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Inertio-elastic flow instabilities in a 90° bent microchannel.
Junghee Kim1, Sun Ok Hong, Tae Soup Shim
1Department of Energy Systems Research, Ajou University, Suwon 16499, Korea. jumin@ajou.ac.kr.
Soft Matter
|August 18, 2017
Summary
Flow instability in viscoelastic fluids, like poly(ethylene oxide) (PEO) solutions, was observed in bent microfluidic channels. This instability is influenced by polymer concentration, flow rate, and elasticity, impacting microfluidic device design.
Area of Science:
- Fluid Dynamics
- Microfluidics
- Polymer Science
Background:
- Microfluidic devices are crucial for testing biological samples with viscoelastic properties.
- Viscoelastic fluids, such as polymer solutions, are used for particle focusing in microchannels.
- Flow instability at low Reynolds numbers is a characteristic of viscoelastic fluids.
Purpose of the Study:
- To investigate flow instability in viscoelastic fluids within a 90° bent microfluidic channel.
- To determine the influence of polymer concentration, flow rate, and elasticity number on flow instability.
- To provide insights for designing microfluidic devices for applications like cell deformability measurement.
Main Methods:
- Utilized aqueous poly(ethylene oxide) (PEO) solutions to study viscoelastic flow.
- Systematically varied polymer concentration, flow rate, and elasticity number.
- Observed and analyzed flow instability in a 90° bent microfluidic geometry.
Main Results:
- Flow instability was detected in poly(ethylene oxide) solutions at concentrations as low as 50 ppm.
- Shear-thinning fluids exhibited stabilized flow.
- Flow instability was amplified when both elastic and inertial effects were significant.
Conclusions:
- Viscoelastic flow instability in bent microchannels is sensitive to low polymer concentrations.
- The interplay between elastic and inertial forces significantly affects flow stability.
- Findings are valuable for optimizing microfluidic device design for particle focusing and biological sample analysis.
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