Approaching the limits of two-phase boiling heat transfer: High heat flux and low superheat

Palko, James W.; Zhang, Chi; Wilbur, Joshua D.; Dusseault, Tom J.; Asheghi, Mehdi; Goodson, Kenneth E.; Santiago, Juan G.

doi:10.1063/1.4938202

Cited by 53 publications

(38 citation statements)

References 27 publications

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“…It is also noted that the extreme hot-spot heat fluxes imposed in this work (q 00 f >1000 W cm −2 ) match very well with those projected for cooling next-generation microelectronics 50 . Moreover, the extreme heat fluxes complement those recently achieved via boiling in capillary-fed porous wicks 26,51,52 and jetimpingement boiling 53 .…”

Section: Onb Wmentioning

confidence: 86%

“…The temperature and wall heat flux are rarely measured independently. Most commonly, the surface heat flux is estimated based on spatiotemporal temperature measurements 10,[22][23][24][25] with the assistance of numerical modeling to account for conjugate effects 26,27 . Moreover, the fluid temperature is typically measured at large distances from the three-phase-interface (e.g., at the inlet and outlet of a microchannel device) 18 ; or alternatively, it is calculated via numerical methods using an estimated surface heat flux 21 .…”

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confidence: 99%

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Transient and local two-phase heat transport at macro-scales to nano-scales

Mehrvand

Putnam

2018

Commun Phys

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Two-phase cooling has become a promising method for improving the sustainability and efficiency of high energy-density and power-density devices. Fundamentally, however, two-phase thermal transport is not well understood for local, transient processes, especially at critical to near-critical heat fluxes at the macro, micro, and nano-scales. Here we report spatiotemporal characterization of the single-bubble ebullition cycle in a hot-spot heating configuration with heat fluxes approaching 3 kW cm −2 . In particular, we experimentally reconstruct the spatiotemporal heat transfer coefficient in terms of its proportionality at both the macro-scale (l >> 1 μm) and the micro-to-nanoscale (l < 1 μm). We show that the maximum rates of heat transfer occur during the microlayer evaporation stage of the ebullition cycle, corresponding to critical maxima in the heat transfer coefficient of~160 ± 40 kW m −2 K −1 and~5300 ± 300 kW m −2 K −1 at the macro-scale and micro-to-nanoscale, respectively.

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Section: Onb Wmentioning

confidence: 86%

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confidence: 99%

Transient and local two-phase heat transport at macro-scales to nano-scales

Mehrvand

Putnam

2018

Commun Phys

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“…Extremely high heat fluxes of ~700 W/cm 2 and higher have only been dissipated over very small hotspots of less than 10 mm 2 . For example, the highest reported heat flux of ~1250 W/cm 2 [24] was attained over a very small hotspot of 0.6 mm 2 . As the heater sizes increase, the dryout heat fluxes are reduced.…”

Section: Discussionmentioning

confidence: 98%

Area-scalable high-heat-flux dissipation at low thermal resistance using a capillary-fed two-layer evaporator wick

Sudhakar

Weibel

Zhou³

et al. 2019

International Journal of Heat and Mass Transfer

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Follow this and additional works at: https://docs.lib.purdue.edu/coolingpubs This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact epubs@purdue.edu for additional information. Sudhakar, S.; Weibel, J. A.; Zhou, F.; Dede, E. M.; and Garimella, S V., "Area-scalable high-heat-flux dissipation at low thermal resistance using a capillary-fed two-layer evaporator wick" (2019). CTRC Research Publications. Paper 347. http://dx.doi.org/doi. AbstractA two-layer sintered porous evaporator wick for use in vapor chambers is shown to offer very high performance in passive high-heat-flux dissipation over large areas at a low thermal resistance. The twolayer wick has an upper cap layer dedicated to capillary liquid feeding of a thin base layer below that supports boiling. An array of vertical posts bridges these two layers for liquid feeding, while vents in the cap layer provide an unimpeded pathway for vapor removal from the base wick. The two-layer wick is fabricated using a combination of sintering and laser machining processes. The thermal resistance of the wicks during boiling is characterized in a saturated environment that replicates the capillary-fed working conditions of a vapor chamber evaporator. Thermal characterization tests are first performed using conventional single-layer evaporator wicks to analyze the effect of sintered particle size on capillary-fed boiling of water. Of the particle size ranges tested, wicks sintered from 180-212 μm-diameter particles provided the best combination of high dryout heat flux and a low boiling resistance. A two-layer evaporator wick comprising particles of this optimal size and a 15 × 15 array of liquid feeding posts yielded a maximum heat flux dissipation of 485 W/cm 2 over a 1 cm 2 heat input area while also maintaining a low thermal resistance of only ~0.052 K/W. The thermal performance of the two-layer wick is compared against various hybrid and biporous evaporator wicks previously investigated in the literature. While previous wick designs are typically restricted to small areas and low power levels or high surface superheats when dissipating such heat fluxes, the unique area-scalability of the two-layer wick design allows it to achieve an unprecedented combination of high total power and low-thermal-resistance heat dissipation over larger areas than were previously possible.

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“…Inverse opals (IOs) are ordered porous media that consist of uniform pores arranged periodically to form a fluid permeable structure shown in Figure . The regular order of these porous structures makes it feasible to accurately predict the fluid transport property using single unit cell analyses and also to fine tune the structural features such as pore diameter and porosity .…”

Section: Introductionmentioning

confidence: 99%

Enhanced Capillary‐Fed Boiling in Copper Inverse Opals via Template Sintering

Zhang

Palko

Barako

et al. 2018

Adv Funct Materials

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Capillary-fed boiling of water from microporous metal surfaces is promising for low thermal resistance vapor chamber heat spreaders for hot spot management. Vapor transport through the void spaces in porous metals enables high heat fluxes at low evaporator superheat. In this work, the critical heat fluxes of capillary-fed boiling in copper inverse opal (IO) wicks that consist of uniform pores with 3D periodicity is investigated. Template sintering is used to enlarge the "necks", or hydraulic vias, that bridge adjacent IO pores of diameters from 0.6 to 2.1 µm. The enhanced neck size increases the hydraulic permeability for vapor extraction by an order of magnitude, and subsequently the CHF from 100 to 1100 W cm −2 . Modeling of the boiling limit accounts for the vapor pressure drop through an IO wick using Darcy's law at a given bubble departure rate. This work links the effect of wick structure design on the boiling crises phenomenon in microporous surfaces and demonstrates material capabilities for ultrathin and low superheat thermal management solutions for high-power-density electronic devices.

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Approaching the limits of two-phase boiling heat transfer: High heat flux and low superheat

Cited by 53 publications

References 27 publications

Transient and local two-phase heat transport at macro-scales to nano-scales

Transient and local two-phase heat transport at macro-scales to nano-scales

Area-scalable high-heat-flux dissipation at low thermal resistance using a capillary-fed two-layer evaporator wick

Enhanced Capillary‐Fed Boiling in Copper Inverse Opals via Template Sintering

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