Numerical study of droplet motion on discontinuous wetting gradient surface with rough strip

2021 ◽  
Vol 33 (1) ◽  
pp. 012111
Author(s):  
Wenbin Li ◽  
Jiacai Lu ◽  
Grétar Tryggvason ◽  
Ying Zhang
Keyword(s):  
Numerical Study ◽  
Droplet Motion ◽  
Gradient Surface

Numerical study of droplet breakup in an asymmetric T-junction microchannel with different cross-section ratios

2021 ◽  
pp. 2250023
Author(s):  
Milad Isanejad ◽  
Keivan Fallah
Keyword(s):  
Cross Section ◽  
Numerical Study ◽  
Three Dimensional ◽  
Droplet Breakup ◽  
Width Ratio ◽  
Two Phase ◽  
Droplet Motion ◽  
Daughter Droplets ◽  
Breakup Time ◽  
Good Agreement

In this study, numerical simulations are conducted to investigate droplet breakup in an asymmetric [Formula: see text]-junction microchannel with different cross-section ratios. To this approach, a two-phase model based on the volume of fluid (VOF) method is adopted to study the three-dimensional feature of droplet motion inside [Formula: see text]-junctions. The comparison reveals that the present results are in good agreement with previous studies. The effects of the capillary number (Ca), the non-dimensional droplet length ([Formula: see text]), and the non-dimensional width ratio ([Formula: see text]) on the breakup time and splitting ratio of daughter droplets are studied. Five distinct regimes are observed involving the non-breakup, breakup with tunnel, breakup without tunnel, asymmetric breakup, and sorting. Achieved results indicate that the time of breakup ([Formula: see text]) increases about 15% when the Ca is increased from 0.0134 to 0.0268 (about 100%). It is also found that the mass center of the mother droplet in the primary channel is shifted to a larger wide branch, which facilitates the asymmetric breakup of the droplet in a [Formula: see text]-junction microchannel.

Numerical Study of Droplet Motion in a Hydrophilic/Hydrophobic Microchannel

2008 ◽  
Author(s):  
Jiyoung Choi ◽  
Gihun Son
Keyword(s):  
Proton Exchange Membrane ◽  
Numerical Study ◽  
Side Wall ◽  
Contact Angles ◽  
Proton Exchange ◽  
Droplet Motion ◽  
Droplet Dynamics ◽  
Droplet Shape ◽  
Hydrophobic Microchannel ◽  
Exchange Membrane

The droplet dynamics in a hydrophilic/hydrophobic microchannel, which is applicable to a typical proton exchange membrane fuel cell (PEMFC), is studied numerically by solving the equations governing the conservation of mass and momentum. The liquid-gas interface or droplet shape is determined by a level set method which is modified to treat the contact angles. The matching conditions at the interface are accurately imposed by incorporating the ghost fluid approach based on a sharp-interface representation. Based on the numerical results, the droplet dynamics including the sliding and detachment of droplets is found to depend significantly on the contact angle. The effects of inlet flow velocity, droplet size and side wall on the droplet motion are quantified. Also, a droplet removal process is demonstrated on the combination of hydrophilic and hydrophobic surfaces.

Mechanical-activated digital microfluidics with gradient surface wettability

Lab on a Chip ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 223-232 ◽  
Author(s):  
Lin Qi ◽  
Ye Niu ◽  
Cody Ruck ◽  
Yi Zhao
Keyword(s):  
Digital Microfluidics ◽  
Hydrophobic Surface ◽  
Surface Wettability ◽  
Long Distance ◽  
Droplet Motion ◽  
Surface Patterns ◽  
Droplet Manipulation ◽  
Gradient Surface

Long-distance droplet motion and selective droplet manipulation on repeated hydrophobic surface patterns with gradient wettability by in-plane cyclic vibration.

Droplet Motion on a Shape Gradient Surface

Langmuir ◽  
2017 ◽  
Vol 33 (17) ◽  
pp. 4172-4177 ◽  
Author(s):  
Yanfen Zheng ◽  
Jiang Cheng ◽  
Cailong Zhou ◽  
Haiting Xing ◽  
Xiufang Wen ◽  
...  
Keyword(s):  
Droplet Motion ◽  
Shape Gradient ◽  
Gradient Surface

Numerical study of the low-frequency atomic dynamics in a Lennard-Jones glass

1998 ◽  
Vol 77 (2) ◽  
pp. 473-484 ◽  
Author(s):  
M. Sampoli, P. Benassi, R. Dell'Anna,
Keyword(s):  
Numerical Study ◽  
Low Frequency ◽  
Lennard Jones
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