scholarly journals Bouncing-to-wetting transition for impact of water droplets on soft solids

Soft Matter ◽  
2021 ◽  
Author(s):  
Surjyasish Mitra ◽  
Quoc Vo ◽  
Tuan Tran
Keyword(s):  
Wetting Transition ◽  
Liquid Droplets ◽  
Water Droplets ◽  
Soft Solids ◽  
Air Film

Soft surfaces impacted by liquid droplets trap more air underneath than their rigid counterpart. The extended lifetime of the air film not only facilitates bouncing behaviours of the impacting droplets...

Fizzy water droplets levitate at room temperature

Physics World ◽  
2021 ◽  
Vol 34 (9) ◽  
pp. 7ii-7ii
Author(s):  
Isabelle Dumé
Keyword(s):  
Carbon Dioxide ◽  
Room Temperature ◽  
Deionized Water ◽  
Liquid Droplets ◽  
Water Droplets ◽  
Leidenfrost Effect ◽  
Gaseous Carbon Dioxide

Researchers have come up with a room-temperature way to recreate the Leidenfrost effect and levitate liquid droplets by pumping gaseous carbon dioxide into deionized water.

Freezing of micrometer-sized liquid droplets of pure water evaporatively cooled in a vacuum

2018 ◽  
Vol 20 (45) ◽  
pp. 28435-28444 ◽  
Author(s):  
Kota Ando ◽  
Masashi Arakawa ◽  
Akira Terasaki
Keyword(s):  
Pure Water ◽  
Ice Nucleation ◽  
Nucleation Theory ◽  
Liquid Droplets ◽  
Freezing Time ◽  
Water Droplets

The freezing time of pure-water droplets is measured in a vacuum and simulated by ice nucleation theory.

scholarly journals Dust removal from a hydrophobic surface by rolling fizzy water droplets

RSC Advances ◽  
2020 ◽  
Vol 10 (34) ◽  
pp. 19811-19821 ◽  
Author(s):  
Bekir Sami Yilbas ◽  
Ghassan Hassan ◽  
Hussain Al-Qahtani ◽  
Saeed Bahatab ◽  
Ahmet Z. Sahin ◽  
...  
Keyword(s):  
Removal Rate ◽  
Hydrophobic Surface ◽  
Dust Removal ◽  
Liquid Droplets ◽  
Water Droplets

Here, environmental dust cleaning from an inclined hydrophobic surface by rolling liquid droplets has been studied and the influence of fluid droplets on the dust removal rate has been examined.

scholarly journals Computational Analysis of Surface Curvature Effect on Mist Film-Cooling Performance

2008 ◽  
Vol 130 (12) ◽  
Author(s):  
Xianchang Li ◽  
Ting Wang
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Leading Edge ◽  
Operating Conditions ◽  
Curved Surfaces ◽  
Curvature Effect ◽  
Water Droplets ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Air Film

Air-film cooling has been widely employed to cool gas turbine hot components, such as combustor liners, combustor transition pieces, turbine vanes, and blades. Studies with flat surfaces show that significant enhancement of air-film cooling can be achieved by injecting water droplets with diameters of 5–10 μm into the coolant airflow. The mist/air-film cooling on curved surfaces needs to be studied further. Numerical simulation is adopted to investigate the curvature effect on mist/air-film cooling, specifically the film cooling near the leading edge and on the curved surfaces. Water droplets are injected as dispersed phase into the coolant air and thus exchange mass, momentum, and energy with the airflow. Simulations are conducted for both 2D and 3D settings at low laboratory and high operating conditions. With a nominal blowing ratio of 1.33, air-only adiabatic film-cooling effectiveness on the curved surface is lower than on a flat surface. The concave (pressure) surface has a better cooling effectiveness than the convex (suction) surface, and the leading-edge film cooling has the lowest performance due to the main flow impinging against the coolant injection. By adding 2% (weight) mist, film-cooling effectiveness can be enhanced approximately 40% at the leading edge, 60% on the concave surface, and 30% on the convex surface. The leading edge film cooling can be significantly affected by changing of the incident angle due to startup or part-load operation. The film cooling coverage could switch from the suction side to the pressure side and leave the surface of the other part unprotected by the cooling film. Under real gas turbine operating conditions at high temperature, pressure, and velocity, mist-cooling enhancement could reach up to 20% and provide a wall cooling of approximately 180 K.

scholarly journals Evaporation-Triggered Wetting Transition for Water Droplets upon Hydrophobic Microstructures

2010 ◽  
Vol 104 (11) ◽  
Author(s):  
Peichun Tsai ◽  
Rob G. H. Lammertink ◽  
Matthias Wessling ◽  
Detlef Lohse
Keyword(s):  
Wetting Transition ◽  
Water Droplets

Flow in Duct Downstream of a Steam Turbine Bypass Valve

2006 ◽  
Author(s):  
R. S. Amano
Keyword(s):  
Heat Transfer ◽  
Flow Pattern ◽  
Steam Turbine ◽  
Perforated Plate ◽  
Theoretical Models ◽  
Pipeline System ◽  
Evaporation Process ◽  
Liquid Droplets ◽  
Water Droplets ◽  
Generator System

The main goal of this study is to investigate the evaporation process of a coolant (water droplets) which is injected through spray nozzles mounted on a steam turbine bypass pipeline in a co-generator system. The study includes several important factors: (1) the effects of four elbows on the flow pattern and evaporation process of the water particles, (2) heat transfer that affects the steam temperature and also the evaporation rates, and (3) the effects of a perforated plate on the flow pattern and evaporation process. The investigation of the structure of liquid spray jets during the transition into the gaseous phase was accomplished by developing a physical model of a particle tracking technique to investigate evaporation processes of the liquid droplets in a highly turbulent flow. Through this research, numerous data have been acquired and analyzed for heat transfer mechanisms of the evaporation of the water droplets in the pipeline system along with the cooling of the steam flow. The results of the computations were verified by comparing them with theoretical models, and were shown to be quite reliable.

scholarly journals Numerical analysis of sulfur dioxide absorption in water droplets

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 104-111
Author(s):  
Tibor Bešenić ◽  
Milan Vujanović ◽  
Jakov Baleta ◽  
Klaus Pachler ◽  
Niko Samec ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Sulfur Dioxide ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flue Gases ◽  
Liquid Droplets ◽  
Water Droplets ◽  
Concentration Difference ◽  
Factors Affecting ◽  
Droplet Chemistry

AbstractMass transfer between the phases is a cornerstone of many technological processes and presents a topic whose understanding and modelling is of high importance. For instance, absorption of gases in liquid droplets is an underlying phenomenon for the desulfurization of flue gases in wet scrubbers. Wet scrubbing is an efficient cleaning method where the liquid is sprayed in a stream of rising gases, removing pollutants due to the concentration difference between the gas phase and droplets. A model for absorption in water droplets has been developed to describe the complex physical and chemical interactions during the exposure to flue gases. The main factors affecting the absorption are the mass transfer of pollutants through the gas–droplet interface and the aqueous phase chemistry in a droplet. The mass transfer coefficient, which has been modeled with several approaches, is the most significant parameter regulating the absorption dynamic into the droplet, while the in-droplet chemistry controls the maximum quantity of dissolved pollutants. Dissociation of sulfur dioxide and the chemical reactions in seawater have been described by the equilibrium reactions. Afterward, the influence of the mass transfer coefficient has been investigated, and the model has been validated against the literature data on a single droplet scale. Obtained results are comparable with the experimental measurements and indicate the applicability of the model for the design and development of industrial scrubbers.

scholarly journals Evaporation-Rate Control of Water Droplets on Flexible Transparent Heater for Sensor Application

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4918
Author(s):  
Jaesoung Park ◽  
Suhan Lee ◽  
Dong-Ik Kim ◽  
Young-You Kim ◽  
Samsoo Kim ◽  
...  
Keyword(s):  
Rate Control ◽  
High Performance ◽  
Evaporation Rate ◽  
Surface Wettability ◽  
Liquid Droplets ◽  
Water Droplets ◽  
Evaporation Time ◽  
Smart Windows ◽  
Sensor Applications ◽  
Cctv Camera

To develop high-performance de- or anti-frosting/icing devices based on transparent heaters, it is necessary to study the evaporation-rate control of droplets on heater surfaces. However, almost no research has been done on the evaporation-rate control of liquid droplets on transparent heaters. In this study, we investigate the evaporation characteristics of water droplets on transparent heater surfaces and determine that they depend upon the surface wettability, by modifying which, the complete evaporation time can be controlled. In addition, we study the defrosting and deicing performances through the surface wettability, by placing the flexible transparent heater on a webcam. The obtained results can be used as fundamental data for the transparent defrosting and deicing systems of closed-circuit television (CCTV) camera lenses, smart windows, vehicle backup cameras, aircraft windows, and sensor applications.

Numerical Analysis of Liquid Water Droplets Removal in Gas Channels of a PEM Fuel Cell

2010 ◽  
Author(s):  
Chin-Hsiang Cheng ◽  
Wei-Shan Han ◽  
Chun-I Lee ◽  
Huan-Ruei Shiu ◽  
Ssu-Tai Lin
Keyword(s):  
Contact Angle ◽  
Fuel Cell ◽  
Flow Velocity ◽  
Dynamic Behavior ◽  
Liquid Water ◽  
Pem Fuel Cell ◽  
Bipolar Plate ◽  
Incoming Flow ◽  
Liquid Droplets ◽  
Water Droplets

The present study is concerned with the dynamic behavior of the liquid water droplets in the water removal process in the serpentine channels of a PEM fuel cell based on computational fluid dynamic (CFD) simulation. The volume of fluid (VOF) model is adopted to trace the interface between the liquid and the gas phases such that the motion of the liquid droplets can be observed. Effects of the incoming velocity are evaluated. In addition, the surface hydrophobic properties are influential to the droplets motion; therefore, the contact angle of the liquid droplet attached on the channel wall has been varied. In addition, the orientation of the bipolar plate is regarded as another important parameter in the present study. Results show that among these parameters considered, the incoming flow velocity and the contact angle are two key parameters which greatly affect the dynamic behavior of the liquid droplets. The liquid droplets attached on the wall of the bipolar plate can be removed by the gas flow only when the contact angle or the incoming flow velocity is sufficiently high.

Sign in / Sign up

Export Citation Format

Share Document