Anti-icing agent releasing diatomaceous earth/SBS composites

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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Superhydrophobic and Highly Oleophilic Polystyrene Fibers (PS) with Delayed Freezing Time and Effective Oil Adsorption

Materials Science Forum ◽

10.4028/www.scientific.net/msf.941.2232 ◽

2018 ◽

Vol 941 ◽

pp. 2232-2236

Author(s):

Reza Jafari ◽

Marc Chameau ◽

Masoud Farzaneh ◽

Gelareh Momen

Keyword(s):

Contact Angle ◽

Superhydrophobic Surface ◽

Contact Angle Hysteresis ◽

Aluminum Surface ◽

Motor Oil ◽

Freezing Time ◽

Water Droplets ◽

Flexible Behavior ◽

Oil Adsorption ◽

Very High

We present an efficient and simple approach for preparing superhydrophobic-superoleophilic polystyrene (PS) fibers via electrospinning. Bead-on-string fibers from a 5% PS solution and micro-sized fibers from a 20% PS solution were combined to achieve a surface having very high contact angle (about 160°) and low contact angle hysteresis. The presence of bead-on-string fibers increases the superhydrophobicity of the sorbent. The micro-sized PS fibers improve the mechanical properties of the electrospun mat through their elastic and flexible behavior. An evaluation of wettability at a low temperature (-10 oC) showed a delayed freezing time for water droplets on the superhydrophobic surface. Water droplets on a polished aluminum surface froze more quickly (about 6 seconds) than droplets on the fabricated superhydrophobic surface (about 500 seconds). Finally, the oil adsorption capacity of the developed superhydrophobic PS fibers, which have a porous surface structure, showed values of 69.1, 69.3 and 61.2 g/g for canola oil, olive oil and motor oil, respectively.

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Experimental study of the internal flow in freezing water droplets on a cold surface

Experiments in Fluids ◽

10.1007/s00348-019-2823-1 ◽

2019 ◽

Vol 60 (12) ◽

Cited By ~ 4

Author(s):

Linn Karlsson ◽

Henrik Lycksam ◽

Anna-Lena Ljung ◽

Per Gren ◽

T. Staffan Lundström

Keyword(s):

Natural Convection ◽

Internal Flow ◽

Light Sheet ◽

Initial Time ◽

Freezing Time ◽

Water Droplets ◽

Cold Surface ◽

Time Period ◽

Image Velocimetry ◽

Marangoni Effects

Abstract The study of a freezing droplet is interesting in areas, where the understanding of build up of ice is important, for example, on wind turbines, airplane wings and roads. In this work, the main focus is to study the internal motion inside freezing water droplets using particle image velocimetry and to reveal if mechanisms such as natural convection and Marangoni convection have a noticeable influence on the flow within the droplet. The flow has successfully been visualized and measured for the first 25% of the total freezing time of the droplet when the velocity in the water is the highest and when the characteristic vortices can be seen. After this initial time period, the high amount of ice in the droplet scatters the PIV light sheet too much and the images retrieved are not suitable for analysis. Initially, it can be seen that the Marangoni effects have a large impact on the internal flow, but after about 15% of the total freezing time, the flow turns indicating increased effects of natural convection on the flow. Shortly after this time, almost no internal flow can be seen. Graphic abstract

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Waterborne, non-fluorinated and durable anti-icing superhydrophobic coatings based on diatomaceous earth

New Journal of Chemistry ◽

10.1039/d1nj01307f ◽

2021 ◽

Author(s):

Hua Xie ◽

Xia Zhao ◽

Bucheng Li ◽

Jiaojiao Zhang ◽

Jinfei Wei ◽

...

Keyword(s):

Diatomaceous Earth ◽

Mechanical Vibration ◽

Freezing Time ◽

Chemical Release ◽

Superhydrophobic Coatings

Superhydrophobic coatings have a great potential for anti-icing compared with conventional techniques (e.g., thermally melting, chemical release and mechanical vibration), but suffer from short water freezing time, environmentally unfriendness and...

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