Two phase convective cooling for ultra-high power dissipation in microprocessors

Kottke, Peter A.; Green, Craig E.; Joshi, Yogendra; Fedorov, Andrei G.

doi:10.1109/itherm.2014.6892282

Cited by 4 publications

(4 citation statements)

References 8 publications

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“…As the microgap hydraulic diameter decreases, this boiling mechanism becomes more prevalent due to increased bubble confinement [2]. In the absence of fundamental understanding of two-phase flow in microgaps, empirical correlations are generally used to predict heat transfer coefficient, CHF and pressure drop, often for a limited range of operating conditions that cannot be extrapolated to variations in geometry or coolant [14,17,[19][20][21][22][23]. Heavy reliance on empirical correlations for predicting twophase behavior in microgaps is a major limitation in this field of study.…”

Section: Introductionmentioning

confidence: 99%

Flow regimes and convective heat transfer of refrigerant flow boiling in ultra-small clearance microgaps

Nasr

Green

Kottke

et al. 2017

International Journal of Heat and Mass Transfer

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Understanding two-phase convective heat transfer under extreme conditions of high heat and mass fluxes and confined geometry is of fundamental interest and practical significance. In particular, next generation electronics are becoming thermally limited in performance, as integration levels increase due to the emergence of ‗hotspots' featuring up to ten-fold increase in local heat fluxes, resulting from non-uniform power distribution. An ultra-small clearance, 10 μm microgap, was investigated to gain insight into physics of high mass flux refrigerant R134a flow boiling, and to assess its utility as a practical solution for hotspot thermal management. Two configurations -a bare microgap, and inline micro-pin fin populated microgap -were tested in terms of their ability to dissipate heat fluxes approaching 1.5 kW/cm 2 . Extreme flow conditions were investigated, including mass fluxes up to 3,000 kg/m 2 s at inlet pressures up to 1.5MPa and 2 exit vapor qualities approaching unity. Dominant flow regimes were identified and correlated to two phase heat transfer coefficients obtained using model-based data reduction for both device configurations. The results obtained were compared to predictions using correlations from literature, with the maximum heat transfer coefficient reaching 1.5 MW/m 2 K in the vapor plume regime in the case of the finned microgap.

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Section: Introductionmentioning

confidence: 99%

Flow regimes and convective heat transfer of refrigerant flow boiling in ultra-small clearance microgaps

Nasr

Green

Kottke

et al. 2017

International Journal of Heat and Mass Transfer

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“…There have been many experimental studies for the flow boiling in parallel microchannels, whose primary drawbacks are the flow instability and relatively high pressure drop. The bubbles generated in the narrow microchannel can expand in both axial and widthwise direction in the growth period compared to the parallel microchannels, which greatly improves the flow instability and reduces pressure drop penalties [6][7][8] . However, the narrow microchannel has disadvantages such as relatively small heat transfer area and heat transfer coefficient.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Local Subcooled Flow Boiling Heat Transfer in a Vertical Mini-Gap Channel

Feng

Coyle

et al. 2016

ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels

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An experimental study of subcooled flow boiling in a high-aspect-ratio, one-sided heating rectangular mini-gap channel was conducted using deionized water. The local heat transfer coefficient, onset of nucleate boiling, and flow pattern of subcooled boiling were investigated. The influence of heat flux and mass flux were studied with the aid of a high-speed camera. The results show that the flow pattern was mainly isolated bubbly flow when the narrow microchannel was placed vertically. The bubbles generated at lower mass fluxes were larger and did not easily depart, forming elongated bubbly flow and flowing upstream. The thin film evaporation mechanism dominated the entire test section due to the elongated bubbles and transient local dryout as well as rewet. The local heat transfer coefficient near the exit of the test section was larger.

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“…Pressure requirements are further increased by adding pin fins which have consistently been shown to improve heat transfer metrics [2]. Maintaining higher overall pressures also allows for utilization of refrigerants under two-phase flow conditions, an optimal scenario from a thermal performance standpoint [3]. Failures during experimental work have occurred for internal pressures on the order of 700 kPa, a limit which is much lower than the intermediate and long term goals of 1500 and 3000 kPa respectively to achieve 1000 W/cm 2 .…”

Section: Introductionmentioning

confidence: 99%

“…Failures during experimental work have occurred for internal pressures on the order of 700 kPa, a limit which is much lower than the intermediate and long term goals of 1500 and 3000 kPa respectively to achieve 1000 W/cm 2 . Such pressure targets would facilitate heat removal using high-performance refrigerant fluids [3].…”

Section: Introductionmentioning

confidence: 99%

Reliability study of micro-pin fin array for on-chip cooling

Woodrum

Sarvey

Bakir

et al. 2015

2015 IEEE 65th Electronic Components and Technology Conference (ECTC)

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With continued power, performance, functionality, and miniaturization demands, microelectronic devices can dissipate upwards of 50 W/cm 2 reaching to 100's of W/cm 2 and possibly 1000 W/cm 2 in the next 10 years. With such a high heat flux, traditional cooling through thermal interface material and heat spreader may not be able to remove the heat, especially from hot spots. In an ongoing research at Georgia Tech, innovative fluid-thermal solutions are being pursued where deionized water or refrigerants are circulated through an array of micro-pin fins etched into the backside of the silicon. In the proposed configuration, the thick backside of the silicon is used to etch an array of micro-pin fins and the silicon die is then bonded to another silicon or quartz substrate to create a micro-pin fin channel for fluid flow. To maximize heat flux, the fluid is expected to be in two-phase. The objective of this paper is to examine such a micro-pin fin array from the standpoint of cracking and reliability.978-1-4799-8609-5/15/$31.00 ©2015 IEEE

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Two phase convective cooling for ultra-high power dissipation in microprocessors

Cited by 4 publications

References 8 publications

Flow regimes and convective heat transfer of refrigerant flow boiling in ultra-small clearance microgaps

Flow regimes and convective heat transfer of refrigerant flow boiling in ultra-small clearance microgaps

Experimental Study on Local Subcooled Flow Boiling Heat Transfer in a Vertical Mini-Gap Channel

Reliability study of micro-pin fin array for on-chip cooling

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