scholarly journals Droplet impact behavior on heated micro-patterned surfaces

2016 ◽  
Vol 119 (11) ◽  
pp. 114901 ◽  
Author(s):  
Wenbin Zhang ◽  
Tongxu Yu ◽  
Jing Fan ◽  
Weijie Sun ◽  
Zexian Cao
Keyword(s):  
Droplet Impact ◽  
Impact Behavior ◽  
Patterned Surfaces

SUMMARY OF STUDIES OF COREXIT DISPERSANT DROPLET IMPACT BEHAVIOR INTO OIL SLICKS AND DISPERSANT DROPLET EVAPORATION1,2

2008 ◽  
Vol 2008 (1) ◽  
pp. 797-800 ◽  
Author(s):  
Timothy A. Ebert ◽  
Roger Downer ◽  
James Clark ◽  
Charles A. Huber
Keyword(s):  
High Speed ◽  
Impact Analysis ◽  
Droplet Impact ◽  
Impact Behavior ◽  
Oil Slick ◽  
Corexit 9500 ◽  
Droplet Sizes ◽  
Evaporative Loss ◽  
Pass Through ◽  
Oil Films

ABSTRACT This paper presents the results of two related studies concerning the aerial application of dispersants. The first study characterized the interactions of various sized Corexit 9500 and 9527 dispersant droplets with oil films of from 0.1 mm to 3.0 mm thickness. A film thickness of 0.1 mm was selected as the end point since this is the thinnest oil film recommended for the application of dispersants. The results of the high speed video droplet impact analysis showed that droplet diameters of 1,000 microns will not pass through an oil slick of 0.1 mm and mix with the underlying water column and that slick thickness of 0.2 mm or more will prevent even 2,000 micron diameter droplets from passing through the slick. These droplet sizes are considerably larger than the current ASTM Standard recommended droplet size of 300–500 microns for dispersant application. Additionally, it was shown that droplets that do pass through an oil slick will in whole or in part rise back up to the oil water interface. The second study characterized and compared the evaporation rates of Corexit 9500 and 9527 droplets with water over a 20 minute period under varying conditions of humidity and temperature. Under high evaporative conditions of high temperature (90° F) and low humidity (40%), droplets ranging from 0.25 to 1 uL showed 2–10% evaporative loss for Corexit 9500, 28–35% evaporative loss for Corexit 9527, and complete evaporative loss for water. When tested at low evaporative conditions of low temperature (40° F) and high humidity (95%), no evaporative loss was recorded for droplets of either 9500 or 9527, and water lost 18%.

scholarly journals Numerical simulation of droplet impact on wettability-patterned surfaces

2020 ◽  
Vol 5 (7) ◽  
Author(s):  
Antonio Russo ◽  
Matteo Icardi ◽  
Mohamed Elsharkawy ◽  
Diego Ceglia ◽  
Pietro Asinari ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Droplet Impact ◽  
Patterned Surfaces

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 Numerical Simulation of Droplet Impact on Patterned Surfaces

2007 ◽  
Vol 16 (5-6) ◽  
pp. 713-721 ◽  
Author(s):  
H.B. Parizi ◽  
L. Rosenzweig ◽  
J. Mostaghimi ◽  
S. Chandra ◽  
T. Coyle ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Droplet Impact ◽  
Patterned Surfaces

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.

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