Optical Feedback Interferometry for Velocity Measurement of Parallel Liquid-Liquid Flows in a Microchannel

Area of Science:

• Microfluidics
• Fluid dynamics
• Optical sensing technologies

Background:

• Optical feedback interferometry (OFI) is a compact sensing technique.
• OFI has been recently implemented for flow measurements in microchannels.
• Multiphase flow analysis at the microscale presents unique challenges.

Purpose of the Study:

• To implement OFI for the microscale analysis of multiphase flows.
• To investigate parallel flows of two immiscible fluids using OFI.
• To establish OFI as a novel sensing technique for multiphase systems.

Main Methods:

• Implementation of OFI for multiphase flow analysis.
• Measurement of velocity profiles in individual fluid phases.
• Estimation of the interface location between immiscible fluids.
• Comparison of experimental results with a Couette viscous flow model.

Main Results:

• Successful application of OFI to multiphase microflows.
• Accurate measurement of velocity profiles for each phase.
• Reliable estimation of the interface location.
• Good agreement between experimental data and theoretical Couette flow profiles.

Conclusions:

• OFI is demonstrated as a pioneering sensing technique for microscale multiphase flows.
• The study provides a validated method for analyzing immiscible fluid interactions.
• This approach offers a new tool for studying complex multiphase phenomena, including droplet flows.