Pool Boiling of Mixtures for Electronics Thermal Management

2010 ◽  
Author(s):  
Aravind Sathyanarayana ◽  
Yogendra Joshi ◽  
Yunhyeok Im
Keyword(s):  
Heat Transfer ◽  
Thermal Management ◽  
Pool Boiling ◽  
Nanowire Arrays ◽  
Test Surface ◽  
Electronic Components ◽  
Fluid Mixtures ◽  
Heat Transfer Fluids ◽  
Transfer Properties ◽  
Latent Heat Of Vaporization

Electrical and chemical compatibility requirements of electronic components pose significant constraints on the choice of liquid coolants. These constraints have led to the use of fluoroinerts and Novec liquids as coolants, which are plagued by significantly lower thermal conductivity, specific heat, and latent heat of vaporization compared to water, and also a number of these chemicals have significant environmental impact. These factors necessitate the development of new heat transfer fluids with improved heat transfer properties and applicability. Mixture formulations provide an avenue for enhancing the properties of existing heat transfer fluids. These can be tuned for specific applications. Mixture formulations of Novec fluid (HFE 7200) with alcohols and ethers (HFE 7200 and methanol; HFE 7200 and ethoxybutane) are considered in this study. A 1 cm × 1 cm Silicon (Si) sample having copper nanowire arrays is used as the test surface for pool boiling. Experiments are done under saturated conditions and also at different sub-cooled conditions to investigate the thermal performance of these new fluid mixtures. Pool boiling heat transfer performance and the critical heat flux are measured for fluid mixtures and compared with the corresponding base fluid. From the pool boiling experiments, it was observed that adding methanol to pure HFE 7200 enhances the CHF of the resulting mixture and adding ethoxybutane to pure HFE 7200 reduces the incipience temperature for boiling.

scholarly journals Capillary-Limited Evaporation From Well-Defined Microstructured Surfaces

2013 ◽  
Author(s):  
Solomon Adera ◽  
Rishi Raj ◽  
Evelyn N. Wang
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Heat Flux ◽  
Phase Change ◽  
Thermal Management ◽  
Latent Heat ◽  
Thin Film Evaporation ◽  
Film Evaporation ◽  
Microstructured Surfaces ◽  
Latent Heat Of Vaporization

Thermal management is increasingly becoming a bottleneck for a variety of high power density applications such as integrated circuits, solar cells, microprocessors, and energy conversion devices. The performance and reliability of these devices are usually limited by the rate at which heat can be removed from the device footprint, which averages well above 100 W/cm2 (locally this heat flux can exceed 1000 W/cm2). State-of-the-art air cooling strategies which utilize the sensible heat are insufficient at these large heat fluxes. As a result, novel thermal management solutions such as via thin-film evaporation that utilize the latent heat of vaporization of a fluid are needed. The high latent heat of vaporization associated with typical liquid-vapor phase change phenomena allows significant heat transfer with small temperature rise. In this work, we demonstrate a promising thermal management approach where square arrays of cylindrical micropillar arrays are used for thin-film evaporation. The microstructures control the liquid film thickness and the associated thermal resistance in addition to maintaining a continuous liquid supply via the capillary pumping mechanism. When the capillary-induced liquid supply mechanism cannot deliver sufficient liquid for phase change heat transfer, the critical heat flux is reached and dryout occurs. This capillary limitation on thin-film evaporation was experimentally investigated by fabricating well-defined silicon micropillar arrays using standard contact photolithography and deep reactive ion etching. A thin film resistive heater and thermal sensors were integrated on the back side of the test sample using e-beam evaporation and acetone lift-off. The experiments were carried out in a controlled environmental chamber maintained at the water saturation pressure of ≈3.5 kPa and ≈25 °C. We demonstrated significantly higher heat dissipation capability in excess of 100 W/cm2. These preliminary results suggest the potential of thin-film evaporation from microstructured surfaces for advanced thermal management applications.

Heat Transfer Properties of Engine Oils

2005 ◽  
Author(s):  
Scott Wrenick ◽  
Paul Sutor ◽  
Harold Pangilinan ◽  
Ernest E. Schwarz
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Diesel Engine ◽  
Specific Heat ◽  
Mineral Oil ◽  
Engine Oil ◽  
Group V ◽  
Engine Oils ◽  
Heat Transfer Fluids ◽  
Transfer Properties

The thermal properties of engine oil are important traits affecting the ability of the oil to transfer heat from the engine. The larger the thermal conductivity and specific heat, the more efficiently the oil will transfer heat. In this work, we measured the thermal conductivity and specific heat of a conventional mineral oil-based diesel engine lubricant and a Group V-based LHR diesel engine lubricant as a function of temperature. We also measured the specific heat of ethylene glycol. The measured values are compared with manufacturers’ data for typical heat transfer fluids. The Group V-based engine oil had a higher thermal conductivity and slightly lower specific heat than the mineral oil-based engine oil. Both engine oils had values comparable to high-temperature heat transfer fluids.

Perspiration Nano-Patch for Hot Spot Thermal Management

2007 ◽  
Author(s):  
Shankar Narayanan ◽  
Andrei G. Fedorov ◽  
Yogendra K. Joshi
Keyword(s):  
Heat Transfer ◽  
Thermal Management ◽  
Hot Spot ◽  
Evaporative Cooling ◽  
Heat Removal ◽  
Heat Fluxes ◽  
Conceptual System ◽  
Sweeping Gas ◽  
Phase Change Heat Transfer ◽  
Latent Heat Of Vaporization

A novel cooling scheme utilizing evaporative cooling for an ultra-thin, spatially confined liquid film is described for meeting the challenge of hot spot thermal management aiming at locally removing heat fluxes in excess of 200 W/cm2. This work presents the conceptual system design and results of performance calculations supporting the feasibility of the proposed cooling scheme. The phase change heat transfer is one of the most efficient means of heat transfer due to an advantage offered by the significant latent heat of vaporization of liquids. Fundamentally, evaporation could be a much more efficient method of heat removal as compared to boiling if certain conditions are met. Theoretically, we demonstrate that if a stable monolayer of liquid can be maintained on the surface and fully dry sweeping gas (e.g., air) is blown at high velocity above this liquid monolayer one can dissipate heat fluxes of the order of several hundreds of Watts per cm2. We also show that a more volatile FC-72 can outperform water in evaporative cooling using stable liquid microfilms.

Passive Thermal Management of Excess Heat from Electronic Devices

1989 ◽  
Vol 154 ◽  
Author(s):  
John J. Glatz ◽  
Juan F. Leon
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Exchanger ◽  
Thermal Management ◽  
Electronic Devices ◽  
High Thermal Conductivity ◽  
Enabling Technology ◽  
Electronic Components ◽  
Potential Applications ◽  
General Scope

AbstractThermal management in the packaging of electronic components is fast becoming an enabling technology in the development of reliable electronics for a range of applications. The objective of the paper is to assess the feasibility of using advance high thermal conductivity pitch fiber (HTCPF) as a solution to some of the packaging problems. The general scope will include the following: identification of the candidate material and its potential applications; thermal management of the chip to board interface; thermal management of the heat within the multi-layer interconnect board (MIB); thermal management of the standard electronic module-format E (SEME); and heat transfer thru the enclosure to a remote heatsink/heat exchanger.

Enhanced Pool Boiling Performance on Micro-, Nano-, and Hybrid-Structured Surfaces

2011 ◽  
Author(s):  
Qian Li ◽  
Wei Wang ◽  
Chris Oshman ◽  
Benoit Latour ◽  
Chen Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Thermal Management ◽  
Pool Boiling ◽  
High Heat ◽  
High Heat Flux ◽  
Maximum Heat ◽  
Structured Surfaces ◽  
Maximum Heat Transfer ◽  
Functional Components

Thermal management plays an important role in both high power electronics and energy conversion systems. A key issue in thermal management is the dissipation of the high heat flux generated by functional components. In this paper, various microstructures, nanostructures and hybrid micro/nano-structures were successfully fabricated on copper (Cu) surfaces, and the corresponding pool boiling heat transfer performance was systematically studied. It is found that the critical heat flux (CHF) of hybrid structured surfaces is about 15% higher than that of the surfaces with nanowires only and micro-pillars only. More importantly, the superheat at CHF for the hybrid structured surface is much smaller than that of the micro-pillared surface (about 35%), and a maximum heat transfer coefficient (HTC) of about 90,000W/m2K is obtained. Compared with the known best pool boiling performance on biporous media, a much larger HTC and much lower superheat at a heat flux of 250W/cm2 have been obtained on the novel hybrid-structured surfaces.

Enhancement of Pool Boiling Heat Transfer Using Aligned Silicon Nanowire Arrays

2017 ◽  
Vol 9 (20) ◽  
pp. 17595-17602 ◽  
Author(s):  
Dong Il Shim ◽  
Geehong Choi ◽  
Namkyu Lee ◽  
Taehwan Kim ◽  
Beom Seok Kim ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Silicon Nanowire ◽  
Pool Boiling ◽  
Nanowire Arrays ◽  
Pool Boiling Heat Transfer ◽  
Silicon Nanowire Arrays

Pool Boiling Heat Transfer From Enhanced Surfaces to Dielectric Fluids

1982 ◽  
Vol 104 (2) ◽  
pp. 292-299 ◽  
Author(s):  
P. J. Marto ◽  
V. J. Lepere
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Past History ◽  
Pool Boiling ◽  
Heat Fluxes ◽  
Test Surface ◽  
High Flux ◽  
Flux Surface ◽  
Pool Boiling Heat Transfer ◽  
Dielectric Fluids

Pool boiling heat-transfer measurements were made using a 15.8 mm o.d. plain copper tube and three copper enhanced surfaces: a Union Carbide High Flux surface, a Hitachi Thermoexcel-E surface and a Wieland Gewa-T surface. The dielectric fluids were Freon-113 and Fluorinert FC-72, a perfluorinated organic compound manufactured to cool electronic equipment. Data were taken at atmospheric pressure, and at heat fluxes from 100 W/m2 to 200,000 W/m2. Prior to operation, each test surface was subjected to one of three aging procedures to observe the effect of surface past history upon boiling incipience. For Freon-113 the enhanced surfaces showed a two to tenfold increase in the heat-transfer coefficient when compared to a plain tube, whereas for FC-72 an increase of two to five was measured. The High Flux surface gave the best performance over the range of heat fluxes. The Gewa-T surface did not show as much of an enhancement at low fluxes as the other two surfaces, but at high fluxes its performance improved. In fact, it was the only surface tested which delayed the onset of film boiling with FC-72. The degree of superheat required to activate the enhanced surfaces was sensitive to both past history of the surface and to fluid properties.

Nucleate Pool Boiling of Nitrogen With Different Surface Conditions

1968 ◽  
Vol 90 (4) ◽  
pp. 437-444 ◽  
Author(s):  
P. J. Marto ◽  
J. A. Moulson ◽  
M. D. Maynard
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Past History ◽  
Pool Boiling ◽  
Testing Procedure ◽  
Nucleate Boiling ◽  
Test Surface ◽  
Surface Conditions ◽  
Boiling Heat Transfer Coefficient ◽  
Teflon Coating

Pool-boiling heat transfer of liquid nitrogen from circular, 1-in.-dia horizontal disks was studied. Surface conditions included copper and nickel mirror finishes, and copper surfaces which were roughened, grease-coated, and Teflon-coated. Artificial cavities were manufactured, including mechanically drilled cylindrical holes of diameter 0.0043 and 0.015 in., and also a 0.022-in.-dia spark cut conical hole. Results indicate that a systematic testing procedure is necessary to obtain reproducible nucleate-boiling data. Surface roughness and surface material alter the nucleate-boiling curve. A grease coating significantly decreases the nucleate-boiling heat-transfer coefficient. A Teflon coating has very little effect. Past history of the test surface, including the length of time spent while boiling, can change boiling results. The effect of artificial cavities on both natural convection and nucleate-boiling was determined.

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