Monoporous micropillar wick structures, II-optimization &amp; theoretical limits

Horner, David A.; Ravi, Saitej; Moghaddam, Saeed

doi:10.1016/j.applthermaleng.2014.04.055

Cited by 27 publications

(33 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, a thicker liquid allows a higher liquid mass flow rate, which contributes to a higher q dry-out . This trend agrees with previous modeling based on the Darcy's equation and experimental observations 14,15 . However, increasing the height of the pillars increases the superheat at the solid surface.…”

Section: Resultssupporting

confidence: 93%

Prediction and Characterization of Dry-out Heat Flux in Micropillar Wick Structures

Zhu

Antao

et al. 2016

Langmuir

View full text Add to dashboard Cite

Thin-film evaporation in wick structures for cooling high-performance electronic devices is attractive because it harnesses the latent heat of vaporization and does not require external pumping. However, optimizing the wick structures to increase the dry-out heat flux is challenging due to the complexities in modeling the liquid-vapor interface and the flow through the wick structures. In this work, we developed a model for thin-film evaporation from micropillar array wick structures and validated the model with experiments. The model numerically simulates liquid velocity, pressure, and meniscus curvature along the wicking direction by conservation of mass, momentum, and energy based on a finite volume approach. Specifically, the three-dimensional meniscus shape, which varies along the wicking direction with the local liquid pressure, is accurately captured by a force balance using the Young-Laplace equation. The dry-out condition is determined when the minimum contact angle on the pillar surface reaches the receding contact angle as the applied heat flux increases. With this model, we predict the dry-out heat flux on various micropillar structure geometries (diameter, pitch, and height) in the length scale range of 1-100 μm and discuss the optimal geometries to maximize the dry-out heat flux. We also performed detailed experiments to validate the model predictions, which show good agreement. This work provides insights into the role of surface structures in thin-film evaporation and offers important design guidelines for enhanced thermal management of high-performance electronic devices.

show abstract

Section: Resultssupporting

confidence: 93%

Prediction and Characterization of Dry-out Heat Flux in Micropillar Wick Structures

Zhu

Antao

et al. 2016

Langmuir

View full text Add to dashboard Cite

show abstract

“…) was less profound for taller micropillars, which also led to a higher dryout heat flux. This trend agreed with previous theoretical and experimental studies [80,81].…”

Section: •K)supporting

confidence: 93%

“…Hornor et al [81] Performance of uniform micropillar evaporators experimentally tested in the literatures are summarized in Table 3.…”

Section: Squarely Packed Cylindrical Micropillar Arraysmentioning

confidence: 99%

Modeling, optimization and thermal characterization of micropillar evaporator based high performance silicon vapor chamber

Wei¹

View full text Add to dashboard Cite

show abstract

“…[ 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). Given the solar absorptance measured in Figure 1f, the vapor flux generated under 1 Sun is only 1.49 kg (m 2 h) −1 , whereas the vapor generation limit of the large mesh surface is 418.94 kg/(m 2 h) −1 .…”

Section: Resultsmentioning

confidence: 99%

Enhanced Liquid Propagation and Wicking Along Nanostructured Porous Surfaces

Alhosani

Alketbi

et al. 2021

Adv Eng Mater

View full text Add to dashboard Cite

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.

show abstract

Monoporous micropillar wick structures, II-optimization & theoretical limits

Cited by 27 publications

References 8 publications

Prediction and Characterization of Dry-out Heat Flux in Micropillar Wick Structures

Prediction and Characterization of Dry-out Heat Flux in Micropillar Wick Structures

Modeling, optimization and thermal characterization of micropillar evaporator based high performance silicon vapor chamber

Enhanced Liquid Propagation and Wicking Along Nanostructured Porous Surfaces

Contact Info

Product

Resources

About