Experimental investigations on geometry modulated solute mixing in viscoelastic media

TL;DR

This paper investigates how geometrically modified microchannels influence solute mixing in viscoelastic fluids, revealing inertio-elastic instability as a key factor enhancing mixing efficiency in microfluidic devices.

Contribution

It introduces a novel analysis combining experimental and numerical methods to understand inertio-elastic instability effects in geometrically modified microchannels for viscoelastic fluids.

Findings

Inertio-elastic instability occurs in modified microchannels.

Mixing efficiency is significantly improved by channel geometry.

The study offers insights for designing passive micromixers.

Abstract

In this study, geometrically modified microchannels fabricated using stereolithography technique are employed to analyze micromixing of polymeric solutions. Experimental and numerical analyses were conducted to evaluate the qualitative and quantitative validity of the Newtonian fluid flow inside the geometrically modified channels. An in-house image processing code developed in MATLAB was used to analyze the dye concentration distributions resulting from complex fluid transport and mixing within the modified channels. Our analysis illustrates the existence of inertio-elastic instability in the geometrically modified microchannels for the transport of viscoelastic fluids. In addition, the presence of inertio-elastic instability significantly enhances mixing efficiency as a result of the interaction between viscoelasticity and modified channel geometry. This analysis provides important physical insights into the cost-effective design and operation of microfluidic devices that handle viscoelastic fluids and could be useful in designing and analyzing a passive micromixers that transport bio/polymeric fluids inside microchannels.