Microfluidic Rheometry and Particle Settling: Characterizing the Effect of Polymer Solution Elasticity

Area of Science:

• Rheology and Fluid Dynamics
• Polymer Science
• Particle Transport

Background:

• Efficient particle transport in polymeric fluids is crucial for industrial processes.
• The role of fluid elasticity in particle carrying capacity remains underexplored.
• Viscoelastic fluids offer potential for enhanced particle transport.

Purpose of the Study:

• To experimentally investigate the influence of fluid elasticity on particle drag coefficient.
• To establish a proxy for measuring the particle-carrying capacity of viscoelastic fluids.
• To provide a unique dataset for moderate Weissenberg numbers (0

Main Methods:

• Utilized two elastic fluid formulations with distinct relaxation times and constant shear viscosity.
• Employed microfluidic rheometry for accurate relaxation time determination (milliseconds).
• Used a calibrated experimental setup with advanced particle velocity measurement techniques and varied sphere characteristics.

Main Results:

• Observed a subtle reduction in drag coefficient at low elasticity (Wi<1).
• Demonstrated a considerable enhancement in drag coefficient at high elasticity (Wi>1).
• Experimental data showed strong agreement with direct numerical simulations (R²=0.982).

Conclusions:

• Fluid elasticity significantly impacts particle drag and carrying capacity.
• The findings support the use of numerical simulations for comparing fluid performance.
• This research provides a foundation for designing optimized polymeric fluids for particle transport.