Periodic microfluidic bubbling oscillator: insight into the stability of two-phase microflows

Area of Science:

• Fluid Dynamics
• Microfluidics
• Foam Science

Background:

• Foam flow in microfluidic devices exhibits complex behaviors.
• Controlling bubble size and flow rate is crucial for microfluidic applications.

Purpose of the Study:

• To investigate the periodically oscillating foam flow in a microfluidic device.
• To elucidate the relationship between foam topology and flow rate.
• To develop a model for predicting and controlling bubble formation.

Main Methods:

• Experimental observation of foam flow in a microfluidic device.
• Analysis of bubble volume and flow rate variations.
• Development of a retroaction model based on downstream bubble presence.

Main Results:

• Observed periodic oscillations in foam flow with constant input parameters.
• Demonstrated a two-fold variation in bubble volume and flow rate.
• Established a direct link between foam topology alternations and flow rate changes.
• Validated a retroaction model where downstream bubbles influence new bubble formation.

Conclusions:

• The study provides a model for understanding and controlling foam flow dynamics in microfluidics.
• Insights gained are valuable for achieving both monodispersity and controlled polydispersity in bubble generation.
• The retroaction model offers a method for precise control over bubble size and flow characteristics.