Experimental study of condensation heat transfer on a horizontal aluminum tube with superhydrophobic characteristic

Ji, Dae-Yun; Lee, Jeong‐Won; Hwang, Woonbong; Lee, Kwon-Yeong

doi:10.1016/j.ijheatmasstransfer.2019.01.040

Cited by 22 publications

(28 citation statements)

References 22 publications

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“…Owing to the difference between the saturated water vapor pressure at the surface temperature of the substrate ( P wall ) and the water vapor pressure at the surface temperature of the droplet ( P vapor ), a high degree of supersaturation ( S ) forms at the droplet–surface interface. Specifically, S represents the surface-temperature-dependent ratio of the actual and saturated water vapor pressures and it has been proposed as a metric for evaluating the condensation phenomenon [ 36 , 39 , 44 ]. It is expressed as the following.…”

Section: Resultsmentioning

confidence: 99%

“…When the degree of supersaturation increases, the superhydrophobicity becomes unstable, causing any improvements to the condensation heat exchange performance to be lost [ 30 , 31 , 32 , 33 ]. In order to address this issue, several studies have explored techniques to control the degree of supersaturation so that superhydrophobicity can be maintained [ 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ].…”

Section: Introductionmentioning

confidence: 99%

“…In a separate study, Ji et al fabricated a replica of an actual condenser environment and compared the condensation heat transfer performance for various supersaturation conditions using a condenser tube with a superhydrophobic surface. Their experiments proved that there is a range of supersaturation in which the condensation heat transfer performance can be improved by applying a superhydrophobic surface [ 39 ]. Furthermore, in a previous study, our research team defined the concept of the droplet behavior (DB) map and proposed a simple experimental method from which the supersaturation condition is inferred according to the difference between the surface temperature and the droplet temperature.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of Surface Structure Complexity on Interfacial Droplet Behavior of Superhydrophobic Titanium Surfaces for Robust Dropwise Condensation

Jeong

Lee

et al. 2021

Materials

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In general, the dropwise condensation supported by superhydrophobic surfaces results in enhanced heat transfer relative to condensation on normal surfaces. However, in supersaturated environments that exceed a certain supersaturation threshold, moisture penetrates the surface structures and results in attached condensation, which reduces the condensation heat transfer efficiency. Therefore, when designing superhydrophobic surfaces for condensers, the surface structure must be resistant to attached condensation in supersaturated conditions. The gap size and complexity of the micro/nanoscale surface structure are the main factors that can be controlled to maintain water repellency in supersaturated environments. In this study, the condensation heat exchange performance was characterized for three different superhydrophobic titanium surface structures via droplet behavior (DB) mapping to evaluate their suitability for power plant condensers. In addition, it was demonstrated that increasing the surface structure complexity increases the versatility of the titanium surfaces by extending the window for improved heat exchange performance. This study demonstrates the usefulness of DB mapping for evaluating the performance of superhydrophobic surfaces regarding their applicability for industrial condenser systems.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Surface Structure Complexity on Interfacial Droplet Behavior of Superhydrophobic Titanium Surfaces for Robust Dropwise Condensation

Jeong

Lee

et al. 2021

Materials

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“…Therefore, the merged droplet is more easily detached from the superhydrophobic surface, leading to enhanced condensation heat transfer performance. Ji et al [ 124 ] investigated the condensation heat transfer performance on superhydrophobic and bare aluminum surfaces. The visual experiment of dropwise, flooded, and attached condensation was conducted, as shown in Figure 27 .…”

Section: Condensation Heat Transfer On Superhydrophobic Surfacesmentioning

confidence: 99%

A Review of Recent Advances in Superhydrophobic Surfaces and Their Applications in Drag Reduction and Heat Transfer

Zhang

Yang

et al. 2021

Nanomaterials

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Inspired by the superhydrophobic properties of some plants and animals with special structures, such as self-cleaning, water repellent, and drag reduction, the research on the basic theory and practical applications of superhydrophobic surfaces is increasing. In this paper, the characteristics of superhydrophobic surfaces and the preparation methods of superhydrophobic surfaces are briefly reviewed. The mechanisms of drag reduction on superhydrophobic surfaces and the effects of parameters such as flow rate, fluid viscosity, wettability, and surface morphology on drag reduction are discussed, as well as the applications of superhydrophobic surfaces in boiling heat transfer and condensation heat transfer. Finally, the limitations of adapting superhydrophobic surfaces to industrial applications are discussed. The possibility of applying superhydrophobic surfaces to highly viscous fluids for heat transfer to reduce flow resistance and improve heat transfer efficiency is introduced as a topic for further research in the future.

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“…integrated etching into a multistep process to create hierarchical micro–nanostructures on an aluminum tube ( Figure ), which was 440 mm long with an outer diameter of 25 mm and a thickness of 2 mm. [ 68 ] An uneven microstructure with a 1–10 µm scale was formed on the aluminum tube via HCl etching. This was followed by DI water oxidation to form a layer of nanostructure on the top.…”

Section: Superhydrophobic Surfacesmentioning

confidence: 99%

Implementing Superhydrophobic Surfaces within Various Condensation Environments: A Review

Singh

Zhang

Stafford

et al. 2020

Adv Materials Inter

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Steam condensation is omnipresent, and inevitable in many industrial processes. A classic example is seen within condensers that are used to liquify various gasses. In consequence, water‐vapor is eventually deposited upon the exterior of heat pipes that passively cool the gas to form a thin film of liquid. This macroscopic film is responsible for the degradation of heat transfer efficiencies. Liquid repellent surfaces can microscopically manipulate the hydrodynamics of formulating condensate to transition toward dropwise/jumping‐droplet condensation. This effect will save operating and maintenance costs of steam condensers within power‐plants, subsequently reducing emissions, operating power, and fuel consumption. However, the challenges associated with the stabilization of dropwise/jumping‐droplet condensation, especially at large subcooling temperatures and high supersaturation ratios, have prohibited the use of liquid repellent surfaces. This review aims to discuss recent improvements and understanding of dropwise/jumping‐droplet condensation surfaces on superhydrophobic surfaces. Numerous examples shall be included, showing experimental and numerical studies of various innovative properties of superhydrophobic structures. In addition, various fabrication techniques of superhydrophobic surfaces that are applicable within industrial systems are discussed. These topics are consolidated to provide guidelines for future research into dropwise/jumping‐droplet condensation on liquid repellent surfaces.

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Experimental study of condensation heat transfer on a horizontal aluminum tube with superhydrophobic characteristic

Cited by 22 publications

References 22 publications

Effect of Surface Structure Complexity on Interfacial Droplet Behavior of Superhydrophobic Titanium Surfaces for Robust Dropwise Condensation

Effect of Surface Structure Complexity on Interfacial Droplet Behavior of Superhydrophobic Titanium Surfaces for Robust Dropwise Condensation

A Review of Recent Advances in Superhydrophobic Surfaces and Their Applications in Drag Reduction and Heat Transfer

Implementing Superhydrophobic Surfaces within Various Condensation Environments: A Review

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