A Hybrid Microporous Copper Structure for High Performance Capillary-Driven Liquid Film Boiling

2021 ◽  
Author(s):  
Farid Soroush ◽  
Tanya Liu ◽  
Qianying Wu ◽  
Chi Zhang ◽  
Mehdi Asheghi ◽  
...  
Keyword(s):  
Heat Flux ◽  
High Performance ◽  
Copper Wire ◽  
Copper Film ◽  
Wire Mesh ◽  
High Heat Flux ◽  
Microporous Structure ◽  
Flow Loop ◽  
Large Area ◽  
Mesh Structure

Abstract Phase change thermal management devices including heat pipes and ultra-thin vapor chambers can remove and spread the excess heat from microprocessors more efficiently compared with the conventional heat sinks. However, the capillary and CHF limits of the evaporator section remained a challenge for high heat flux (> 100 Wcm−2) large area (> 5 × 5 mm2) applications. In this study, a hybrid microporous structure consists of copper wire meshes (CWMs) as the liquid delivery routing and copper inverse opals (CIOs) film as the boiling/evaporation platform is proposed. The feasibility of the approach and the design optimization were studied with extensive modeling and CFD simulations. For the experiment setup, the heater and the RTD sensors are fabricated over a Silicon chip using the conventional micro fabrication processes and the micro porous copper film is deposited based on template-assisted electrodeposition, resulting in CIOs structure with average 5 μm pore size, 1 μm neck, and 15 μm thickness. A copper wire mesh structure (500 μm thickness, 0.5 porosity, 71 μm wire diameter) with 4 × 4 tile openings (1 × 1 mm2 area per tile) was fixed over the CIOs film with mechanical constraints. A flow loop and vapor chamber are designed and fabricated to perform capillary boiling experiments in a saturated environment (liquid water and vapor at ∼100°C). The hybrid microporous structure was able to remove over 75 W from the 5 × 5 mm2 heater area (over 300 W cm−2 heat flux) with 9°C super heat resulting in thermal resistance of 0.03 cm2°CW−1 at the CHF. The findings of this study are largely beneficial for the design and fabrication of high performance evaporator wicks and next-generation heat routing technologies.

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.

Flow Boiling Enhancement in Microchannels With Diffusion Bonded Wire Mesh

2007 ◽  
Author(s):  
Hailei Wang ◽  
Richard Peterson
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flow Boiling ◽  
Nucleate Boiling ◽  
High Heat ◽  
Wire Mesh ◽  
Working Fluid ◽  
High Heat Flux ◽  
Vapor Quality ◽  
Heating Wall

Flow boiling and heat transfer enhancement in four parallel microchannels using a dielectric working fluid, HFE 7000, was investigated. Each channel was 1000 μm wide and 510 μm high. A unique channel surface enhancement technique via diffusion bonding a layer of conductive fine wire mesh onto the heating wall was developed. According to the obtained flow boiling curves for both the bare and mesh channels, the amount of wall superheat was significantly reduced for the mesh channel at all stream-wise locations. This indicated that the nucleate boiling in the mesh channel was enhanced due to the increase of nucleation sites the mesh introduced. Both the nucleate boiling dominated and convective evaporation dominated regimes were identified. In addition, the overall trend for the flow boiling heat transfer coefficient, with respect to vapor quality, was increasing until the vapor quality reached approximately 0.4. The critical heat flux (CHF) for the mesh channel was also significantly higher than that of the bare channel in the low vapor quality region. Due to the fact of how the mesh was incorporated into the channels, no pressure drop penalty was identified for the mesh channels. Potential applications for this kind of mesh channel include high heat-flux electronic cooling systems and various energy conversion systems.

On the Scalability of Liquid Microjet Array Impingement Cooling for Large Area Systems

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Avijit Bhunia ◽  
C. L. Chen
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Heat Source ◽  
Transfer Coefficient ◽  
High Heat Flux ◽  
Average Heat Transfer Coefficient ◽  
Large Area ◽  
Impingement Cooling ◽  
Average Heat

The necessity for an efficient thermal management system covering large areas is growing rapidly with the push toward more electric systems. A significant amount of research over the past 2 decades has conclusively proved the suitability of jet, droplet, or spray impingement for high heat flux cooling. However, all these research consider small heat source areas, typically about a few cm2. Can a large array of impingement pattern, covering a much wider area, achieve similar heat flux levels? This article presents liquid microjet array impingement cooling of a heat source that is about two orders of magnitude larger than studied in the previous works. Experiments are carried out with 441 jets of de-ionized water and a dielectric liquid HFE7200, each 200 μm diameter. The jets impinge on a 189 cm2 area surface, in free surface and confined jet configurations. The average heat transfer coefficient values of the present experiment are compared with correlations from the literature. While some correlations show excellent agreement, others deviate significantly. The ensuing discussion suggests that the post-impingement liquid dynamics, particularly the collision between the liquid fronts on the surface created from surrounding jets, is the most important criterion dictating the average heat transfer coefficient. Thus, similar thermal performance can be achieved, irrespective of the length scale, as long as the flow dynamics are similar. These results prove the scalability of the liquid microjet array impingement technique for cooling a few cm2 area to a few hundred cm2 area.

Site-Specific and On-Demand High Heat-Flux Cooling Using Superlattice Based Thin-Film Thermoelectrics

2009 ◽  
Author(s):  
Ihtesham Chowdhury ◽  
Ravi Prasher ◽  
Kelly Lofgreen ◽  
Sridhar Narasimhan ◽  
Ravi Mahajan ◽  
...  
Keyword(s):  
Thin Film ◽  
Heat Flux ◽  
Thermal Management ◽  
High Performance ◽  
High Heat ◽  
Thermoelectric Device ◽  
High Heat Flux ◽  
General Will ◽  
Site Specific ◽  
Fully Integrated

We have recently reported the first ever demonstration of active cooling of hot-spots of >1 kW/cm2 in a packaged electronic chip using thin-film superlattice thermoelectric cooler (TEC) cooling technology [1]. In this paper, we provide a detailed account of both experimental and theoretical aspects of this technological demonstration and progress. We have achieved cooling of as much as 15°C at a location on the chip where the heat-flux is as high as ∼1300 W/cm2, with the help of a thin-film TEC integrated into the package. To our knowledge, this is the first demonstration of high heat-flux cooling with a thin-film thermoelectric device made from superlattices when it is fully integrated into a usable electronic package. Our results, which validate the concept of site-specific micro-scale cooling of electronics in general, will have significant potential for thermal management of future generations of microprocessors. Similar active thermal management could also be relevant for high-performance solid-state lasers and power electronic chips.

Flow Boiling of Sub-Cooled Pentane on a Micro-Porous Coating

2012 ◽  
Author(s):  
Paul J. Laca ◽  
Richard A. Wirtz
Keyword(s):  
Heat Flux ◽  
High Speed ◽  
High Performance ◽  
Flow Boiling ◽  
High Heat ◽  
Surface Coatings ◽  
Porous Coating ◽  
High Heat Flux ◽  
Characteristic Curves ◽  
High Speed Video

Flow boiling experiments with sub-cooled Isopentane and n-Pentane at 3.0bar pressure assess the utility of compressed copper- and steel-filament screen laminate surface coatings as high performance boiling surfaces. High-speed video show that at high heat flux ebullition is unsteady. Isopentane and n-Pentane are found to produce nearly identical boiling characteristic curves. At the same applied heat flux, the superheat of copper filament coatings are much smaller than the steel filament coating superheats.

scholarly journals Droplet-Based Microfluidic Thermal Management Methods for High Performance Electronic Devices

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 89 ◽  
Author(s):  
Zhibin Yan ◽  
Mingliang Jin ◽  
Zhengguang Li ◽  
Guofu Zhou ◽  
Lingling Shui
Keyword(s):  
Heat Flux ◽  
Thermal Management ◽  
High Performance ◽  
Rapid Development ◽  
Electronic Devices ◽  
High Heat ◽  
High Heat Flux ◽  
Electrowetting On Dielectric ◽  
Handling Methods ◽  
Cooling Methods

Advanced thermal management methods have been the key issues for the rapid development of the electronic industry following Moore’s law. Droplet-based microfluidic cooling technologies are considered as promising solutions to conquer the major challenges of high heat flux removal and nonuniform temperature distribution in confined spaces for high performance electronic devices. In this paper, we review the state-of-the-art droplet-based microfluidic cooling methods in the literature, including the basic theory of electrocapillarity, cooling applications of continuous electrowetting (CEW), electrowetting (EW) and electrowetting-on-dielectric (EWOD), and jumping droplet microfluidic liquid handling methods. The droplet-based microfluidic cooling methods have shown an attractive capability of microscale liquid manipulation and a relatively high heat flux removal for hot spots. Recommendations are made for further research to develop advanced liquid coolant materials and the optimization of system operation parameters.

Design of Practical Liquid Metal Cooling Device for Heat Dissipation of High Performance CPUs

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Yueguang Deng ◽  
Jing Liu
Keyword(s):  
Heat Flux ◽  
Liquid Metal ◽  
Thermal Resistance ◽  
High Performance ◽  
Heat Dissipation ◽  
High Heat ◽  
High Heat Flux ◽  
Water Cooling ◽  
Cooling Device ◽  
Liquid Metal Cooling

Broad societal needs have focused attention on technologies that can effectively dissipate huge amount of heat from high power density electronic devices. Liquid metal cooling, which has been proposed in recent years, is fast emerging as a novel and promising solution to meet the requirements of high heat flux optoelectronic devices. In this paper, a design and implementation of a practical liquid metal cooling device for heat dissipation of high performance CPUs was demonstrated. GaInSn alloy with the melting point around 10°C was adopted as the coolant and a tower structure was implemented so that the lowest coolant amount was used. In order to better understand the design procedure and cooling capability, several crucial design principles and related fundamental theories were demonstrated and discussed. In the experimental study, two typical prototypes have been fabricated to evaluate the cooling performance of this liquid metal cooling device. The compared results with typical water cooling and commercially available heat pipes show that the present device could achieve excellent cooling capability. The thermal resistance could be as low as 0.13°C/W, which is competitive with most of the latest advanced CPU cooling devices in the market. Although the cost (about 70 dollars) is still relatively high, it could be significantly reduced to less than 30 dollars with the optimization of flow channel. Considering its advantages of low thermal resistance, capability to cope with extremely high heat flux, stability, durability, and energy saving characteristic when compared with heat pipe and water cooling, this liquid metal cooling device is quite practical for future application.

Design and Test of Carbon Nanotube Biwick Structure for High-Heat-Flux Phase Change Heat Transfer

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Qingjun Cai ◽  
Chung-Lung Chen
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Carbon Nanotube ◽  
Silicon Substrate ◽  
High Performance ◽  
High Heat ◽  
High Heat Flux ◽  
Resistance Variation ◽  
Variation Versus ◽  
Reliable Temperature

With the increase in power consumption in compact electronic devices, passive heat transfer cooling technologies with high-heat-flux characteristics are highly desired in microelectronic industries. Carbon nanotube (CNT) clusters have high thermal conductivity, nanopore size, and large porosity and can be used as wick structure in a heat pipe heatspreader to provide high capillary force for high-heat-flux thermal management. This paper reports investigations of high-heat-flux cooling of the CNT biwick structure, associated with the development of a reliable thermometer and high performance heater. The thermometer/heater is a 100-nm-thick and 600 μm wide Z-shaped platinum wire resistor, fabricated on a thermally oxidized silicon substrate of a CNT sample to heat a 2×2 mm2 wick area. As a heater, it provides a direct heating effect without a thermal interface and is capable of high-temperature operation over 800°C. As a thermometer, reliable temperature measurement is achieved by calibrating the resistance variation versus temperature after the annealing process is applied. The thermally oxidized layer on the silicon substrate is around 1-μm-thick and pinhole-free, which ensures the platinum thermometer/heater from the severe CNT growth environments without any electrical leakage. For high-heat-flux cooling, the CNT biwick structure is composed of 250 μm tall and 100 μm wide stripelike CNT clusters with 50 μm stripe-spacers. Using 1×1 cm2 CNT biwick samples, experiments are completed in both open and saturated environments. Experimental results demonstrate 600 W/cm2 heat transfer capacity and good thermal and mass transport characteristics in the nanolevel porous media.

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