Recent Advances in the Modeling and Applications of Nonconventional Heat Pipes

Garimella, Suresh V.; Sobhan, C. B.

doi:10.1016/s0065-2717(01)80022-8

Cited by 29 publications

(15 citation statements)

References 120 publications

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“…Modeling of vapor chambers is complicated by the coupled heat, mass, and momentum transport mechanisms prevalent in the device, such as evaporation and condensation at the liquidvapor interfaces; however, a number of modeling approaches have been developed that approximate transport with various levels of fidelity. Garimella and Sobhan [8] and Faghri [9] provided reviews of the modeling approaches for a variety of heat pipe device types. Modeling of the transport in thin vapor chambers (i.e., flat heat pipes) is briefly reviewed first, to provide a context for the state-of-the-art advances in modeling approaches discussed in detail in Section 3.2 and Section 3.3.…”

Section: Device-level Modeling Testing and Design For High Heat Flumentioning

confidence: 99%

“…Examples including variable conductance gas-loaded heat pipes for constant temperature control, capillary pumped loops for wickless transport over long working distances, rotating heat pipes in which liquid return occurs by centrifugal force, micro heat pipes, thermal diodes, oscillating heat pipes, and others are described in detail in [1][2][3][4]. Recent reviews summarize research on emerging heat pipe applications [5,6], novel working fluid developments [7], advances in modeling approaches [8,9], and performance of archetypal device geometries, such as loop heat pipes [10,11], micro heat pipes [12], and oscillating heat pipes [13]. A comprehensive summary of all such device types, applications, and analysis methodologies is outside the scope of the current review; instead, the focus is on the burgeoning interest and developments in heat pipes targeted at spreading of very high heat fluxes in ultra-thin form factors, as discussed in the following section…”

Section: Introductionmentioning

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: Device-level Modeling Testing and Design For High Heat Flumentioning

confidence: 99%

Section: Introductionmentioning

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 pressure drop is related to the saturation temperature drop by applying the Clapeyron equation and ideal gas law. By this approach, an effective thermal conductivity [4] is defined for a onedimensional lateral resistance along the effective length of the vapor 2 2…”

Section: A Thermal Resistance Network Modelmentioning

confidence: 99%

“…Many analytical and numerical modeling approaches have been developed to study the performance of heat pipes at varying levels of spatial and temporal fidelity, as reviewed for various types of heat pipes by Garimella and Sobhan [2] and Faghri [3]. A simplified thermal resistance network-based analysis of heat pipe performance by Prasher [4] accurately predicted thermal resistance even under the nonuniform experimental heating conditions investigated by Chang et al [5].…”

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confidence: 99%

Performance-Governing Transport Mechanisms for Heat Pipes at Ultrathin Form Factors

Yadavalli

Weibel

Garimella

2015

IEEE Trans. Compon., Packag. Manufact. Technol.

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Abstract-Heat pipes and vapor chamber heat spreaders offer a potential solution to the increasing thermal management challenges in thin-form-factor mobile computing platforms, where efficient spreading is required to simultaneously prevent overheating of internal components and formation of hot regions on the device exterior surfaces. Heat pipe performance limitations unique to such ultra-thin form factors, and the key heat transfer mechanisms governing the performance, must be characterized. A thermal resistance network model and a detailed two-dimensional numerical model are used to analyze the performance of heat pipes under these conditions. A broad parametric study of geometries and heat inputs using the reduced-order model helps delineate the performance thresholds within which the effectiveness of a heat pipe is greater than a comparable solid heat spreader. A vapor-phase threshold unique to ultra-thin heat pipes operating at low power inputs is observed. At this threshold, the vapor-phase thermal resistance imposed by the saturation pressure/temperature gradient in the heat pipe causes a crossover in the thermal resistance relative to a solid heat spreader. The higher-fidelity numerical model is used to assess the accuracy of the resistance network model and to verify the validity and applicability of each assumption made regarding the transport mechanisms. Key heat transfer mechanisms not captured by the reduced-order thermal network models are identified. These include the effects of boundary conditions on the interface mass flux profile, convective effects on the vapor core temperature drop, and two-dimensional conduction on smearing of evaporation/condensation mass flux into the adiabatic section.

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“…The analysis of the operation and performance of heat pipes has received a lot of attention, and a comprehensive review is available in Garimella and Sobhan [49]. For the most part, attention has been focused on the study of either flat or round heat pipes, typically with single heat sources.…”

Section: Heat Pipesmentioning

confidence: 99%