scholarly journals Deposition of Water Droplets on the Solid Surface

1956 ◽  
Vol 2 (1) ◽  
pp. 49-50
Author(s):  
Tokio Uematu ◽  
Takesi Kano ◽  
Kazuhiro Takizawa ◽  
Masami Matuura
Keyword(s):  
Solid Surface ◽  
Water Droplets

Deformation of water droplets on solid surface in electric field

2006 ◽  
Vol 298 (2) ◽  
pp. 869-879 ◽  
Author(s):  
A. Moukengué Imano ◽  
A. Beroual
Keyword(s):  
Electric Field ◽  
Solid Surface ◽  
Water Droplets

scholarly journals Deposition of Water Droplets on the Solid Surface

1955 ◽  
Vol 8 (2) ◽  
pp. 122-127
Author(s):  
T. Uematsu ◽  
T. Kano ◽  
K. Takizawa ◽  
M. Matsuura
Keyword(s):  
Solid Surface ◽  
Water Droplets

scholarly journals Using the gravitational energy of water to generate power by separation of charge at interfaces

2015 ◽  
Vol 6 (6) ◽  
pp. 3347-3353 ◽  
Author(s):  
Yajuan Sun ◽  
Xu Huang ◽  
Siowling Soh
Keyword(s):  
Solid Surface ◽  
Gravitational Energy ◽  
Water Droplets

When water droplets (e.g., from rain) flow down a solid surface due to gravity, they can generate power.

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 Experimental Investigation on the Wind-driven Runback Motion of Water Droplets over Solid Surfaces with Different Wettabilities

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Liqun Ma ◽  
Zichen Zhang ◽  
Hui Hu
Keyword(s):  
Solid Surface ◽  
Contact Angles ◽  
Aircraft Icing ◽  
Water Droplets ◽  
Elastic Materials ◽  
Lotus Leaf ◽  
Liquid Lubricant ◽  
Measurement Results ◽  
Porous Surfaces ◽  
Ice Adhesion

Aircraft icing is widely recognized as one of the most serious weather hazards to flight safety. Specially designed hydro-/ice-phobic coatings are currently undergoing development for aircraft icing mitigation. It was found that hydro-/icephobic coatings would delay the ice accretion iover airframe surfaces so that the impacted supercooled water droplets could be blown away by the airflow from the airframe surface before being frozen into ice. It is of fundamental importance to understand the wind-driven runback behavior of water droplets over surfaces treated with different coatings, since the corresponding knowledge would be very helpful and essential to develop more efficient anti-/de-icing systems for aircraft icing protection. With the rapid development of surface engineering, a series of specially designed surface coatings succeed in icing mitigation using airflow to remove the remained water. While various hydro-/ice-phobic coatings/surfaces have been developed in recent years, the “state-of-the-art” icephobic coatings/surfaces can be generally divided into three categories, i.e., 1). Lotus-leaf-inspired superhydrophobic surfaces (SHS) with micro-/nano-scale surface textures to achieve very high contact angles (typically > 150°); 2). Pitcherplant-inspired slippery liquid infused porous surfaces (SLIPS) with a layer of liquid lubricant (which is immiscible with water) being sandwiched between ice and solid substrate materials; and 3). Icephobic elastic materials/surfaces with deformable structures/surfaces. SHS has a water droplet contact angle (CA) larger than 150° and a sliding angle (SA) less than 10° . SHS always has a hierarchical structure which is similar to the lotus leaf, and water droplets on SHS appear as water beads which can easily roll off the surface by wind or gravity before frozen. Another strategy to reduce ice adhesion strength to a solid surface is to use a layer of liquid lubricant, which is immiscible with water, between ice and the solid surface. The use of such lubricated surfaces was investigated as early as 1960s, and has gained increasing attentions again recently with the introduction of a concept called Slippery Liquid-Infused Porous Surfaces (SLIPS). SLIPS concept is inspired by the Nepenthes pitcher plants, which have evolved highly slippery, liquidinfused micro-textured rim to capture insects. SLIPS surfaces were not only found to be able to suppress ice/frost accretion by effectively removing condensed moisture even in high humidity conditions, but also exhibit at least an order of magnitude lower ice adhesion than most SHS coatings. More recently, elastic materials/surfaces, such as Polydimethylsiloxane or PDMS in short, which would be structurally deformed/altered dynamically upon applying extra mechanical stress, have also been suggested for icing mitigation. Elastic materials display ultra-low adhesion to ice due to their low work of adhesion and liquidlike deformability, while maintaining good mechanical durability due to their solid-like rigidity. It is found that water droplets would not only be more readily rebounding away from the surface after impingement, but also be able to roll away before frozen due to the hydrophobicity of PDMS. Considering the differences in wettabilities and mechanisms of water repellency, it is necessary to have a systematic understanding of how efficient the surfaces are when the aerodynamic force is applied to remove the adhered water droplets. In the present study, a comprehensive experimental campaign was conducted to characterize the transient runback behaviors of wind-driven water droplets over the surfaces of test plates coated with different hydro-/icephobic coatings (i.e., SHS, SLIPS and PDMS). A high-resolution Particle Image Velocimetry (PIV) system was used to achieve quantitative measurements of the velocity field of the airflow around the wind-driven water droplets on the test surfaces with different wettabilities. With the detailed PIV measurements of the airflow field around the runback water droplets and the droplet profiles, the aerodynamic forces and the adhesion forces acting on the water droplets were estimated. While Fig. 1 shows the experimental setup used in the present study, Fig. 2 to Fig. 3 given some of the typical measurement results. More measurement results and comprehensive analysis and discussions will be provided in the full version of this research paper.

Interaction phenomena of two water droplets successively impacting onto a solid surface

2008 ◽  
Vol 47 (3) ◽  
pp. 229-236 ◽  
Author(s):  
Hitoshi Fujimoto ◽  
Albert Y. Tong ◽  
Hirohiko Takuda
Keyword(s):  
Solid Surface ◽  
Water Droplets ◽  
Interaction Phenomena

Simulation of the shapes of a water droplet on insulated solid surface in an ACelectric field

2007 ◽  
Vol 85 (9) ◽  
pp. 911-926
Author(s):  
A Moukengué ◽  
S Ndjakomo Essiane ◽  
A Beroual
Keyword(s):  
Mathematical Model ◽  
Solid Surface ◽  
Water Droplet ◽  
Analytical Study ◽  
Three Dimensional ◽  
Dielectric Surface ◽  
Water Droplets ◽  
Droplet Deformation ◽  
Droplet Shape ◽  
Electric Stress

This paper presents an analytical study of the deformation of water droplets under AC electric stress. The droplet was located on a dielectric smooth solid surface between two plate electrodes. A mathematical model was developed as a basic framework for conducting a simulation of an axial-asymmetric elongation of a water droplet with a given volume. The model, which has three-dimensional axial-asymmetric droplet shapes, was elaborated by computing simultaneously two different halves of the axial-symmetric droplet shape. In that mathematical model and in the corresponding approach, the droplet deformation depends on a number of parameters; these include the volume of the droplet, its viscosity, conductivity, and permittivity, as well as the material of the dielectric surface used, the droplet location between both electrodes, and the dielectric surface. PACS Nos.:47.55.D–, 47.65.–d, 47.11.–j

Sign in / Sign up

Export Citation Format

Share Document