Quantitative study for control of air-liquid segmented flow in a 3D-printed chip using a vacuum-driven system

Area of Science:

• Microfluidics
• Fluid dynamics
• Chemical engineering

Background:

• Microfluidic systems enable device miniaturization and reduced sample volumes.
• Two-phase segmented flow is crucial for micro-mixing, chemical reactions, and heat/mass transfer.
• Controlling droplet or bubble formation is essential in microfluidics.

Purpose of the Study:

• To develop a simple, portable microfluidic system for generating and controlling segmented flow.
• To analyze the relationship between hydraulic resistance, pressure drop, and segmented flow characteristics.
• To investigate the impact of segmentation on mixing efficiency.

Main Methods:

• A 3D-printed microfluidic chip integrated with a single vacuum pump was used.
• Image processing techniques analyzed liquid slug size and flow rate.
• Mixing efficiency was quantified by measuring color intensity changes of inks.

Main Results:

• Liquid slug size and flow rate showed a near-linear relationship with hydraulic resistance.
• Variations in pump flow rate resulted in a non-linear trend for liquid slug size.
• The microfluidic system produced liquid slugs ranging from 0.1 to 2 µL.
• Segmentation significantly improved mixing efficiency, indicated by a higher homogeneity factor.

Conclusions:

• The study provides insights into liquid slug/droplet formation and segmented flow prediction.
• Hydraulic resistance and pressure drop are key parameters for controlling segmented flow in microfluidics.
• The developed system offers a simple and portable solution for microfluidic applications.