Confined flow behaviour of droplets in microcapillary flow

Area of Science:

• Fluid dynamics
• Microfluidics
• Interfacial phenomena

Background:

• Droplet flow in confined geometries like microcapillaries is crucial for applications such as porous media flow.
• Theoretical models exist, but experimental data on droplet behavior under varying parameters remains limited.
• Key parameters influencing droplet motion include confinement, viscosity ratio, and capillary number.

Purpose of the Study:

• To experimentally investigate the flow behavior of axisymmetric confined droplets in microcapillaries.
• To analyze the influence of confinement, viscosity ratio, and capillary number on droplet velocity and deformation.
• To compare experimental findings with existing numerical solutions in the literature.

Main Methods:

• Utilized a water-in-soybean oil emulsion with a low viscosity ratio.
• Conducted experiments focusing on axisymmetric confined droplets in microcapillary flow.
• Systematically varied droplet size (confinement), viscosity ratio, and capillary number (Ca).

Main Results:

• Experimental data was obtained for droplet motion under varying confinement, viscosity ratio, and capillary number.
• The study quantified the effects of these three parameters on droplet velocity and deformation.
• A comparison was made between the experimental results and available numerical simulations.

Conclusions:

• The experimental campaign provides valuable data on microconfined droplet flow dynamics.
• Findings contribute to a better understanding of droplet behavior in microfluidic systems.
• The results serve as a benchmark for validating theoretical and numerical models.