Dynamics of Microscale Liquid Propagation in Micropillar Arrays

Alhosani, Mohamed H.; Zhang, Tiejun

doi:10.1021/acs.langmuir.7b01090

Cited by 19 publications

(27 citation statements)

References 22 publications

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“…The contact angle, θ CA , is an important parameter in the capillary flow [106]. Therefore, we measured θ CA as a function of temperature for both untreated and treated surfaces.…”

Section: Resultsmentioning

confidence: 99%

Spreading and Drying Dynamics of Water Drop on Hot Surface of Superwicking Ti-6Al-4V Alloy Material Fabricated by Femtosecond Laser

Fang

Zhang

et al. 2021

Nanomaterials

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A superwicking Ti-6Al-4V alloy material with a hierarchical capillary surface structure was fabricated using femtosecond laser. The basic capillary surface structure is an array of micropillars/microholes. For enhancing its capillary action, the surface of the micropillars/microholes is additionally structured by regular fine microgrooves using a technique of laser-induced periodic surface structures (LIPSS), providing an extremely strong capillary action in a temperature range between 23 °C and 80 °C. Due to strong capillary action, a water drop quickly spreads in the wicking surface structure and forms a thin film over a large surface area, resulting in fast evaporation. The maximum water flow velocity after the acceleration stage is found to be 225–250 mm/s. In contrast to other metallic materials with surface capillarity produced by laser processing, the wicking performance of which quickly degrades with time, the wicking functionality of the material created here is long-lasting. Strong and long-lasting wicking properties make the created material suitable for a large variety of practical applications based on liquid-vapor phase change. Potential significant energy savings in air-conditioning and cooling data centers due to application of the material created here can contribute to mitigation of global warming.

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“…The contact angle, θ CA , is an important parameter in the capillary flow [106]. Therefore, we measured θ CA as a function of temperature for both untreated and treated surfaces.…”

Section: Resultsmentioning

confidence: 99%

Spreading and Drying Dynamics of Water Drop on Hot Surface of Superwicking Ti-6Al-4V Alloy Material Fabricated by Femtosecond Laser

Fang

Zhang

et al. 2021

Nanomaterials

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“…We observed that the large mesh surface has the highest liquid propagation speed of 45 mm s −1 , which is around 1.8 times larger than the micropillar surface in our previous work. [ 45 ] We also evaluated their dryout heat fluxes, as shown in Figure 6c. It can be found that the large mesh surface has the best performance with a dryout heat flux of 26.3 W cm −2 , ten times larger than the optimized micropillar surface ( d = 42, p = 90, and h = 100 μm) in the study by Horner et al [ 46 ] Dividing the heat flux by water latent heat, we converted the dryout heat flux into the limit of vapor flux for vapor generation applications (see Figure 6c).…”

Section: Resultsmentioning

confidence: 99%

Enhanced Liquid Propagation and Wicking Along Nanostructured Porous Surfaces

Alhosani

Alketbi

et al. 2021

Adv Eng Mater

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The crucial role of capillary pumping has motivated recent innovations in porous wicking materials for many energy and environment applications. Herein, the wick‐based liquid propagation along with a porous surface, including both macroscopic water transport behavior and microscopic wicking dynamics, with a group of nanostructured porous surfaces, is investigated. These hybrid wicking surfaces are fabricated in a scalable way by bonding copper micromeshes on flat surfaces and chemical etching. These nanostructured porous surfaces exhibit outstanding wickability by simultaneously improving surface hydrophilicity and minimizing viscous dissipation of water flow. Notably, the as‐fabricated surfaces also have good thermal conductivity and high solar absorptance, which are desired properties for various solar thermal applications. To directly observe water propagation processes, infrared thermal imaging in locating the propagation front and evaluating water film thickness along the propagation direction is also demonstrated. The dynamic water vapor meniscus in a representative pore unit is captured and characterized through environmental scanning electron microscopy. A capillary pressure model and permeability model to predict the liquid propagation and wicking characteristics is then developed, resulting in good agreement with experimental results for a large variety of nanostructured porous surfaces.

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“…While substrates must be good thermal insulators with excellent water transporting properties. Therefore to be effective vapor generator, absorbers must have the following important properties: 1) absorb light across a wide range of wavelengths (380 to 2500 nm) and have a high-efficiency light-to-heat conversion; 2) capable of confining the generated heat to the evaporative surface for maximum evaporation and minimizing heat losses to the environment; and 3) the porous substrate should have good interface wettability and a well-designed structure for achieving continuous and efficient water transport form the underlying saline water reservoir to the upper evaporative surface [282,284]. However, achieving optimal outcomes for all these properties is challenging.…”

Section: Floating Solar Absorbers For Water Vapor Generationmentioning

confidence: 99%

Solar Thermal Energy Stills for Desalination: A Review of Designs, Operational Parameters and Material Advances

Chamsa-ard¹,

Fawcett²,

Fung³

et al. 2020

JEPT

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The demand for high-quality freshwater is increasing due to global population growth, intensifying agricultural practices and expanding industrial development. Additionally, many global regions have low levels of rainfall which makes them arid and incapable of supporting large human populations or agriculture. Currently, large quantities of fossil fuels are used to generate the power needed to drive energy intensive desalination processes that deliver high-quality freshwater to many of these regions. However, the use of fossil fuels has led to high greenhouse gas emissions, environmental degradation and global warming. Solar-thermal desalination is a low-cost, sustainable and eco-friendly strategy for producing high-quality freshwater without using energy derived from fossil fuels. However, in spite of recent developments to advance solar-thermal desalination, the most effective strategies for achieving higher performance levels still remains elusive. To tackle this problem, the present article reviews several solar-thermal still configurations, including materials, system design parameters, influencing factors and operational parameters. Moreover, recent material advances in plasmonic nanoparticle-based volumetric systems, nanomaterial enhanced phase change materials and interfacial solar evaporators are discussed. These new material advances can have the potential to significantly improve the conversion of light-to-heat, enhance vapor generation and promote greater water production rates.

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Dynamics of Microscale Liquid Propagation in Micropillar Arrays

Cited by 19 publications

References 22 publications

Spreading and Drying Dynamics of Water Drop on Hot Surface of Superwicking Ti-6Al-4V Alloy Material Fabricated by Femtosecond Laser

Spreading and Drying Dynamics of Water Drop on Hot Surface of Superwicking Ti-6Al-4V Alloy Material Fabricated by Femtosecond Laser

Enhanced Liquid Propagation and Wicking Along Nanostructured Porous Surfaces

Solar Thermal Energy Stills for Desalination: A Review of Designs, Operational Parameters and Material Advances

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