Liquid Flow Analysis in Porous Media for Large Vapor Chamber With Multiple Heat Sources

Escobar, Sergio; Kumari, Niru; Shih, Rocky; Anthony, Sarah; Bash, Cullen

doi:10.1115/ipack2015-48770

Cited by 2 publications

(1 citation statement)

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“…The design of large flat plate heat pipes can be found in the literature [14,[25][26][27]. The production of large scale heat pipes is primarily limited by their wick fabrication process.…”

Section: Introductionmentioning

confidence: 99%

A novel ultra-large flat plate heat pipe manufactured by thermal spray

Feng

Gibbons

Marengo

et al. 2020

Applied Thermal Engineering

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An ultra-large flat plate copper heat pipe (180 x 180 mm 2) was constructed using a thermal spray technique, and it was then thermally characterized. A porous copper wick was fabricated by using a flame spray torch to deposit a mixture of copper and aluminum particles onto the target substrate. A stainless-steel wire mesh acts as a mask so that the coating deposited is in the form of an array of microstructures with channels between them. After spraying, the aluminum deposit is leached away by immersing the plate in a dilute NaOH solution to produce a porous structure. A second copper plate was placed on top of the coated surface, and their edges were vacuum brazed to form a sealed enclosure. The enclosed volume was evacuated and partially filled with water to form a heat pipe. The heat pipe was centrally heated from its bottom and cooled along its top outer edge. Three liquid filling ratios and six heat fluxes from 2.5 W/cm 2 to 15 W/cm 2 were investigated. A decreasing lateral thermal resistance for an increasing applied heat flux was noted for all filling ratios until central dry-out. Central dry-out corresponds to the point where the evaporation rate outpaces the wicking of the working fluid at the centre of the heat pipe. Dry-out of the central wick results in a large thermal resistance compared to the pre-dry-out condition. Delayed dry-out onset was noted for increasing working fluid filling ratios. In the pre-dry-out condition, a peak average radial thermal conductivity of 920 W/m K was noted for a 65% filling ratio, and 7.5 W/cm 2 applied heat flux. A model was generated to calculate dry-out of the thermally sprayed porous wick for a given filling ratio and applied heat flux. The present research represents two highly novel advances in heat pipe technology. The first is the development of a new innovative manufacturing technique for the generation of a porous wick structure within a heat pipe. This new manufacturing technique enables the production of large metal vapour chambers with complex 3D geometries. When applied in conjunction with copper compatible working fluids, this techniques facilitates the realization of skin thermal conductors. Second, the fabrication of an ultra-large flat plate heat pipe that is significantly larger than that previously reported in the literature is demonstrated.

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“…The design of large flat plate heat pipes can be found in the literature [14,[25][26][27]. The production of large scale heat pipes is primarily limited by their wick fabrication process.…”

Section: Introductionmentioning

confidence: 99%

A novel ultra-large flat plate heat pipe manufactured by thermal spray

Feng

Gibbons

Marengo

et al. 2020

Applied Thermal Engineering

View full text Add to dashboard Cite

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Experimental Development and Computational Optimization of Flat Heat Pipes for CubeSat Applications

Isaacs

Arias

Hengeveld

et al. 2017

Journal of Electronic Packaging

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Due to the compact and modular nature of CubeSats, thermal management has become a major bottleneck in system design and performance. In this study, we outline the development, initial testing, and modeling of a flat, conformable, lightweight, and efficient two-phase heat strap called FlexCool, currently being developed at Roccor. Using acetone as the working fluid, the heat strap has an average effective thermal conductivity of 2149 W/m K, which is approximately five times greater than the thermal conductivity of pure copper. Moreover, the heat strap has a total thickness of only 0.86 mm and is able to withstand internal vapor pressures as high as 930 kPa, demonstrating the suitability of the heat strap for orbital environments where pressure differences can be large. A reduced-order, closed-form theoretical model has been developed in order to predict the maximum heat load achieved by the heat strap for different design and operating parameters. The model is validated using experimental measurements and is used here in combination with a genetic algorithm to optimize the design of the heat strap with respect to maximizing heat transport capability.

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Liquid Flow Analysis in Porous Media for Large Vapor Chamber With Multiple Heat Sources

Cited by 2 publications

References 0 publications

A novel ultra-large flat plate heat pipe manufactured by thermal spray

A novel ultra-large flat plate heat pipe manufactured by thermal spray

Experimental Development and Computational Optimization of Flat Heat Pipes for CubeSat Applications

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