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Fabricating High-viscosity Droplets using Microfluidic Capillary Device with Phase-inversion Co-flow Structure
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Motion of Droplets in Lyophilic Axially Varying Geometry-Gradient Tubes
Zhiqiang Xiao1, Xiaoling Hu1,2, Di Wu3
1School of Mechanical Engineering and Mechanics, Xiangtan University, Xiangtan 411105, China.
Langmuir : the ACS Journal of Surfaces and Colloids
|May 26, 2023
Summary
Droplet motion in axially varying geometry-gradient tubes (AVGGTs) was studied. Surface tension forces and internal negative pressure drive droplet self-transport from large to small openings, while dimensional analysis predicts stopping locations for reverse motion.
Area of Science:
- Fluid Dynamics
- Surface Science
- Materials Science
Background:
- Droplet transport is a common natural phenomenon with diverse technological applications.
- Understanding droplet dynamics in confined geometries is crucial for microfluidics and material processing.
Purpose of the Study:
- To investigate droplet motion in a lyophilic axially varying geometry-gradient tube (AVGGT).
- To analyze droplet self-transport and stuck behaviors in both forward (L to S) and reverse (S to L) directions.
- To develop theoretical models and experimental correlations for droplet dynamics in AVGGTs.
Main Methods:
- Theoretical analysis using simplified Navier-Stokes equations.
- Experimental investigation of droplet motion under varying parameters.
- Dimensional analysis to predict droplet stopping locations.
Main Results:
- Surface tension forces can act as driving or impeding forces based on droplet geometry and AVGGT.
- Negative pressure-induced bridge liquid force drives self-transport from large to small openings (L to S).
- Correlations were established for droplet stopping locations during S to L motion.
Conclusions:
- The study elucidates the mechanisms governing droplet motion in AVGGTs, highlighting the role of surface tension and internal pressure.
- Theoretical and experimental findings provide a framework for controlling droplet transport in gradient geometries.
- The research offers insights for designing devices utilizing controlled droplet movement.
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