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The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
Stream spreading in multilayer microfluidic flows of suspensions
Mona Utne Larsen1, Nina C Shapley
1Department of Chemical Engineering, Columbia University, 500 W. 120th Street, MC 4721, New York, New York 10027, USA.
Analytical Chemistry
|January 30, 2007
Summary
This study quantifies fluid stream spreading in microfluidics. Viscosity contrast significantly impacts stream width, with particle suspensions showing unique behavior at high concentrations due to shear-induced migration.
Area of Science:
- Fluid Dynamics
- Microfluidics
- Rheology
Background:
- Multilayer microfluidic flows involve complex fluid interactions.
- Understanding stream spreading is crucial for optimizing microfluidic device performance.
- Viscosity contrast between adjacent fluid streams influences flow behavior.
Purpose of the Study:
- To experimentally quantify the spreading of parallel streams in multilayer microfluidic flows.
- To investigate the effect of viscosity contrast on stream width.
- To analyze the behavior of Newtonian fluids and particle suspensions under varying viscosity ratios.
Main Methods:
- Utilizing a microfluidic device where three streams converge into a single channel.
- Employing fluorescence microscopy to track fluid interface locations.
- Testing Newtonian fluids and polymethylmethacrylate (PMMA) particle suspensions with varying viscosities and volume fractions.
Main Results:
- The steady-state width of the center stream strongly depends on the viscosity ratio, showing a near power-law relationship.
- Both Newtonian fluids and suspensions exhibited this dependence, but with differing slopes.
- High-concentration suspensions (phi = 0.30) deviated from Newtonian behavior, unlike low-concentration suspensions.
Conclusions:
- Viscosity ratio is a key parameter governing stream spreading in multilayer microfluidics.
- Shear-induced particle migration affects the rheological behavior of concentrated suspensions.
- Microfluidic experiments provide insights into complex fluid dynamics influenced by particle suspensions.
