Thermo-Fluid-Stress-Deformation Analysis of Two-Layer Microchannels for Cooling Chips With Hot Spots

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Abas Abdoli ◽  
George S. Dulikravich ◽  
Genesis Vasquez ◽  
Siavash Rastkar
Keyword(s):  
Heat Flux ◽  
Thermal Stresses ◽  
Hot Spot ◽  
Heat Removal ◽  
High Heat ◽  
Heat Transfer Analysis ◽  
Deformation Analysis ◽  
High Heat Flux ◽  
Cooling Design ◽  
Microchannel Cooling

Two-layer single phase flow microchannels were studied for cooling of electronic chips with a hot spot. A chip with 2.45 × 2.45 mm footprint and a hot spot of 0.5 × 0.5 mm in its center was studied in this research. Two different cases were simulated in which heat fluxes of 1500 W cm−2 and 2000 W cm−2 were applied at the hot spot. Heat flux of 1000 W cm−2 was applied on the rest of the chip. Each microchannel layer had 20 channels with an aspect ratio of 4:1. Direction of the second microchannel layer was rotated 90 deg with respect to the first layer. Fully three-dimensional (3D) conjugate heat transfer analysis was performed to study the heat removal capacity of the proposed two-layer microchannel cooling design for high heat flux chips. In the next step, a linear stress analysis was performed to investigate the effects of thermal stresses applied to the microchannel cooling design due to variations of temperature field. Results showed that two-layer microchannel configuration was capable of removing heat from high heat flux chips with a hot spot.

STABLE, CALM, AND HIGH-HEAT-FLUX HEAT REMOVAL USING A POROUS-MICRO-CHANNEL

2017 ◽  
Author(s):  
Tomio Okawa ◽  
Junki Ohashi ◽  
Ryo Hirata ◽  
Koji Enoki
Keyword(s):  
Heat Flux ◽  
Heat Removal ◽  
High Heat ◽  
High Heat Flux ◽  
Micro Channel

Investigation of On-Chip Hot Spot Cooling Using Microchannel Heat Sink

2013 ◽  
Vol 455 ◽  
pp. 466-469
Author(s):  
Yun Chuan Wu ◽  
Shang Long Xu ◽  
Chao Wang
Keyword(s):  
Heat Flux ◽  
Heat Sink ◽  
Hot Spots ◽  
Hot Spot ◽  
High Heat ◽  
High Heat Flux ◽  
Microchannel Heat Sink ◽  
Three Dimensional Model ◽  
Spot Cooling ◽  
On Chip

With the increase of performance demands, the nonuniformity of on-chip power dissipation becomes greater, causing localized high heat flux hot spots that can degrade the processor performance and reliability. In this paper, a three-dimensional model of the copper microchannel heat sink, with hot spot heating and background heating on the back, was developed and used for numerical simulation to predict the hot spot cooling performance. The hot spot is cooled by localized cross channels. The pressure drop, thermal resistance and effects of hot spot heat flux and fluid flow velocity on the cooling of on-chip hot spots, are investigated in detail.

Dependence of Heat Transfer Coefficient on Porous Structure in Porous Media

2008 ◽  
Author(s):  
Akira Matsui ◽  
Kazuhisa Yuki ◽  
Hidetoshi Hashizume
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Porous Media ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
High Performance ◽  
Heat Removal ◽  
High Heat ◽  
Metal Foams ◽  
High Heat Flux

Detailed heat transfer characteristics of particle-sintered porous media and metal foams are evaluated to specify the important structural parameters suitable for high heat removal. The porous media used in this experiment are particle-sintered porous media made of bronze and SUS316L, and metal foams made of copper and nickel. Cooling water flows into the porous medium opposite to heat flux input loaded by a plasma arcjet. The result indicates that the bronze-particle porous medium of 100μm in pore size shows the highest performance and achieves heat transfer coefficient of 0.035MW/m2K at inlet heat flux 4.6MW/m2. Compared with the heat transfer performance of copper fiber-sintered porous media, the bronze particlesintered ones give lower heat transfer coefficient. However, the stable cooling conditions that the heat transfer coefficient does not depend on the flow velocity, were confirmed even at heat flux of 4.6MW/m2 in case of the bronze particle-sintered media, while not in the case of the copper-fiber sintered media. This signifies the possibility that the bronze-particle sintered media enable much higher heat flux removal of over 10MW/m2, which could be caused by higher permeability of the particle-sintered pore structures. Porous media with high permeability provide high performance of vapor evacuation, which leads to more stable heat removal even under extremely high heat flux. On the other hand, the heat transfer coefficient of the metal foams becomes lower because of the lower capillary and fin effects caused by too high porosity and low effective thermal conductivity. It is concluded that the pore structure having high performance of vapor evacuation as well as the high capillary and high fin effects is appropriate for extremely high heat flux removal of over 10MW/m2.

10310 A study on high heat flux heat removal with phase change using a porous metal

2014 ◽  
Vol 2014.20 (0) ◽  
pp. _10310-1_-_10310-2_
Author(s):  
Daiki Hanzawa ◽  
Kyosuke Katsumata ◽  
Tomio Okawa
Keyword(s):  
Heat Flux ◽  
Phase Change ◽  
Heat Removal ◽  
Porous Metal ◽  
High Heat ◽  
High Heat Flux

A Study on High Heat Flux Heat Removal With Boiling Using Porous Microchannel

2014 ◽  
Author(s):  
Daiki Hanzawa ◽  
Kyosuke Katsumata ◽  
Tomio Okawa
Keyword(s):  
Heat Flux ◽  
Pore Size ◽  
Mass Flux ◽  
Pressure Loss ◽  
Heat Removal ◽  
Porous Metal ◽  
High Heat ◽  
High Mass ◽  
High Heat Flux ◽  
Small Flow

This paper reports the critical heat flux (CHF) enhancement that was observed experimentally when a porous metal was placed in a small flow channel (hereafter, this channel is called a “porous microchannel”). In the porous microchannel, the CHF value increased almost linearly with increased values of the mass flux and the inlet subcooling. In consequence, higher cooling performance was achieved under high mass flux and high inlet subcooling conditions. It was also found that considerable fluctuation of the pressure loss frequently encountered in a small heated channel disappears in the porous microchannel. It was considered that the stabilization of the pressure loss can mainly be attributed to inhibition of the formation of large bubbles. The effects of the material and the pore size of the porous metal were also investigated. Silver and nickel were selected as the porous metal material and the pore size tested was 0.2 and 0.6 mm. In the present experiments, the CHF value was not influenced significantly by the material in spite of the distinct difference of the thermal conductivity between silver and nickel, whilst it was dependent noticeably on the pore size. It was hence suggested that the CHF enhancement observed in this work was mainly caused by the complex thermal-hydraulic field formed in the porous microchannel. Preliminary results of the flow visualization performed to reveal the mechanisms of the CHF enhancement in the porous microchannel was also reported.

Experimental Characterization of Two-Phase Cooling of Power Electronics in Thermosiphon and Forced Convection Modes

2021 ◽  
Vol 143 (3) ◽  
Author(s):  
Fabio Battaglia ◽  
Farah Singer ◽  
David C. Deisenroth ◽  
Michael M. Ohadi
Keyword(s):  
Heat Flux ◽  
Thermal Resistance ◽  
Power Electronics ◽  
Forced Convection ◽  
Heat Removal ◽  
High Heat ◽  
Heat Fluxes ◽  
High Heat Flux ◽  
Two Phase ◽  
Total Thermal Resistance

Abstract In this paper, we present the results of an experimental study involving low thermal resistance cooling of high heat flux power electronics in a forced convection mode, as well as in a thermosiphon (buoyancy-driven) mode. The force-fed manifold microchannel cooling concept was utilized to substantially improve the cooling performance. In our design, the heat sink was integrated with the simulated heat source, through a single solder layer and substrate, thus reducing the total thermal resistance. The system was characterized and tested experimentally in two different configurations: the passive (buoyancy-driven) loop and the forced convection loop. Parametric studies were conducted to examine the role of different controlling parameters. It was demonstrated that the thermosiphon loop can handle heat fluxes in excess of 200 W/cm2 with a cooling thermal resistance of 0.225 (K cm2)/W for the novel cooling concept and moderate fluctuations in temperature. In the forced convection mode, a more uniform temperature distribution was achieved, while the heat removal performance was also substantially enhanced, with a corresponding heat flux capacity of up to 500 W/cm2 and a thermal resistance of 0.125 (K cm2)/W. A detailed characterization leading to these significant results, a comparison between the performance between the two configurations, and a flow visualization in both configurations are discussed in this paper.

Use of Liquid Film Evaporation in Biporous Media to Achieve High Heat Flux Over Large Areas

2005 ◽  
Author(s):  
Tadej Semenic ◽  
Ying-Yu Lin ◽  
Ivan Catton
Keyword(s):  
Heat Flux ◽  
Test Chamber ◽  
Heat Removal ◽  
High Heat ◽  
Working Fluid ◽  
Interface Temperature ◽  
High Heat Flux ◽  
Film Evaporation ◽  
Powder Diameter ◽  
Better Than

Boiling characteristics of three biporous and one monoporous sintered wick are tested. The monoporous wick has the same wick thickness as a comparable biporous wick. Diameters of the clusters of the comparable biporous wick are equal to the powder diameter of the monoporous wick. A second biporous wick has the same configuration as the first, but is sintered in a thicker layer. The third biporous wick that is tested has smaller cluster sizes then the first two. All three biporous wicks have clusters sintered from powder with the same size distribution. The results demonstrate the advantages of a biporous capillary structure. All biporous wicks reached higher critical heat flux (CHF) then the monoporous wick. Experiments show that larger clusters are better than smaller. Comparing two different wick thicknesses, we can see that even though there is a dryout region inside the thick wick, it is still able to continuously remove heat at constant superheat. No sudden changes in superheat are seen. This process of heat removal is not possible with the thin wick. The working fluid in all runs is methanol. 4-mm thick wick with powder diameter ranging from 53 to 63 microns and cluster diameter ranging from 500 to 707microns is able to remove 377W/cm2 at temperature difference 110°C. A partial pressure inside the test chamber at this heat flux is 0.68atm and the interface temperature 167°C.

Thermal Management of On-Chip Hot Spot

2009 ◽  
Author(s):  
Avram Bar-Cohen ◽  
Peng Wang
Keyword(s):  
Heat Flux ◽  
Thermal Management ◽  
Hot Spot ◽  
High Heat ◽  
High Heat Flux ◽  
Switching Speed ◽  
Primary Driver ◽  
Management Approaches ◽  
On Chip ◽  
Physical Phenomena

The rapid emergence of nanoelectronics, with the consequent rise in transistor density and switching speed, has led to a steep increase in microprocessor chip heat flux and growing concern over the emergence of on-chip “hot spots”. The application of on-chip high heat flux cooling techniques is today a primary driver for innovation in the electronics industry. In this paper, the physical phenomena underpinning the most promising on-chip thermal management approaches for hot spot remediation, along with basic modeling equations and typical results are described. Attention is devoted to thermoelectric microcoolers — using mini-contcat enhancement and in-plane thermoelectric currents, orthotropic TIM’s/heat spreaders, and phase-change microgap coolers.

scholarly journals Experimental investigation of the embedded microchannel manifold cooling for power chips

2021 ◽  
pp. 328-328
Author(s):  
Nan Zhang ◽  
Ruiwen Liu ◽  
Yanmei Kong ◽  
Yuxin Ye ◽  
Xiangbin Du ◽  
...  
Keyword(s):  
Heat Flux ◽  
Power Dissipation ◽  
Heat Dissipation ◽  
Hot Spot ◽  
High Heat ◽  
Coefficient Of Performance ◽  
Junction Temperature ◽  
High Heat Flux ◽  
Transfer Path ◽  
Thermal Test

Power chips with high power dissipation and high heat flux have caused serious thermal management problems. Traditional indirect cooling technologies could not satisfy the increasing heat dissipation requirements. The embedded cooling directly inside the chip is the hot spot of the current research, which bears greater cooling potential comparatively, due to the shortened heat transfer path and decreased thermal resistance. In this study, the thermal behaviors of the power chips were demonstrated using a thermal test chip (TTC), which was etched with microchannels on its substrate?s backside and bonded with a manifold which also fabricated with silicon wafer. The chip has normal thermal test function and embedded cooling function at the same time, and its size is 7 ? 7 ? 1.125 mm3. This paper mainly discussed the influence of width of microchannels and the number of manifold channels on the thermal and hydraulic performance of the embedded cooling structure in the single-phase regime. Compared with the conventional straight microchannel structure, the cooling coefficient of performance (COP) of the 8?-50(number of manifold distribution channels: 8, microchannel width: 50 ?m)structure is 3.38 times higher. It?s verified that the 8?-50 structure is capable of removing power dissipation of 300 W (heat flux: 1200 W/cm2) at a maximum junction temperature of 69.6 ? with pressure drop of less than90.8 kPa. This study is beneficial to promote the embedded cooling research, which could enable the further release of the power chips performance limited by the dissipated heat.

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