Investigating the combined effect of square microgrooves and CNT coating on condensation heat transfer

Kumar, G. Udaya; Krishnan, D. Venkata; Suresh, S.; Thansekhar, M.R.; Prasanna, R. Varun; Jubal, M.

doi:10.1016/j.apsusc.2018.10.245

Cited by 19 publications

(7 citation statements)

References 36 publications

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“…For example, Peng et al [18] fabricated hierarchical microgrooved superhydrophobic surfaces by mechanical broaching and chemical etching, achieving an increase in heat flux of 90% compared to the flat surface for ΔΤ < 5 Κ, by inducing jumping droplets in two different length scales. [18] In the same path, Kumar et al [19] investigated the combined effect of squared-grooved surfaces with a CNT coating in heat transfer coefficient. They measured heat transfer in grooved surfaces, with and without the CNT coating, and showed that the coated surfaces achieved a heat transfer coefficient of 61.11 kW m −2 K −1 for subcooling of 1 K. They also found that as the aspect ratio of the grooves increases, the higher the heat transfer coefficient is, due to the increased surface area of condensation.…”

Section: Introductionmentioning

confidence: 99%

Topography Optimization for Sustainable Dropwise Condensation: The Critical Role of Correlation Length

Sarkiris,

Constantoudis,

Ellinas

et al. 2023

Adv Funct Materials

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An effective pathway to enhance the heat transfer process is to induce the formation of highly mobile condensate droplets, employing micro‐nanoengineered superhydrophobic surfaces. However, the design of the topography of these surfaces for sustained high performance constitutes a significant scientific and technological challenge. Herein, the critical role of the correlation length of topography is demonstrated as an important factor when designing superhydrophobic surfaces for heat transfer applications. Specifically, it is shown that a) a high correlation length value corresponds to increased space between surface structures and higher lateral distances between nucleating droplets, which results in lower droplet departure diameter and significantly delayed flooding of the surface and b) correlation length has to surpass a critical value for dropwise condensation (DWC) to be sustained in hierarchical structured surfaces, when the droplets are growing in a partial Cassie state. Following this rationale, droplets are categorized in three different energy and wetting states (Wenzel droplets, Cassie droplets of low kinetic energy and high energy jumping droplets), depending on the correlation length of the topography. Heat transfer experiments demonstrate an increase of 126% in the heat transfer coefficient (HTC) of surfaces exhibiting the maximum correlation length when compared to the flat hydrophobic surface.

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Section: Introductionmentioning

confidence: 99%

Topography Optimization for Sustainable Dropwise Condensation: The Critical Role of Correlation Length

Sarkiris,

Constantoudis,

Ellinas

et al. 2023

Adv Funct Materials

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“…Their results also mentioned that the optimal parameter of the nanostructure depended on whether a droplet could bounce off the surface. Udaya Kumar et al 6 designed a composite structure composed of square grooves and CNT coating. The grooving process resulted in an increased condensation area and decreased adhesion force.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Vapor Condensation on a Hierarchical Microstructured Surface with a Phase-Change LB Method

Jin,

Mu,

et al. 2023

Ind. Eng. Chem. Res.

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“…Plenty of studies have revealed the condensation mechanisms and characteristics on nanosurfaces. − The droplet condensation on the surface can be classified into dropwise condensation and filmwise condensation. Due to the smaller thermal resistance and disturbance by the dropping of droplets, dropwise condensation has a superior heat transfer capability than filmwise condensation .…”

Section: Introductionmentioning

confidence: 99%

“…Due to the smaller thermal resistance and disturbance by the dropping of droplets, dropwise condensation has a superior heat transfer capability than filmwise condensation . Many enhancement methods, including fabricating nanostructures on surfaces, − coating surfaces, − and changing materials near surfaces, , are proposed to improve condensation heat transfer. For example, the dropwise condensation heat transfer coefficient was improved by 89% (in comparison with flat samples) when a type of copper-based ultrathin nickel nanocone film was experimentally fabricated by Zhao et al .…”

Section: Introductionmentioning

confidence: 99%

Flow Condensation Heat Transfer Characteristics of Nanochannels with Nanopillars: A Molecular Dynamics Study

Wang

Sun

Cheng³

2021

Langmuir

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Flow condensation in nanochannels is a high-efficiency method to deal with increasingly higher heat flux from micro/nanoelectronic devices. Here, we study the flow condensation heat transfer characteristics of nanochannels with different nanopillar crosssectional areas and heights using molecular dynamics simulation. Results show that two phases containing vapor in the middle of the channel and liquid near walls can be distinguished by obvious interfaces when the fluid is at a stable state. The condensation performance can be promoted by adding nanopillars. With the increase in nanopillar crosssectional areas or heights, the time that the fluid spends to reach stability will be put off, while the condensation performance enhances. Different from the small enhancement of nanopillar cross-sectional areas, the condensation heat transfer performance improves significantly at a higher nanopillar height, which increases the heat transfer rates by 11.6 and 35.8% when heights are 6a and 8a, respectively. The preeminent condensation heat transfer performance is ascribed to the fact that nanopillars with a higher height disturb the vapor−liquid interface and vapor region, which not only allows vapor atoms with strong Brownian motion to collide with nanopillar atoms directly but also increases deviations of vapor−liquid potential energy to facilitate condensation heat transfer in nanochannels.

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Investigating the combined effect of square microgrooves and CNT coating on condensation heat transfer

Cited by 19 publications

References 36 publications

Topography Optimization for Sustainable Dropwise Condensation: The Critical Role of Correlation Length

Topography Optimization for Sustainable Dropwise Condensation: The Critical Role of Correlation Length

Numerical Investigation of Vapor Condensation on a Hierarchical Microstructured Surface with a Phase-Change LB Method

Flow Condensation Heat Transfer Characteristics of Nanochannels with Nanopillars: A Molecular Dynamics Study

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