Pressure-driven transport of particles through a converging-diverging microchannel

Area of Science:

• Fluid dynamics
• Microfluidics
• Particle transport

Background:

• Understanding particle behavior in microfluidic devices is crucial for applications in diagnostics and synthesis.
• Microchannels offer controlled environments for studying fluid-particle interactions.

Purpose of the Study:

• To investigate pressure-driven particle transport through a symmetric converging-diverging microchannel.
• To analyze the influence of various parameters on particle translation and rotation.
• To assess the potential of these microchannels for particle separation and ordering.

Main Methods:

• Solving coupled nonlinear Navier-Stokes and continuity equations.
• Utilizing the arbitrary Lagrangian-Eulerian finite-element technique.
• Simulating particle behavior under varying pressure gradients, particle sizes, and channel geometries.

Main Results:

• Particle translation generally accelerates in converging sections and decelerates in diverging sections, peaking at the throat.
• Particles with diameters near the throat width exhibit a three-stage transport: acceleration, deceleration, and reacceleration.
• Particle rotation increases with proximity to the channel wall; no rotation occurs on the centerline.
• Pressure gradient does not affect the velocity ratio between the microchannel and a straight channel.

Conclusions:

• Converging-diverging microchannels are effective for passive separation and ordering of biological and synthetic particles.
• Particle transport dynamics are significantly influenced by particle size relative to channel geometry.
• The study provides insights into microfluidic particle manipulation for advanced applications.