Effect of contact angle on water droplet freezing process on a cold flat surface

Huang, Lei; Liu, Zhongliang; Liu, Yao-Min; Gou, Yonggang; Wang, Li

doi:10.1016/j.expthermflusci.2012.02.002

Cited by 129 publications

(64 citation statements)

References 14 publications

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“…Because the drop height increases, the solidification process takes longer time to complete as the contact angle increases in the range of 45 • to 120 • , as shown in Figure 7b. This tendency is the same as the experimental observations (e.g., for water [1]). In addition, the volume expansion increases time for complete solidification.…”

Section: Resultssupporting

confidence: 77%

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Direct Numerical Study of a Molten Metal Drop Solidifying on a Cold Plate with Different Wettability

Nguyen

Khanh

2018

Metals

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This paper presents a direct numerical simulation of solidification of a molten metal drop on a cold plate with various wettability by an axisymmetric front-tracking method. Because of the plate kept at a temperature below the fusion value of the melt, a thin solid layer forms at the plate and evolves upwards. The numerical results show that the solidifying front is almost flat except near the triple point with a high solidification rate at the beginning and final stages of solidification. Two solid-to-liquid density ratios ρ sl = 0.9 (volume change) and 1.0 (no change in volume), with two growth angles φ 0 = 0 • and 12 • are considered. The presence of volume change and a non-zero growth angle results in a solidified drop with a conical shape at the top. The focusing issue is the effects of the wettability of the plate in terms of the contact angle φ 0 . Increasing the contact angle in the range of 45 • to 120 • increases time for completing solidification, i.e., solidification time. However, it has a minor effect on the conical angle at the top of the solidified drop and the difference between the initial liquid and final solidified heights of the drop. The effects of the density ratio and growth angle are also presented.

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Section: Resultssupporting

confidence: 77%

“…Experimentally, Huang et al [1] investigated freezing of water drops on a cold plate under various contact angles (in the range of 76-154.9 • ). They found that the contact angle has a remarkable effect on the water drop freezing time: it increases with an increase in the contact angle.…”

Section: Introductionmentioning

confidence: 99%

Direct Numerical Study of a Molten Metal Drop Solidifying on a Cold Plate with Different Wettability

Nguyen

Khanh

2018

Metals

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“…[6], the effect of an inclined surface [7][8][9], internal heat transfer [10,11] and internal flow [12]. A number of studies have also experimentally shown that the contact angle, θ, has a strong influence on the water droplet freezing time, t f [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Modelling the dynamics of the flow within freezing water droplets

2018

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The flow within freezing water droplets is here numerically modelled assuming fixed shape throughout freezing. Three droplets are studied with equal volume but different contact angles and two cases are considered, one including internal natural convection and one where it is excluded, i.e. a case where the effects of density differences is not considered. The shape of the freezing front is similar to experimental observations in the literature and the freezing time is well predicted for colder substrate temperatures. The latter is found to be clearly dependent on the plate temperature and contact angle. Including density differences has only a minor influence on the freezing time, but it has a considerable effect on the dynamics of the internal flow. To exemplify, in the vicinity of the density maximum for water (4 • C) the velocities are about 100 times higher when internal natural convection is considered for as compared to when it is not.

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“…Therefore, the ice accumulates in the form of ice bulges. 24 This paper seeks to analyze the influence of different ice accumulation forms on heat dissipation under wind condition. Simulation results presented in section II B indicate that the hydrophobicity and wind speed have very limited effect on the cooling rate of single droplet under wind condition; therefore, …”

Section: Heat Dissipation During Ice Accumulationmentioning

confidence: 99%

Influence of hydrophobicity on ice accumulation process under sleet and wind conditions

Shu

et al. 2018

AIP Advances

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Glaze, the most dangerous ice type in natural environment, forms during sleet weather, which is usually accompanied with wind. The icing performance of hydrophobic coatings under the impact of wind needs further research. This paper studies the influence of hydrophobicity on ice accumulation process under sleet and wind conditions by computer simulations and icing tests. The results indicate that the heat dissipation process of droplets on samples with various hydrophobicity will be accelerated by wind significantly and that a higher hydrophobicity cannot reduce the cooling rate effectively. However, on different hydrophobic surfaces, the ice accumulation process has different characteristics. On a hydrophilic surface, the falling droplets form continuously water film, which will be cooled fast. On superhydrophobic surface, the frozen droplets form ice bulges, which can shield from wind and slow down the heat dissipation process. These ice accumulation characteristics lead to the difference in ice morphology and make a higher hydrophobic surface to have a lower ice mass growth rate in long period icing tests. As a conclusion, superhydrophobic coating remain icephobic under wind and sleet conditions.

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Effect of contact angle on water droplet freezing process on a cold flat surface

Cited by 129 publications

References 14 publications

Direct Numerical Study of a Molten Metal Drop Solidifying on a Cold Plate with Different Wettability

Direct Numerical Study of a Molten Metal Drop Solidifying on a Cold Plate with Different Wettability

Modelling the dynamics of the flow within freezing water droplets

Influence of hydrophobicity on ice accumulation process under sleet and wind conditions

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