The freezing process of continuously sprayed water droplets on the superhydrophobic silicone acrylate resin coating surface

Freezing water droplets are a natural phenomenon that occurs regularly in the Arctic climate. It affects areas such as aircrafts, wind turbine blades and roads, where it can be a safety issue. To further scrutinize the freezing process, the main objective of this paper is to experimentally examine the influence of substrate material on the internal flow of a water droplet. The secondary goal is to reduce uncertainties in the freezing process by decreasing the randomness of the droplet size and form by introducing a groove in the substrate material. Copper, aluminium and steel was chosen due to their differences in thermal conductivities. Measurements were performed with Particle Image Velociometry (PIV) to be able to analyse the velocity field inside the droplet during the freezing process. During the investigation for the secondary goal, it could be seen that by introducing a groove in the substrate material, the contact radius could be controlled with a standard deviation of 0.85%. For the main objective, the velocity profile was investigated during different stages of the freezing process. Five points along the symmetry line of the droplet were compared and copper, which also has the highest thermal conductivity, showed the highest internal velocity. The difference between aluminium and steel was in their turn more difficult to distinguish, since the maximum velocity switched between the two materials along the symmetry line.

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Artificial icing and AC flashover tests on glass insulators with silicone acrylate resin hydrophobic coatings

IEEE Transactions on Dielectrics and Electrical Insulation ◽

10.1109/tdei.2015.005464 ◽

2016 ◽

Vol 23 (2) ◽

pp. 1038-1047 ◽

Cited By ~ 9

Author(s):

Jianlin Hu ◽

Binhuan Lan ◽

Ke Xu ◽

Xingliang Jiang ◽

Zhijin Zhang ◽

...

Keyword(s):

Hydrophobic Coatings ◽

Acrylate Resin ◽

Silicone Acrylate

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Using linear and branched polysilanes for the photoinitiated polymerization of a commercial silicone-acrylate resin.

Journal of Photochemistry and Photobiology A Chemistry ◽

10.1016/s1010-6030(01)00424-5 ◽

2001 ◽

Vol 141 (1) ◽

pp. 85-91 ◽

Cited By ~ 17

Author(s):

Carmen Peinado ◽

Asunción Alonso ◽

Fernando Catalina ◽

Wolfram Schnabel

Keyword(s):

Photoinitiated Polymerization ◽

Acrylate Resin ◽

Silicone Acrylate

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In Situ Synthesis of Reduced Graphene Oxide-Reinforced Silicone-Acrylate Resin Composite Films Applied in Erosion Resistance

Journal of Nanomaterials ◽

10.1155/2015/405087 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Yang Cao ◽

Xiaoyong Tian ◽

Yan Wang ◽

Youyi Sun ◽

Hailin Yu ◽

...

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Erosion Resistance ◽

Resin Composite ◽

Composite Films ◽

In Situ Synthesis ◽

Reduced Graphene ◽

Acrylate Resin ◽

Silicone Acrylate

The reduced graphene oxide reinforced silicone-acrylate resin composite films (rGO/SAR composite films) were prepared by in situ synthesis method. The structure of rGO/SAR composite films was characterized by Raman spectrum, atomic force microscope, scanning electron microscopy, and thermogravimetric analyzer. The results showed that the rGO were uniformly dispersed in silicone-acrylate resin matrix. Furthermore, the effect of rGO loading on mechanical properties of composite films was investigated by bulge test. A significant enhancement (ca. 290% and 320%) in Young’s modulus and yield stress was obtained by adding the rGO to silicone-acrylate resin. At the same time, the adhesive energy between the composite films and metal substrate was also improved to be about 200%. Moreover, the erosion resistance of the composite films was also investigated as function of rGO loading. The rGO had great effect on the erosion resistance of the composite films, in which theRcorr(ca. 0.8 mm/year) of composite film was far lower than that (28.7 mm/year) of pure silicone-acrylate resin film. Thus, this approach provides a novel route to investigate mechanical stability of polymer composite films and improve erosion resistance of polymer coating, which are very important to be used in mechanical-corrosion coupling environments.

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Numerical Simulation of Water Droplet Freezing Process on Cold Surface

Volume 8: Heat Transfer and Thermal Engineering ◽

10.1115/imece2017-71175 ◽

2017 ◽

Author(s):

Yina Yao ◽

Cong Li ◽

Zhenxiang Tao ◽

Rui Yang

Keyword(s):

Contact Angle ◽

Numerical Model ◽

Phase Change ◽

Empirical Relation ◽

Three Dimensional ◽

Freezing Process ◽

Freezing Time ◽

Water Droplets ◽

Cold Surface ◽

Extended Phase

It is significant to clearly understand the freezing process of water droplets on a cold substrate for the prevention of ice accretion. In this study, a three-dimensional numerical model including an extended phase change method was developed on OpenFOAM platform to simulate the freezing of static water droplets on cooled solid substrates. The predicted freezing process was compared with numerical results obtained by others. Good agreements were obtained and our numerical model results in faster convergence compared to the traditional phase change method. The effects of surface wettability on freezing time and freezing velocity were numerically investigated. The results show that the freezing time presents a positive relationship with contact angle due to the smaller contact area with higher contact angle, which agrees well with the theoretical analysis. Besides, the empirical relation between freezing time and contact angle were obtained.

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Numeric modeling of a micro-scale differential thermal calorimeter for the purpose of cryopreservation

10.32469/10355/63519 ◽

2017 ◽

Author(s):

◽

Han Han

Keyword(s):

Heat Flux ◽

Temperature Distribution ◽

Cooling Rate ◽

Water Droplet ◽

Biological Material ◽

Computational Time ◽

Freezing Process ◽

Water Droplets ◽

Micro Scale ◽

Numeric Model

Cryopreservation requires biological material to be stored at temperatures well below the freezing point of water. During the process of cryopreservation, the cooling rate should be carefully chosen to avoid cell damage due to the unbalanced pressure and the solution effect. Cellular thermal analysis that determines the thermodynamics properties of a micro-scale biological material is necessary for a successful cryopreservation procedure. A micro-scale differential thermal analyzer (uDTA) was previously developed to obtain accurate thermal properties measurements of freezing cells. However, the thermal signal needs to be properly interpreted in terms of how much ice is created. Also, the future cooling profile needed to experimentally control the cooling rate needs to be developed. So a 3D numeric model was built in STAR CCM+ to study the temperature change of the water droplets while being frozen by a thermoelectric module. The heat flux profile for the boundary condition was scaled to accommodate the heat spread effect. The numeric model solutions successfully matched the temperature distribution results from the experiments. By using additional heat flux to accommodate the heat spread effect, the STAR CCM+ model generated relatively accurate results on a smaller geometry within a very short computational time. This is a big improvement compared with other high fidelity computational simulation models used to solve similar problems. After the 3D model was calibrated, the same STAR CCM+ model was used to predict the temperature distribution of different sizes of water droplets during the freezing process. This model allowed us to better understand the temperature distribution of a water droplet when the water droplet was being cooled until frozen. The modeling technique developed in this research will help establish the required cooling rates needed to control ice formation and establish thermodynamic properties of cell freezing solutions.

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Experimental Research on Improving Wear Resistance of Coating Surface by Magnetron Sputtering

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.9 ◽

2011 ◽

Vol 189-193 ◽

pp. 9-12 ◽

Cited By ~ 5

Author(s):

Yue Hao Luo ◽

De Yuan Zhang ◽

Hua Wei Chen

Keyword(s):

Wear Resistance ◽

Magnetron Sputtering ◽

Epoxy Resin ◽

Carbon Film ◽

Friction Reduction ◽

Coating Surface ◽

Resin Coating ◽

Epoxy Resin Coating ◽

Different Levels

Magnetron sputtering metallic or non-metallic materials on epoxy resin coating surface can effectively reduce the friction, improve the wear resistance and inhibit the abrasion, loss and so on. Sputtering Ti/C on the epoxy resin coating can modify the surface, it is proved that the friction can be reduced and wear resistance can be improved on different levels by the experimental results, and in this paper, the mechanism of friction reduction and wear resistance improvement is also investigated and researched comprehensively. By analysis, the layered structure produced by sputtering C can play an important role of lubricating, and the diamond film or diamond-like carbon film can exist on the coating surface, which can play an important role of wear resistance. This study lays the foundation for research on the modification of coating surface.

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Comparing Internal Flow in Freezing and Evaporating Water Droplets Using PIV

Water ◽

10.3390/w12051489 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1489

Author(s):

Linn Karlsson ◽

Anna-Lena Ljung ◽

T. Staffan Lundström

Keyword(s):

Natural Convection ◽

Marangoni Convection ◽

Flow Direction ◽

Flow Behavior ◽

Internal Flow ◽

Freezing Process ◽

Complex Nature ◽

Water Droplets ◽

Wide Range ◽

Jet Printing

The study of evaporation and freezing of droplets is important in, e.g., spray cooling, surface coating, ink-jet printing, and when dealing with icing on wind turbines, airplane wings, and roads. Due to the complex nature of the flow within droplets, a wide range of temperatures, from freezing temperatures to heating temperatures, have to be taken into account in order to increase the understanding of the flow behavior. This study aimed to reveal if natural convection and/or Marangoni convection influence the flow in freezing and evaporating droplets. Droplets were released on cold and warm surfaces using similar experimental techniques and setups, and the internal flow within freezing and evaporating water droplets were then investigated and compared to one another using Particle Image Velocimetry. It was shown that, for both freezing and evaporating droplets, a shift in flow direction occurs early in the processes. For the freezing droplets, this effect could be traced to the Marangoni convection, but this could not be concluded for the evaporating droplets. For both evaporating and freezing droplets, after the shift in flow direction, natural convection dominates the flow. In the end of the freezing process, conduction seems to be the only contributing factor for the flow.

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UV Curable Heat Resistant Epoxy Acrylate Coatings

Chemistry & Chemical Technology ◽

10.23939/chcht04.03.205 ◽

2010 ◽

Vol 4 (3) ◽

pp. 205-216

Author(s):

Firdous Habib ◽

◽

Madhu Bajpai ◽

Keyword(s):

Heat Resistance ◽

Chemical Resistance ◽

Polymeric Materials ◽

Organic Polymer ◽

Epoxy Acrylate ◽

Uv Curable ◽

Heat Resistant ◽

Acrylate Resin ◽

Physical And Chemical ◽

Silicone Acrylate

Polymeric materials are exposed to high temperatures that results in lowering of the film integrity. A blend of an epoxy resin with the silicone acrylate resin was developed to provide high heat resistance UV cured coatings. Earlier siliconized epoxy coatings had been developed by conventional curing. But due to environmental awareness, high productivity rate, low process costs and energy saving UV curable coatings are enjoying considerable growth. Thermally stable UV cured coatings used in the present study were developed from silicone acrylate and epoxy acrylate resin with different diluents and photoinitiator. Such coatings provide higher thermal stability (693 K) along with physical and chemical resistance. In addition, such coatings can also be obtained by using functional amino silanes. The resin developed provides a simple and practical solution to improve heat resistance along with physical and chemical resistance of the UV cured coatings. The purpose of this research paper is to develop UV curable heat resistant coatings by the combination of inorganic and organic polymer, taking epoxy acrylate as a base resin.

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