The influence of surface tension and equilibrium contact angle on the spreading and receding of water droplets impacting a solid surface

2012 ◽  
Author(s):  
Philip A. Lin ◽  
Alfonso Ortega
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Solid Surface ◽  
Equilibrium Contact Angle ◽  
Water Droplets

Investigation of Pool Boiling Critical Heat Flux Enhancement on a Modified Surface Through the Dynamic Wetting of Water Droplets

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Ho Seon Ahn ◽  
Joonwon Kim ◽  
Moo Hwan Kim
Keyword(s):  
Surface Tension ◽  
Heat Flux ◽  
Contact Angle ◽  
Critical Heat Flux ◽  
Pool Boiling ◽  
Water Layer ◽  
Contact Angles ◽  
Water Droplets ◽  
Dynamic Wetting ◽  
Modified Surface

Dynamic wetting behaviors of water droplet on the modified surface were investigated experimentally. Dynamic contact angles were measured as a characterization method to explain the extraordinary pool boiling critical heat flux (CHF) enhancement on the zirconium surface by anodic oxidation modification. The sample surface is rectangular zirconium alloy plates (20 × 25 × 0.7 mm), and 12 μl of deionized water droplets were fallen from 40 mm of height over the surface. Dynamic wetting movement of water on the surface showed different characteristics depending on static contact angle (49.3 deg–0 deg) and surface temperature (120 °C–280 °C). Compared with bare surface, wettable and spreading surface had no-receding contact angle jump and seemed stable evaporating meniscus of liquid droplet in dynamic wetting condition on hot surface. This phenomenon could be explained by the interaction between the evaporation recoil and the surface tension forces. The surface tension force increased by micro/nanostructure of the modified zirconium surface suppresses the vapor recoil force by evaporation which makes the water layer unstable on the heated surface. Thus, such increased surface force could sustain the water layer stable in pool boiling CHF condition so that the extraordinary CHF enhancement could be possible.

Some remarks on the solid surface tension determination from contact angle measurements

2017 ◽  
Vol 405 ◽  
pp. 88-101 ◽  
Author(s):  
Anna Zdziennicka ◽  
Katarzyna Szymczyk ◽  
Joanna Krawczyk ◽  
Bronisław Jańczuk
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Solid Surface ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Solid Surface Tension

The Effect of Drop Volume on Contact Angle

1991 ◽  
Vol 54 (3) ◽  
pp. 232-235 ◽  
Author(s):  
JOSEPH MCGUIRE ◽  
JIANGUO YANG
Keyword(s):  
Contact Angle ◽  
Surface Properties ◽  
Solid Surface ◽  
Contact Surface ◽  
Contact Angles ◽  
Equilibrium Contact Angle ◽  
Drop Volume ◽  
Food Contact ◽  
Food Contact Surface ◽  
Limiting Value

The effect of drop volume on the equilibrium contact angle, used in evaluation of food contact surface properties, was measured for liquids exhibiting both polar and nonpolar character on six different materials. Drop volumes used ranged from 2 to 40 μl. Contact angles were observed to increase with increasing drop volume in a range below some limiting value, identified as the critical drop volume (CDV). The CDV varied among materials and is explained with reference to surface energetic heterogeneities exhibited by each type of solid surface.

Investigation of Bubble Nucleation on Platinum Solid Surface Using Molecular Dynamics (MD) Simulation

2010 ◽  
Author(s):  
S. M. Mirnouri Langroudi ◽  
M. Ghasemi ◽  
A. Shahabi ◽  
H. Rezaei Nejad
Keyword(s):  
Molecular Dynamics ◽  
Surface Tension ◽  
Contact Angle ◽  
Solid Surface ◽  
Bubble Radius ◽  
Pair Potential ◽  
Computer Code ◽  
Bubble Nucleation ◽  
Solid Surfaces ◽  
Density Profiles

The main purpose of this paper is to numerically investigate the contact angle of a bubble on a solid surface and the effect of bubble curvature on the surface tension. A computer code based on Molecular Dynamics method is developed. The code carries out a series of simulations to generate bubbles between two planar solid surfaces for different wettabilities. In our simulation, the surface wettability affects the bubble contact angle and curvature. The pair potential for the liquid–liquid and liquid-solid interaction is considered using Lennard-Jones model. Density profiles are locally calculated. Furthermore, surface tension is computed using Young-Laplace equation. It is observed that the gas pressure is independent of the bubble radius. However, the liquid pressure becomes more negative as the radius decreases. In addition, the amount of surface tension decreases by decrease of the radius.

Evaporation of Water Droplets Placed on a Heated Horizontal Surface

2002 ◽  
Vol 124 (5) ◽  
pp. 854-863 ◽  
Author(s):  
Orlando E. Ruiz ◽  
William Z. Black
Keyword(s):  
Contact Angle ◽  
Heat Conduction ◽  
Solid Surface ◽  
Fluid Motion ◽  
Surface Shape ◽  
Evaporation Process ◽  
Water Droplets ◽  
Conduction Model ◽  
Heat Conduction Model ◽  
Internal Fluid

A numerical analysis of the evaporation process of small water droplets with diameters of 1 mm or less that are gently deposited on a hot isothermal solid surface has been performed. This study considers the internal fluid motion that occurs as a result of the thermocapillary convection in the droplet and it determines the effect of fluid motion on the heat transfer between the drop and the solid surface. This study is particularly relevant because the internal fluid motion has not been considered in previous numerical and analytical models presented in the literature. To assess the effects of internal fluid motion, the model results are compared to numerical results provided by a heat conduction model that neglects the fluid motion. The Navier-Stokes and Thermal Energy equations are solved using the Artificial Compressibility Method with Dual Time Stepping. Boundary-fitted grids are used to track the changes in the droplet surface shape during the evaporation process. The numerical simulations have demonstrated that the internal fluid motion provides vastly different temperature distributions in the drop compared to the results from the heat conduction model that neglects fluid motion. The evolution of the droplet geometry was simulated from an initial spherical-shaped cap until the contact angle was close to the receding contact angle.

scholarly journals Characterizing surface wetting and interfacial properties using enhanced sampling (SWIPES)

Soft Matter ◽  
2019 ◽  
Vol 15 (5) ◽  
pp. 860-869 ◽  
Author(s):  
Hao Jiang ◽  
Suruchi Fialoke ◽  
Zachariah Vicars ◽  
Amish J. Patel
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Solid Surface ◽  
Efficient Method ◽  
Liquid Surface ◽  
Liquid Droplet ◽  
Interfacial Properties ◽  
Enhanced Sampling ◽  
Surface Wetting ◽  
Liquid Surface Tension

We introduce an accurate and efficient method for characterizing surface wetting and interfacial properties, such as the contact angle made by a liquid droplet on a solid surface, and the vapor–liquid surface tension of a fluid.

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