Research On Non-boiling Evaporation Behavior of Fixed Droplets On Aluminum Plate Surface

2021 ◽  
Author(s):  
Liansheng Liu ◽  
Xuanchen Liu ◽  
Wenjia Ren ◽  
Hongbin Duan ◽  
Runze Duan ◽  
...  
Keyword(s):  
Contact Angle ◽  
Evaporation Rate ◽  
Aluminum Plate ◽  
Initial Contact ◽  
Plate Surface ◽  
Evaporation Time ◽  
Plate Temperature ◽  
Initial Contact Angle ◽  
Initial Volume ◽  
Contact Diameter

Abstract In this paper, the non-boiling evaporation (30 -70?) of the fixed droplets on the Aluminum plate surface was investigated by the experiment. The effect of the plate temperature and initial volume on the contact angle, contact diameter and evaporation time were considered. The results showed that the temperature and initial volume were important for the droplets evaporation. As the heating plate temperature increased, the evaporation rate increased and the initial contact angle decreased. At the same heating plate temperature, the evaporation rate and the initial contact angle decreased with the increase of the droplets initial volume. At the constant temperature hydrophilic surface, the droplet evaporation is performed in two modes: Constant contact radius mode (CCR mode) and mix mode. The CCR mode were about 90% of the time at the droplets evaporation process and the droplet contact diameters kept constant with the increase of the evaporation time. For the mix mode, the contact angle and contact diameter decreased with the increase of the evaporation time.

Initial Contact Angle of the Foot Segment and GRF Components by the Gender Differences

2018 ◽  
Vol 57 (2) ◽  
pp. 625-633
Author(s):  
Sangheon Park ◽  
Sukhoon Yoon ◽  
Sang-Kyoon Park ◽  
Jiseon Ryu
Keyword(s):  
Gender Differences ◽  
Contact Angle ◽  
Initial Contact ◽  
Initial Contact Angle

WATER DROPLET EVAPORATION IN A CHAMBER ISOLATED FROM THE EXTERNAL ENVIRONMENT

2020 ◽  
Vol 6 (3) ◽  
pp. 8-22
Author(s):  
KSENIA A. Batishcheva ◽  
ATLANT E. Nurpeiis
Keyword(s):  
Water Vapor ◽  
Evaporation Rate ◽  
External Environment ◽  
Heat Removal ◽  
Droplet Evaporation ◽  
Droplet Volume ◽  
Evaporation Time ◽  
Aluminum Alloy Amg6 ◽  
Evaporation Of Droplets ◽  
Contact Diameter

With an increase in the productivity of power equipment and the miniaturization of its components, the use of traditional thermal management systems becomes insufficient. There is a need to develop drip heat removal systems, based on phase transition effects. Cooling with small volumes of liquids is a promising technology for microfluidic devices or evaporation chambers, which are self-regulating systems isolated from the external environment. However, the heat removal during evaporation of droplets into a limited volume is a difficult task due to the temperature difference in the cooling device and the concentration of water vapor that is unsteady in time depending on the mass of the evaporated liquid. This paper presents the results of an experimental study of the distilled water microdrops’ (5-25 μl) evaporation on an aluminum alloy AMg6 with the temperatures of 298-353 K in an isolated chamber (70 × 70 × 30 mm3) in the presence of heat supply to its lower part. Based on the analysis of shadow images, the changes in the geometric dimensions of evaporating drops were established. They included the increase in the contact diameter, engagement of the contact line due to nano roughening and chemical composition inhomogeneous on the surface (90-95% of the total evaporation time) of the alloy and a decrease in the contact diameter. The surface temperature and droplet volume did not affect the sequence of changes in the geometric dimensions of the droplets. It was found that the droplet volume has a significant effect on the evaporation time at relatively low substrate temperatures. The results of the analysis of droplet evaporation rates and hygrometer readings have shown that reservoirs with salt solutions can be used in isolated chambers to control the concentration of water vapor. The water droplets evaporation time was determined. The analysis of the time dependences of the evaporation rate has revealed that upon the evaporation of droplets in an isolated chamber under the conditions of the present experiment, the air was not saturated with water vapor. The latter did not affect the evaporation rate.

scholarly journals Noncovalent Spiropyran Coatings for Photoinduced Wettability Switching

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Matthias Bremer ◽  
Ruprecht Reinke ◽  
Britta Hesseler ◽  
Mohammadreza Taale ◽  
Daniela Ingwersen ◽  
...  
Keyword(s):  
Contact Angle ◽  
Uv Light ◽  
Green Light ◽  
Casting Process ◽  
Initial Contact ◽  
Initial Contact Angle ◽  
Candle Soot ◽  
Angle Difference ◽  
Coating Procedure ◽  
Microscopy Images

The noncovalent binding of spiropyran to candle-soot-covered surfaces is investigated for wettability switching using a coating procedure realized with a drop casting process of using 0.001 mol/L spiropyran in a 5 : 1 toluene-acetone mixture. Scanning electron microscopy images reveal a resulting surface with spiropyran flakes in the candle soot. A reversible switching with UV light and blue or green light is achieved, starting from an initial contact angle of 130°  ± 9.68°. The highest contact angle difference is 41° and reversibility has been shown for several switching cycles. Hence, our methods provide an easy-to-use strategy to generate surfaces with switchable wettability.

scholarly journals Effect of Glow-Discharge Plasma Treatment on Contact Angle and Micromorphology of Bamboo Green Surface

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1293
Author(s):  
Xuehua Wang ◽  
Kenneth J. Cheng
Keyword(s):  
Electron Microscopy ◽  
Contact Angle ◽  
Glow Discharge ◽  
Plasma Treatment ◽  
Discharge Plasma ◽  
Glow Discharge Plasma ◽  
Initial Contact ◽  
Initial Contact Angle ◽  
Utilization Ratio ◽  
Scanning Electron

The inner and outer surfaces of bamboo stems are usually removed prior to the manufacture of bamboo panels because the surfaces are hydrophobic and difficult to bond with glue. Hence, the recovery and utilization ratio of bamboo during processing is low. This study focused on using glow-discharge plasma to treat green bamboo surfaces to make them less hydrophobic. The effects of plasma treatment on green bamboo stems were examined using contact goniometry (wettability), non-contact confocal profilometry and scanning electron microscopy (SEM). Confocal profilometry and SEM revealed that the morphology of green bamboo surfaces varied between 3 different stems. Plasma was able to etch bamboo green surfaces, and make them rougher and more powdery. Plasma treatment was effective at converting green bamboo surfaces from hydrophobic (initial contact angle >110°) to hydrophilic (contact angle <20°). However, this effect was temporary and contact angle increased with time and recovered approximately 30% of its original value after 24 h. Based on our findings, we conclude that plasma treatment can alter parameters such as surface energy and roughness that could improve glue bonding of green bamboo, but delays between plasma treatment and further processing would need to be minimized.

Dependence of the structure of ring-shaped deposits resulting from evaporation of dispersion droplets on initial contact angle

2016 ◽  
Vol 78 (5) ◽  
pp. 633-640 ◽  
Author(s):  
S. P. Molchanov ◽  
V. I. Roldughin ◽  
I. A. Chernova-Kharaeva ◽  
G. A. Yurasik
Keyword(s):  
Contact Angle ◽  
Initial Contact ◽  
Initial Contact Angle

Transient Interface Shape and Deposition Profile Left by Desiccation of Colloidal Droplets on Multiple Surfaces

2015 ◽  
Author(s):  
Peter D. Dunning ◽  
Collin T. Burkhart ◽  
Michael J. Schertzer
Keyword(s):  
Contact Angle ◽  
Electric Fields ◽  
Particle Deposition ◽  
Medical Diagnostics ◽  
Initial Contact ◽  
Interface Shape ◽  
Deposition Pattern ◽  
Deposition Patterns ◽  
Contact Line Pinning ◽  
Contact Diameter

Control of deposition patterns left by desiccated colloidal droplets is valuable in applications ranging from medical diagnostics to inkjet printing. This investigation presents an experimental method to monitor the transient interface shape of a colloidal droplet during desiccation and to quantify the deposition pattern left by the colloidal material optically. Transient image profiles and particle deposition patterns are examined for droplets containing fluorescent particles that were desiccated on glass and on the photoresist SU-8 3005. Contact line pinning was more prevalent on glass, where the contact diameter remained approximately constant throughout the process and the contact angle decreased with time. On SU-8, the contact diameter was initially constant, but decreased after the contact angle was reduced. The initial contact diameter on glass was similar to the diameter of the deposition pattern. The diameter of the deposition pattern on SU-8 was approximately half of the initial contact diameter. The deposition on SU-8 was also observed to be more uniform than that left on glass. These results suggest that selection of an appropriate substrate is an important consideration for colloidal deposition. The method presented will be used to in future investigations to characterize the effectiveness of coffee stain suppression through the application of external electric fields.

Controlling the contact angle of biological sessile drops for study of their desiccated cracking patterns

2018 ◽  
Vol 6 (37) ◽  
pp. 5867-5875 ◽  
Author(s):  
Ruoyang Chen ◽  
Liyuan Zhang ◽  
Wei Shen
Keyword(s):  
Contact Angle ◽  
Initial Contact ◽  
Initial Contact Angle ◽  
Sessile Drops

Controlling the initial contact angle of biological sessile drops to advance the study and applications of their desiccated cracking patterns.

Measurement of Liquid Droplet Evaporation Rate under the Conditions of Intense Heating

2014 ◽  
Vol 698 ◽  
pp. 603-608 ◽  
Author(s):  
Evgenija Orlova ◽  
Dmitriy Feoktistov
Keyword(s):  
Contact Angle ◽  
Contact Line ◽  
Evaporation Rate ◽  
Liquid Droplet ◽  
Droplet Evaporation ◽  
Solid Substrate ◽  
Anodized Aluminum ◽  
Specific Evaporation Rate ◽  
Contact Line Pinning ◽  
Contact Diameter

This paper presents an experimental study of the evaporation of a sessile water-sodium chlorides solution drop to open atmosphere on the solid substrate (anodized aluminum) under the varying heat flux. The main parameters defining drop profile, i. e., contact diameter, contact angle, and height of the drop have been obtained. Specific evaporation rate has been calculated. According to the data analysis it was found, that the sessile water-sodium chlorides solution drop with the highest concentration (16.7%) evaporates in the "reverse depinning" mode. So, there is movement of the contact line in the direction of increasing the surface occupied by the drop. The sessile water and water-sodium chlorides solution drop with 4.8% and 9.1% concentration evaporates in the contact line pinning mode. The influence of the initial concentration of the evaporated solution on the contact angle and the specific evaporation rate was found out.

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