The permeability of screen wicks.

Kozai, Hiroaki; Imura, Hidefumi; Ikeda, Yûji

doi:10.1299/kikaib.56.161

Cited by 6 publications

(7 citation statements)

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“…The permeability of a wick can be found by forcing liquid through a representative sample at a known flow rate and measuring the resultant pressure drop, either in a linear [131] or radial orientation [132]. Kozai et al [131] investigated the permeability of metal screen wicks as functions of the number of layers, mesh size, and screen…”

Section: Empirical Characterizationmentioning

confidence: 99%

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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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Section: Empirical Characterizationmentioning

confidence: 99%

“…Kozai et al [131] investigated the permeability of metal screen wicks as functions of the number of layers, mesh size, and screen…”

Section: Empirical Characterizationmentioning

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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“…This dryout prediction was based solely on the pressure drop in the heat pipe and can be readily and accurately predicted when the capillary pore radius and permeability of the wick material are well defined [2][3][4]. Wang and Peterson [5] developed a two-dimensional analytical model of a square sintered powder evaporator region and calculated the maximum heat flux capacity based on the pressure drop through the porous layer.…”

Section: Introductionmentioning

confidence: 99%

Characterization of evaporation and boiling from sintered powder wicks fed by capillary action

Weibel

Garimella

North

2010

International Journal of Heat and Mass Transfer

244

124

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a b s t r a c tThe thermal resistance to heat transfer into the evaporator section of heat pipes and vapor chambers plays a dominant role in governing their overall performance. It is therefore critical to quantify this resistance for commonly used sintered copper powder wick surfaces, both under evaporation and boiling conditions. The objective of the current study is to measure the dependence of thermal resistance on the thickness and particle size of such surfaces. A novel test facility is developed which feeds the test fluid, water, to the wick by capillary action. This simulates the feeding mechanism within an actual heat pipe, referred to as wicked evaporation or boiling. Experiments with multiple samples, with thicknesses ranging from 600 to 1200 lm and particle sizes from 45 to 355 lm, demonstrate that for a given wick thickness, an optimum particle size exists which maximizes the boiling heat transfer coefficient. The tests also show that monoporous sintered wicks are able to support local heat fluxes of greater than 500 W cm À2 without the occurrence of dryout. Additionally, in situ visualization of the wick surfaces during evaporation and boiling allows the thermal performance to be correlated with the observed regimes. It is seen that nucleate boiling from the wick substrate leads to substantially increased performance as compared to evaporation from the liquid free surface at the top of the wick layer. The sharp reduction in overall thermal resistance upon transition to a boiling regime is primarily attributable to the conductive resistance through the saturated wick material being bypassed.

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“…For example, Jaubourg (1988) andTillie (1988) mentioned the porosity, the structure and the texture of screens as determining the resistance to wind flow-through. Kozai et al(1991) have made an attempt to define the permeability of screen wicks by experimental and analytic techniques. Depending on the application for which the screen is intended, the authors studied particular parameters.…”

Section: Properties Of Screensmentioning

confidence: 99%

“…Kozai (1991) has defined mathematical equations for calculation of the porosity of screens determined by a model of the screen geometry based on microscopic observations. 2.1.1.5 Permeability.…”

Section: Geometric Parametersmentioning

confidence: 99%

Thermal Characteristics of Screenhouse Configurations in a West-African Tropical Climate

Desmarais¹,

Raghavan²

1997

Acta Hortic.

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The permeability of screen wicks.

Cited by 6 publications

References 0 publications

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

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

Characterization of evaporation and boiling from sintered powder wicks fed by capillary action

Thermal Characteristics of Screenhouse Configurations in a West-African Tropical Climate

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