Investigating the fluid dynamics of rapid processes within microfluidic devices using bright-field microscopy.

Area of Science:

• Fluid dynamics
• Microfluidics
• Biotechnology

Background:

• Microfluidic devices are crucial in biological and chemical sciences, often featuring complex designs that cause unusual fluid dynamics.
• Understanding these fluid dynamics is essential for developing advanced analytical tools.

Purpose of the Study:

• To present an accurate method for studying rapid fluid dynamics in microfluidic systems.
• To enable velocimetry analysis of high-speed phenomena not feasible with current micron-resolution particle image velocimetry (μPIV) methods.

Main Methods:

• Utilized bright-field microscopy with white light illumination and a high-speed camera.
• Combined Ghost Particle Velocimetry with moving object detection for submicron particle tracking via speckle pattern cross-correlation.
• Applied the technique to analyze flow fields over a micro-pillar and droplet generation in a flow focusing geometry.

Main Results:

• Successfully measured flow fields at high volumetric flow rates over a micro-pillar, showing excellent agreement with computational fluid dynamics simulations.
• Investigated the dynamics of droplet generation in a flow focusing microfluidic device.
• Demonstrated the capability for high-speed phenomena velocimetry analysis.

Conclusions:

• The presented technique offers an accurate and effective approach for studying microfluidic fluid dynamics, particularly for rapid processes.
• This method expands the capabilities beyond traditional μPIV, enabling new research avenues in microfluidic applications.