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Dynamics of high viscosity contrast confluent microfluidic flows
Michael E Kurdzinski1, Berrak Gol1, Aaron Co Hee1
1School of Engineering, RMIT University, Melbourne, Victoria, Australia.
Scientific Reports
|July 21, 2017
Summary
High viscosity contrast in microfluidic flows creates tapered core structures. Flow rates influence these structures, leading to instabilities and distinct dynamic regimes like broken or oscillating cores.
Area of Science:
- Fluid dynamics
- Microfluidics
- Rheology
Background:
- Microfluidic flows typically exhibit laminar behavior, with stable interfaces between confluent fluids.
- High viscosity contrasts can disrupt laminar flow, causing interface instabilities.
Purpose of the Study:
- To investigate the dynamics of high viscosity contrast confluent flows in microfluidics.
- To characterize the formation and behavior of tapered core structures under varying flow conditions.
Main Methods:
- Experimental study using a microfluidic flow focusing system.
- Confinement of a highly viscous glycerol core flow by water sheath flows.
- Analysis of tapered core structure dynamics and interface instability patterns.
Main Results:
- Formation of tapered core structures with increasing sheath flow rate.
- Induction of local instability patterns at the core-sheath interface.
- Identification of stable, disturbed, broken, and oscillating core regimes based on instability and core length.
Conclusions:
- The dynamics of tapered core structures are governed by interface instability and core length.
- Novel analysis of core displacement amplitude and frequency in broken and oscillating regimes.
- Understanding these instabilities is crucial for controlling microfluidic processes with high viscosity contrast fluids.
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