Pool Boiling Performance Comparison of Smooth and Sintered Copper Surfaces with and Without Carbon Nanotubes

McHale, John P.; Garimella, Suresh V.; Fisher, Timothy S.; Powell, Glen A.

doi:10.1080/15567265.2011.575918

Cited by 66 publications

(29 citation statements)

References 35 publications

(36 reference statements)

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“…While it is difficult to ascertain the exact cause of this structural damage to the central region of the wick surface post-testing, it is believed to have occurred at or near the dryout heat flux test point. This theory is supported by prior capillary-fed [37] and pool boiling [24] investigations in which CNT-coated samples were evaluated below the dryout heat flux, and at least partial CNT coverage was observed to be retained post-testing. In future studies, thermal cycling tests at moderate heat fluxes will be performed to evaluate structural degradation of these wick samples over time.…”

Section: Surface Morphology After Thermal Testingsupporting

confidence: 50%

“…Comparison of thermal resistances of the four samples (Fig. 8) The propensity of CNTs to initiate bubble nucleation at lower surface superheats was previously reported in pool boiling studies [22,24] as well as for CNT-enhanced wicks [16,26]. It is notable that this phenomenon is independent of wick thickness for millimeter and sub-millimeter thick wicks.…”

Section: Effect Of Varying Cnt Copper Coating Thickness On Overall Thmentioning

confidence: 71%

“…While these two studies utilized highly wetting dielectric fluids, water is the preferred working fluid for use in vapor chambers for electronics cooling applications. Pool boiling experiments on hybrid sintered/CNT surface [24] employing deionized water as the working fluid revealed a significant reduction in boiling incipience superheat compared to a plain flat copper surface.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Metal functionalization of carbon nanotubes for enhanced sintered powder wicks

Kousalya

Weibel

Garimella

et al. 2013

International Journal of Heat and Mass Transfer

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Phase change cooling schemes involving passive heat spreading devices, such as heat pipes and vapor chambers, are widely adopted for thermal management of high heat-flux technologies. In this study, carbon nanotubes (CNTs) are fabricated on a 200 μm thick sintered copper powder wick layer using a microwave plasma enhanced chemical vapor deposition technique. A physical vapor deposition process is used to coat the CNTs with a varying thickness of copper to promote surface wetting with the working fluid, water. Thermal performance of the bare sintered copper powder sample (without CNTs) and the copper-functionalized CNT-coated sintered copper powder wick samples is compared using an experimental facility that simulates the capillary fluid feeding conditions of a vapor chamber. A notable reduction in the boiling incipience superheat is observed for the nanostructured samples. Additionally, nanostructured samples having a thicker copper coating provided a considerable increase in dryout heat flux, supporting heat fluxes up to 457 W/cm 2 from a 5 mm × 5 mm heat input area, while maintaining lower surface superheat temperatures compared to a bare sintered powder sample; this enhancement is attributed primarily to the improved surface wettability. Dynamic contact angle measurements are conducted to quantitatively compare the surface wetting trends for varying copper coating thicknesses and confirm the increase in hydrophilicity with increasing coating thickness.

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Section: Surface Morphology After Thermal Testingsupporting

confidence: 50%

Section: Effect Of Varying Cnt Copper Coating Thickness On Overall Thmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Metal functionalization of carbon nanotubes for enhanced sintered powder wicks

Kousalya

Weibel

Garimella

et al. 2013

International Journal of Heat and Mass Transfer

Self Cite

View full text Add to dashboard Cite

show abstract

“…Water has a comparatively higher surface tension, and therefore tends to form stable nucleation sites at lower superheats than highly wetting fluids. This translates into measured incipience superheats of ~10 °C from smooth surfaces [78] and less than 1.5 °C for pool boiling of water from sintered porous surfaces [19,80].…”

Section: Incipience Of Boiling Under Capillary-fed Conditionsmentioning

confidence: 99%

“…Nanostructures have been reported to improve differing aspects of the boiling process (e.g., incipience, nucleation boiling, and critical heat flux) via CNT-coating of silicon [211][212][213] and copper substrates [80,213], and copper nanowire [214][215][216] and silicon nanowire [215][216][217] surface coatings.…”

Section: Nanostructured Capillary Wicks For Vapor Chamber Applicationsmentioning

confidence: 99%

Recent Advances in Vapor Chamber Transport Characterization for High-Heat-Flux Applications

Weibel

Garimella

2013

Advances in Heat Transfer

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Owing to their high reliability, simplicity of manufacture, passive operation, and effective heat transport, flat heat pipes and vapor chambers are used extensively in the thermal management of electronic devices. The need for concurrent size, weight, and performance improvements in high-performance electronics systems, without resort to active liquid-cooling strategies, demands passive heat spreading technologies that can dissipate extremely high heat fluxes from small hot spots. In response to these daunting application-driven trends, a number of recent investigations have focused on the design, characterization, and fabrication of ultra-thin vapor chambers for proximate heat spreading away from these hot spots. The predominant transport mechanisms and operational limits have been found to be different under these conditions relative to conventional low-power heat pipes. Noteworthy advances in the fundamental understanding of evaporation and boiling from porous microstructures fed by capillary action, and improvements in vapor chamber characterization, modeling, design, and fabrication techniques are reviewed. Characterization of evaporation and boiling from idealized and realistic wick structures, observation of vapor formation regimes as a function of operating conditions, assessment of fluid dryout limitations, design of novel multi-scale and nanostructured wicks for enhanced transport, and incorporation of these high heat flux transport phenomena into device-level models are discussed. These recent developments have successfully extended the maximum operating heat flux limits of vapor chambers.2

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Experimental Investigation on Flow Boiling Heat Transfer Characteristics of Water Inside Micro/Nanostructured-Coated Minichannel

Gupta,

Misra

2023

Int J Thermophys

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Pool Boiling Performance Comparison of Smooth and Sintered Copper Surfaces with and Without Carbon Nanotubes

Cited by 66 publications

References 35 publications

Metal functionalization of carbon nanotubes for enhanced sintered powder wicks

Metal functionalization of carbon nanotubes for enhanced sintered powder wicks

Recent Advances in Vapor Chamber Transport Characterization for High-Heat-Flux Applications

Experimental Investigation on Flow Boiling Heat Transfer Characteristics of Water Inside Micro/Nanostructured-Coated Minichannel

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