Ultra — Thin Film Evaporation (UTF) — Application to Emerging Technologies in Cooling of Microelectronics

Ohadi, Michael M.; Qi, Junyu; Lawler, John

doi:10.1007/1-4020-3361-3_17

Cited by 6 publications

(4 citation statements)

References 25 publications

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“…Moores and Joshi [14] experimentally studied the influence of tip clearances on pressure drop performance and heat transfer characteristics and showed that the influence of tip clearance on pressure drop performance was greatest at Re < 5 × 10 3 . Ohadi et al [15] provided an overview of several thermal management techniques that could serve as effective means to cool the next-generation high flux electronics. These include immersion cooling, jet impingement and spray cooling, and ultra-thin-film evaporation (UTF), particularly to serve at the chip level for hot spot cooling.…”

Section: Introductionmentioning

confidence: 99%

Forced Convective Heat Transfer Characteristics in Micro/Minicylinders Group at Low Reynolds Number

Liu

Zhang

Zhao

et al. 2012

Nanoscale and Microscale Thermophysical Engineering

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As an effective method for heat transfer enhancement, mini-or microscale pin fin arrays with different arrangements have been employed and studied in heat exchangers for nextgeneration cooling technology. A forced convective heat transfer characteristic of deionized water flowing through in-line and staggered array micro/minicylinders group plates of microcylinders was experimentally studied. Using an electricity heater, the flow rate and temperature difference between the inlet and outlet of micro/minicylinders group were measured and the Nusselt numbers were obtained over low Reynolds numbers ranging from 8 to 100. The results indicate that the experimental Nu number was less than that of the classical correlation. The height of the cylinder plays a role due to the appearance of the sluggish regions in micro/minicylinders at low Reynolds number and the combined actions of some dimensional effects, such as the conjugate heat transfer effect, the end wall effect, and the thermophysical properties with temperature variation effect, etc. The distance between the outermost cylinders and the wall of the micro/minicylinders group plate affects the experimental Nu number of a staggered array more apparently than that of an in-line array when Re > 20, which resulted from a stronger brim effect according to the present experimental results.

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Section: Introductionmentioning

confidence: 99%

Forced Convective Heat Transfer Characteristics in Micro/Minicylinders Group at Low Reynolds Number

Liu

Zhang

Zhao

et al. 2012

Nanoscale and Microscale Thermophysical Engineering

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“…However, in these systems liquid-vapor instabilities during phase-change lead to local dry-out, non-uniform temperature distributions, and significant decreases in critical heat flux [5][6][7][8][9] . In contrast, two-phase jet impingement techniques have been investigated to a much lesser extent, despite the theoretical promise of very high heat transfer coefficients (>100 W/cm 2 K) with high heat dissipation capability (>1000 W and >1000 W/cm 2 ) via thin film evaporation 2,10 . Previous experimental attempts have typically led to pool boiling due to chamber flooding, or liquid dry-out due to insufficient liquid supply 2, 11 .…”

Section: Introductionmentioning

confidence: 94%

Nanoengineered surfaces for microfluidic-based thermal management devices

2010

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Microfluidic systems offer compact and efficient thermal management strategies. In this work, we investigate novel nanostructured surfaces to control fluidic behavior and enhance heat dissipation in microfluidic systems. We fabricated silicon nanopillars ranging from 200 nm to 800 nm in diameter and heights of approximately 5 µm. In the presence of notches on the pillars, the liquid separates into multiple layers of liquid films. The thicknesses of the liquid layers subsequently increase as the film propagates, which is determined by the specific position and geometry of the notches. In the presence of asymmetric nanopillars, where the pillars have deflection angles ranging from 0-50 degrees, directional spreading of water droplets can be achieved. The liquid spreads only in the direction of the pillar deflection and becomes pinned on the opposite interface. We performed detailed measurements and developed models to predict the behavior based on pillar geometries. These studies provide insight into the complex liquid-nanostructure interactions, which show great potential to design nanostructures to achieve high flux thermal management solutions.

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“…Compared with the experimental results, the numerical predictions were in reasonable agreement with the experiments. Ohadi et al [16] overviewed several thermal management techniques that could serve as an effective means to cool the next generation high flux electronics. These included the immersion cooling, jet impingement and spray cooling, and ultra thin film evaporation (UTF), particularly to serve at the chip level for hot spot cooling of the chip.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation on heat transfer of liquid flow at low Reynolds number in micro-cylinder-groups

2012

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Heat transfer of de-ionized water over in-line and staggered micro-cylinder-groups have been numerically investigated with Reynolds number varying in the range from 25 to 150. A 3-D incompressible numerical model is employed to investigate the vortex distributions and the influences of the vortices on heat transfer characteristics at low Re numbers in micro-cylinder-groups with different geometrical parameters, including micro-cylinder diameters (100, 250 and 500 lm), ratios of pitch to microcylinder diameter (1.5, 2 and 2.5) and ratios of microcylinder height to diameter (0.5, 1, 1.5 and 2). The vortex distributions, the temperature fields, and the relationships among them are investigated by solving the numerical model with the finite volume method. It is found that the vortex number become more with the increase of pitch ratio and the change of flow rate distribution affects the heat transfer characteristics apparently. Meanwhile, the local heat transfer coefficients nearby the locations of vortices greatly increase due to the boundary layer separation, which further enhance the heat transfer in microcylinder-groups. The new correlations which to Nusselt number of de-ionized water over micro-cylinders with Re number varying from 25 to 150 have been proposed considering the differential pressure resistance and the buoyancy effect basing on numerical calculations in this paper.Pressure difference between inlet and outlet (Pa) qHeat flux (W/m 2 ) S Micro-cylinder pitch ratio (m) S w Distance between the first row and the wall (m)

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Ultra — Thin Film Evaporation (UTF) — Application to Emerging Technologies in Cooling of Microelectronics

Cited by 6 publications

References 25 publications

Forced Convective Heat Transfer Characteristics in Micro/Minicylinders Group at Low Reynolds Number

Forced Convective Heat Transfer Characteristics in Micro/Minicylinders Group at Low Reynolds Number

Nanoengineered surfaces for microfluidic-based thermal management devices

Numerical investigation on heat transfer of liquid flow at low Reynolds number in micro-cylinder-groups

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