Experimental Investigation of Water Droplet Impact on the Electrospun Superhydrophobic Cylindrical Glass: Contact Time, Maximum Spreading Factor, and Splash Threshold

Langmuir ◽  
2020 ◽  
Vol 36 (45) ◽  
pp. 13498-13508
Author(s):  
Sedigheh Khanzadeh Borjak ◽  
Roohollah Rafee ◽  
Mohammad Sadegh Valipour
Keyword(s):  
Experimental Investigation ◽  
Water Droplet ◽  
Contact Time ◽  
Droplet Impact ◽  
Spreading Factor ◽  
Cylindrical Glass ◽  
Maximum Spreading

Dynamic of Water Droplet Impacting on a Hydrophilic Surface Accompanied With Stagnation Flow

2014 ◽  
Author(s):  
Morteza Mohammadi ◽  
Mohammadreza Attarzadeh ◽  
Moussa Tembely ◽  
Ali Dolatabadi
Keyword(s):  
Shear Flow ◽  
Water Droplet ◽  
High Speed ◽  
Air Flow ◽  
Droplet Impact ◽  
Impact Behavior ◽  
Aluminum Surface ◽  
High Speed Photography ◽  
Stagnation Flow ◽  
Maximum Spreading

Droplet impact on solid surfaces has been extensively reported in the literature, however the effect of accompanying air flow on the outcome of impacting droplet has yet to be addressed and analyzed which is similar to real scenario of impacting water droplet on aircraft’s leading edge at in-flight icing conditions. This study addresses the net effect of airflow (i.e. stagnation and the resultant shear flow) on the impacting water droplet with the same droplet impact velocity which is exposed to different airspeeds. In order to provide stagnation flow, a droplet accelerator was built which can generate different airspeeds up to 20 m/s. Droplet impact behavior accompanied with stagnation flow on a polished aluminum surface with a contact angle of 70° was investigated by high speed photography. 2.5 mm water droplet size with impact velocities of 2, 2.5 and 3 m/s which correspond to non-splashing regime of impacts are exposed to three different regimes of air speeds namely 0 (i.e. still air case), 10, and 20 m/s. It was observed that when droplet reaches to its maximum spreading diameter, some fingered shape at the end of spreading lamella (i.e. Rayleigh-Taylor instability) is appeared. When stagnation flow is present these fingered shape droplets are exposed to the generated shear flow close to the substrate (i.e. Homann flow approach) causes a droplet break up while complete non-splashing regime is observed in still air case. In spite of the fact that maximum spreading diameter is not largely affected by air flow compare to still air case, droplet height variation is significantly reduced by about 70 percent for strong stagnation flow (i.e. 20 m/s) which generates non-recoiling condition resulting in the thin film formation.

scholarly journals Study of the effect of surface wettability on droplet impact on spherical surfaces

2020 ◽  
Vol 15 (3) ◽  
pp. 414-420 ◽  
Author(s):  
Xiaohua Liu ◽  
Kaimin Wang ◽  
Yaqin Fang ◽  
R J Goldstein ◽  
Shengqiang Shen
Keyword(s):  
Contact Angle ◽  
Impact Velocity ◽  
Droplet Impact ◽  
Surface Wettability ◽  
Spreading Factor ◽  
Curvature Ratio ◽  
Spherical Surfaces ◽  
The Impact ◽  
Maximum Spreading ◽  
Effect Of Surface

Abstract The effect of surface wettability on droplet impact on spherical surfaces is studied with the CLSVOF method. When the impact velocity is constant, with the increase in the contact angle (CA), the maximum spreading factor and time needed to reach the maximum spreading factor (tmax) both decrease; the liquid film is more prone to breakup and rebound. When CA is constant, with the impact velocity increasing, the maximum spreading factor increases while tmax decreases. With the curvature ratio increasing, the maximum spreading factor increases when CA is between 30 and 150°, while it decreases when CA ranges from 0 to 30°.

Honeycomb porous films of pentablock copolymer on liquid substrates via breath figure method and their hydrophobic properties with static and dynamic behaviour

RSC Advances ◽  
2015 ◽  
Vol 5 (27) ◽  
pp. 21084-21089 ◽  
Author(s):  
Zhiguang Li ◽  
Xiaoyan Ma ◽  
Duyang Zang ◽  
Qing Hong ◽  
Xinghua Guan
Keyword(s):  
Water Droplet ◽  
Dynamic Behaviour ◽  
Droplet Impact ◽  
Impact Behavior ◽  
Porous Films ◽  
Hydrophobic Properties ◽  
Breath Figure ◽  
Breath Figure Method ◽  
Pentablock Copolymer ◽  
Maximum Spreading

The peeled film obtained on the isopropanol substrate through breath figure method exhibits the best hydrophobic properties, and the water droplet impact behavior shows an obvious rebound tendency and a weak maximum spreading diameter.

EXPERIMENTAL INVESTIGATION OF A SINGLE DROPLET IMPACT ONTO A SESSILE DROP

2010 ◽  
Vol 20 (10) ◽  
pp. 909-922 ◽  
Author(s):  
Nikos Nikolopoulos ◽  
George Strotos ◽  
Konstantinos-Stephen P. Nikas ◽  
Manolis Gavaises ◽  
Andreas Theodorakakos ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Sessile Drop ◽  
Droplet Impact ◽  
Single Droplet
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