biomedical Diagnostics

Background:

• Acoustophoresis is key for particle manipulation in microfluidic devices.
• Precise control of particle size thresholds is crucial for acoustofluidic tweezers.
• Understanding the transition between radiation-force trapping and streaming transport is essential.

Purpose of the Study:

• To establish quantitative correlations between critical particle radius thresholds and geometric parameters in coupled standing-wave fields.
• To investigate particle transport regimes in acoustofluidic systems.
• To provide engineering guidelines for optimizing acoustic tweezers.

Main Methods:

• Systematic numerical investigations using finite element modeling in rectangular microchannels with 2D confinement.
• Analytical validation through boundary-layer force equilibrium analysis.
• Parametric studies of channel size and wavelength ratios.

Main Results:

• Geometric confinement leads to characteristic scaling laws for critical radius in 1D standing waves.
• 1D models show predictive accuracy for specific wavelength ratios but fail in coupled-mode fields.
• Orthogonal wave superposition in 2D configurations reduces critical radius by suppressing streaming velocities.

Conclusions:

• The study provides fundamental understanding of size-selective acoustophoresis.
• Quantitative correlations reveal how geometric parameters influence critical particle size thresholds.
• Findings offer engineering guidelines for enhanced performance in acoustic tweezers design.