Effects of inlet geometry on heat transfer and fluid flow of tangential micro-heat sink

Lelea, Dorin

doi:10.1016/j.ijheatmasstransfer.2010.04.018

Cited by 25 publications

(11 citation statements)

References 23 publications

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“…Configuration 3, 4 and 5 utilizes swirling flows, which has a tendency to squeeze the boundary layer and thereby enhance the local heat transfer coefficient. Research on heat transfer enhancement by swirling flows has been carried out by several authors [12] [13] [14]. The effect of this enhanced heat transfer is a lower thermal resistance due to convection and hence a lower junction temperature of the diode.…”

Section: Methodsmentioning

confidence: 99%

Water cooling of high power Light Emitting Diode

Sörensen

2012

13th InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems

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The development in light technologies for entertainment is moving towards LED based solutions. This progress is not without problems, when more than a single LED is used. The amount of generated heat is often in the same order as in a conventional discharge lamp, but the allowable operating temperature is much lower. In order to handle the higher specific power (W/m 3 ) inside the LED based lamps cold plates were designed and manufactured.6 different designs were analyzed through laboratory experiments and their performances were compared. 5 designs cover; traditional straight mini channel, S-shaped mini channel, straight mini channel with swirl, threaded mini channel with swirl and 2 parallel mini channels with swirl. In the 6 th design traditional mini channels were used. Based on the experimentally obtained heat transfer inside the cold plates, it was concluded that the mini channels utilizing swirling flow were much more efficient than channels with traditional flow without swirl. Similar conclusion was made for the design utilizing mini channels. Considering the pressure difference across the cold plate in addition to heat transfer properties, it turned out that two solutions were preferable; axial flow through mini channels or a s-channel. Experiments showed that the channel design utilizing swirling flows had up to 4 times the pressure loss as the mini channel/s-channel.

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Section: Methodsmentioning

confidence: 99%

Water cooling of high power Light Emitting Diode

Sörensen

2012

13th InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems

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“…The combination of impinging jet and microchannel cooling, which is destined to become a potential thermal management tool in the future, has attracted increasing attention, and related research studies have been performed (Chang and Dhir, 1995;Jang et al, 2003;Lelea et al, 2004;Gül, 2006;Barrau et al, 2010;Lelea, 2010;2012;Shalchi-Tabrizi and Seyf, 2012). Specifically, a new hybrid cooling scheme has been proposed for high heat flux management and power devices.…”

Section: Introductionmentioning

confidence: 99%

“…They demonstrated that, under certain conditions, up to 48.5% cooling efficiency improvement was achieved compared with that achieved with traditional microchannel design, with the maximum pressure loss reduced by 90.5%. The geometry of the tangential heat sink with straight circular microchannels was optimized (Lelea, 2010).…”

Section: Introductionmentioning

confidence: 99%

Transient thermal behavior of a microchannel heat sink with multiple impinging jets

Ming

Ding

Gui

et al. 2015

JZUS-A

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Abstract:We performed a transient numerical investigation on a microchannel heat sink with multiple impinging jets (MHSMIJ) to explore the effects on the fluid flow and heat transfer characteristics of the MHSMIJ of an unsteady impinging jet and heat flux imposed upon the substrate surface by using a computational fluid dynamics method. The heat fluxes being imposed upon the substrate surface and the inlet velocities of the jet were all set as sinusoidal functions with different amplitudes and periods with time. The effects of the amplitudes and periods of the functions on the substrate properties were analyzed. Cooling performance was evaluated by calculating the periodic average surface heat transfer coefficient, average temperature uniformity, and temperature variation of the target surfaces over a period. The results indicated that the surface heat transfer coefficient and average temperature of the cooled surface oscillated with the periodic heat fluxes, accompanied by obvious phase lags. The phase lag has a significant dependence on the periods, but little dependence on the amplitudes. The material properties of the substrate have complex influences on the transient behavior of the MHSMIJ. The periodic heat flux and periodic jet velocity significantly affected the transient thermal performance of the MHSMIJ, but had less effect on its overall performance. Further, transient heat flux and jet velocity caused non-uniform and transient temperature distributions, which will cause thermal fatigue phenomenon, and thereby have effect on the longevity of the MHSMIJ.

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“…Three-dimensional models have been developed to analyze their heat transfer characteristics, assuming conjugated solid-coolant heat transfer with fully developed flows and thermal fields [2,3,[10][11][12][13][14][15][16][17][18][19][20]. For example, Chen et al [3] proposed a threedimensional simulation to minimize the thermal resistance of a MCHS by adopting the simulated annealing method with fixed-flow power.…”

Section: Introductionmentioning

confidence: 99%

“…Kim and Mudawar [15] determined that a rectangular micro-channel with a high-aspect ratio and small fin spacing provided the best thermal performance compared to the inverse trapezoidal, triangular, trapezoidal, and diamond-shaped micro-channel. Lelea [16] presented the geometric optimization of the straight circular micro-heat sink. It is found that, for smaller tube diameters, the axial velocities are much higher than the tangential velocities, and that this has a significant influence on heat transfer.…”

Section: Introductionmentioning

confidence: 99%