Development and Experimental Validation of a Micro/Nano Thermal Ground Plane

Bock, Hannes; Chauhan, Shakti; Chamarthy, Pramod; Eastman, Chris; Weaver, Stanton; Whalen, Bryan; Deng, Tao; Russ, Boris; Gerner, Frank M.; Johnson, Douglas; Courson, David L.; Leland, Quinn; Yerkes, Kirk L.

doi:10.1115/ajtec2011-44646

Cited by 5 publications

(9 citation statements)

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“…A 30 mm × 30 mm × 3 mm vapor chamber thermal ground plane (Figure 29b) was recently designed, fabricated, and tested in an effort led by researchers at GE Global Research [175,176]. Device performance is extremely sensitive to small variations in the amount of initial fluid charge at this form factor; over-filling floods the condenser and under-filling may lead to premature dryout.…”

Section: Micro/nanostructured Thermal Ground Plane (Tgp)mentioning

confidence: 99%

“…In order to ensure dissipation of the desired heat load against an exerted body force 10 times normal gravity, it was found that the properties of a sintered powder wick with 75 μm particle diameters [136,140] would avoid the capillary limitation [176]. The effective thermal conductivity of 3 prototype vapor chambers was measured as a function of the gravitational body force by mounting on a centrifuge spin table.…”

Section: Micro/nanostructured Thermal Ground Plane (Tgp)mentioning

confidence: 99%

“…The thermal resistance change was negligible due to the minimal additional vapor pressure drop imposed at the maximum gravitational loading. The same prototype devices were tested as a function of input heat flux, and under certain operating conditions exceeded the effective thermal conductivity of copper at an adverse body force 10 times gravity [176]. …”

Section: Micro/nanostructured Thermal Ground Plane (Tgp)mentioning

confidence: 99%

“…To ensure device performance under adverse gravitational forces, de Bock et al [176] developed device thermal performance and capillary limitation models based on an effective thermal resistance network and simplified expressions for liquid/vapor-phase pressure drop, respectively. In order to ensure dissipation of the desired heat load against an exerted body force 10 times normal gravity, it was found that the properties of a sintered powder wick with 75 μm particle diameters [136,140] would avoid the capillary limitation [176].…”

Section: Micro/nanostructured Thermal Ground Plane (Tgp)mentioning

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: Micro/nanostructured Thermal Ground Plane (Tgp)mentioning

confidence: 99%

Section: Micro/nanostructured Thermal Ground Plane (Tgp)mentioning

confidence: 99%

Section: Micro/nanostructured Thermal Ground Plane (Tgp)mentioning

confidence: 99%

Section: Micro/nanostructured Thermal Ground Plane (Tgp)mentioning

confidence: 99%

See 2 more Smart Citations

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

Weibel

Garimella

2013

Advances in Heat Transfer

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“…A total of 15 samples were tested three times to provide sufficient statistical data. Variation in measured effective thermal conductivity is attributed to local porosity variation within the sample [23]. As shown in Figure 5, the laser flash method gives an effective thermal conductivity of about 170 W/m.K for the sintered copper wick samples when the porosity about 0.5 and this is gives 4% error -related to the uncertainty of the wick porosity-when comparing with k wick =163.2 W/m.K from Maxwell's equation.…”

Section: Theortical Modelmentioning

confidence: 96%

Thermal-Fluid Modeling For High Thermal Conductivity Heat Pipe Thermal Ground Planes

Ababneh¹,

Gerner²,

Chamarthy³

et al. 2014

Journal of Thermophysics and Heat Transfer

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The thermal ground plane (TGP) is an advanced planar heat pipe designed for cooling microelectronics in high gravitational fields. A thermal resistance model is developed to predict the thermal performance of the TGP, including the effects of the presence of non-condensable gases (NCGs). Viscous laminar flow pressure losses are predicted to determine the maximum heat load when the capillary limit is reached. This paper shows that the axial effective thermal conductivity of the TGP decreases when the substrate and/or wick are thicker and/or with the presence of NCGs. Moreover, it was demonstrated that the thermal-fluid model may be utilized to optimize the performance of the TGP by estimating the limits of wick thickness and vapor space thickness for a recognized internal volume of the TGP. The wick porosity plays a significant role on maximum heat transport capability. A large adverse gravitational field strongly decreases the maximum heat transport capability of the TGP. Axial effective thermal conductivity is mostly unaffected by the gravitational field. The maximum length of the TGP before reaching the capillary limit is inversely proportional to input power.

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Thermal performance of a flat polymer heat pipe heat spreader under high acceleration

Oshman

Liew

et al. 2012

J. Micromech. Microeng.

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This paper presents the fabrication and application of a micro-scale hybrid wicking structure in a flat polymer-based heat pipe heat spreader, which improves the heat transfer performance under high adverse acceleration. The hybrid wicking structure which enhances evaporation and condensation heat transfer under adverse acceleration consists of 100 μm high, 200 μm wide square electroplated copper micro-pillars with 31 μm wide grooves for liquid flow and a woven copper mesh with 51 μm diameter wires and 76 μm spacing. The interior vapor chamber of the heat pipe heat spreader was 30 × 30 × 1.0 mm 3 . The casing of the heat spreader is a 100 μm thick liquid crystal polymer which contains a two-dimensional array of copper-filled vias to reduce the overall thermal resistance. The device performance was assessed under 0-10 g acceleration with 20, 30 and 40 W power input on an evaporator area of 8 × 8 mm 2 . The effective thermal conductivity of the device was determined to range from 1653 W (m K) −1 at 0 g to 541 W (m K) −1 at 10 g using finite element analysis in conjunction with a copper reference sample. In all cases, the effective thermal conductivity remained higher than that of the copper reference sample. This work illustrates the possibility of fabricating flexible, polymer-based heat pipe heat spreaders compatible with standardized printed circuit board technologies that are capable of efficiently extracting heat at relatively high dynamic acceleration levels.

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Development and Experimental Validation of a Micro/Nano Thermal Ground Plane

Cited by 5 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

Thermal-Fluid Modeling For High Thermal Conductivity Heat Pipe Thermal Ground Planes

Thermal performance of a flat polymer heat pipe heat spreader under high acceleration

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