Study on the wettability and condensation heat transfer of sine-shaped micro-grooved surfaces

Qi, Baojin; Zhou, Jiasen; Wei, Jinjia; Li, Xiang

doi:10.1016/j.expthermflusci.2017.09.002

Cited by 31 publications

(11 citation statements)

References 24 publications

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“…The study for the wettability and condensation heat transfer of sine-shaped micro-grooved surfaces was carried out by Qi et al . 10 . They showed that the net force and the sliding velocity increased as droplets grow, and larger geometrical size was favorable to droplets falling.…”

Section: Introductionmentioning

confidence: 99%

A Water Droplet Pinning and Heat Transfer Characteristics on an Inclined Hydrophobic Surface

Al‐Sharafi

Yilbaş

Ali

et al. 2018

Sci Rep

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A water droplet pinning on inclined hydrophobic surface is considered and the droplet heat transfer characteristics are examined. Solution crystallization of polycarbonate is carried out to create hydrophobic characteristics on the surface. The pinning state of the water droplet on the extreme inclined hydrophobic surface (0° ≤ δ ≤ 180°, δ being the inclination angle) is assessed. Heat transfer from inclined hydrophobic surface to droplet is simulated for various droplet volumes and inclination angles in line with the experimental conditions. The findings revealed that the hydrophobic surface give rise to large amount of air being trapped within texture, which generates Magdeburg like forces between the droplet meniscus and the textured surface while contributing to droplet pinning at extreme inclination angles. Two counter rotating cells are developed for inclination angle in the range of 0° < δ < 20° and 135° < δ < 180°; however, a single circulation cell is formed inside the droplet for inclination angle of 25° ≤ δ ≤ 135°. The Nusselt number remains high for the range of inclination angle of 45° ≤ δ ≤ 135°. Convection and conduction heat transfer enhances when a single and large circulation cell is formed inside the droplet.

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Section: Introductionmentioning

confidence: 99%

A Water Droplet Pinning and Heat Transfer Characteristics on an Inclined Hydrophobic Surface

Al‐Sharafi

Yilbaş

Ali

et al. 2018

Sci Rep

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“…A hierarchical superhydrophobic surface comprising three-dimensional nanowired networks showed stable and efficient droplet jumping at a larger subcooling of up to 28 K in a pure steam environment . Recent studies showed an enhancement in heat-transfer performance on hybrid surfaces such as microgrooved surfaces, − millimetric-sized grooves, surfaces with geometric or thermal discontinuities, and heterogeneous surfaces with a wettability gradient. , The incorporation of hydrophilic/superhydrophilic patches is a promising approach to reducing the nucleation energy barrier on the superhydrophobic/hydrophobic surface. , The optimized design of a wettability-patterned surface with hydrophilic/superhydrophilic patches can show substantially higher condensation performance than the homogeneous surface due to enhanced drop nucleation and drop drainage. − In another study, a vertical hydrophilic surface with hydrophobic bumps showed an enhancement in condensation performance, owing to the droplet falling from the hydrophobic bumps, which results in the disturbance of the NCG layer …”

Section: Introductionmentioning

confidence: 99%

Condensation of Humid Air on Superhydrophobic Surfaces: Effect of Nanocoatings on a Hierarchical Interface

Thomas

Mahapatra

2021

Langmuir

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Vapor condensation is a well-known phase-change phenomenon observed in nature as well as in different industrial applications. Superhydrophobic surfaces (SHSs) with low hysteresis can efficiently drain off the condensate and rejuvenate the nucleation sites further. In this work, three distinct SHSs were fabricated by nanocoating three hydrophobic agents, viz., perfluoro-octyl-triethoxy-silane (PFOTS), perfluoro-octanoic-acid (PFOA), and commercial Glaco solution on a hierarchical aluminum surface. The surface morphology of all surfaces was investigated, and its effects on the wetting, droplet departure, and overall heat-transfer coefficient (HTC) during condensation phenomena in the humid air (>95% noncondensable gases) were analyzed. The contact angle hysteresis of all three surfaces was very low (∼5°); however, different wetting behaviors were observed during the condensation, depending on the adhesion of the condensate drop with nanoscale textures in the microcavities. Dropwise condensation (DWC) was observed in silane and Glaco-coated surfaces. A gravity-assisted sweeping mechanism removed the condensate from the silane-coated surface. In contrast, the condensate was ejected out of the plane of the Glaco-coated surface by droplet jumping. The PFOA-coated surface has shown DWC initially and floods in the later stages due to highly pinned condensed droplets. This study reports an enhancement of ∼35 to ∼110% in the HTC for the SHS-exhibiting gravity-assisted sweeping mechanism compared to the droplet-jumping mechanism. The present work will provide substantial insights into the fabrication of efficient hierarchical interfaces for water-energy nexus applications.

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“…The adhesion of hydrophobic surfaces to water is less than their cohesion, so the static contact angle is greater than 90°, making the surface exhibit water repellency. Among them, the superhydrophobic surfaces have excellent water repellency, with static contact angles of greater than 150° and contact angle hysteresis of less than 10°. − This superhydrophobicity is shown in many animals and plants in nature, such as lotus leaves, roses, and water strider legs. − Studies have shown that the unique properties of superhydrophobic surfaces endow it with good application prospects in many fields, such as phase-change heat-transfer enhancement, , flow drag reduction, self-cleaning, , anticorrosion, oil–water separation, , anti-icing and antifrosting, , and biological adhesion prevention . Therefore, the preparation of superhydrophobic surfaces has attracted much research attention.…”

Section: Introductionmentioning

confidence: 99%

Convenient and large-scale fabrication of cost-effective superhydrophobic aluminum alloy surface with excellent reparability

Cui

Cao

et al. 2021

Langmuir

Self Cite

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Superhydrophobic surfaces are widely used in industry and daily life, yet their practical application is limited by their complicated preparation process, high cost, and poor repairability. We propose a low-cost, facile process for preparing superhydrophobic surfaces to address this limitation. Through a simple three-step spraying process, the rough structure was first constructed on the aluminum alloy, and upon modification by modifier, the superhydrophobic aluminum alloy surface was successfully prepared. The effect of the process parameters on wettability was experimentally studied. The results showed that this method can obtain superhydrophobic surfaces with a contact angle of 156.2°and contact angle hysteresis of 7.4°by simply adjusting the etching time and modifier concentration. In addition, it was found that the prepared surface can keep the superhydrophobic property unchanged at 180 °C, showing good thermal stability. When immersed in acetic acid and sodium hydroxide solution, the prepared surface can maintain its superhydrophobicity for about 2 days, showing good chemical stability. Besides, the surface has excellent repairability and can compensate for the short-life defects caused by poor friction resistance. This superhydrophobic surface with a simple preparation process, low cost, and excellent repairable characteristics also has excellent selfcleaning, antifogging, and antifrosting applications.

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Study on the wettability and condensation heat transfer of sine-shaped micro-grooved surfaces

Cited by 31 publications

References 24 publications

A Water Droplet Pinning and Heat Transfer Characteristics on an Inclined Hydrophobic Surface

A Water Droplet Pinning and Heat Transfer Characteristics on an Inclined Hydrophobic Surface

Condensation of Humid Air on Superhydrophobic Surfaces: Effect of Nanocoatings on a Hierarchical Interface

Convenient and large-scale fabrication of cost-effective superhydrophobic aluminum alloy surface with excellent reparability

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