Thermal characteristics of graphite foam thermosyphon for electronics cooling

2005 ◽  
Vol 19 (10) ◽  
pp. 1932-1938 ◽  
Author(s):  
Kyungbin Lim ◽  
Hongkoo Roh
Keyword(s):  
Thermal Characteristics ◽  
Electronics Cooling ◽  
Graphite Foam

Thermal Characteristics of Graphite Foam Thermosyphon for Electronics Cooling

2003 ◽  
Author(s):  
Hongkoo Roh ◽  
Jungho Kim ◽  
Paul J. Boudreaux
Keyword(s):  
Thermal Conductivity ◽  
Thermal Management ◽  
Thermal Characteristics ◽  
Electronics Cooling ◽  
Liquid Level ◽  
Working Fluid ◽  
Low Density ◽  
Thermal Management Of Electronics ◽  
Graphite Foam ◽  
Density Results

Graphite foams consist of a network of interconnected graphite ligaments and are beginning to be applied to thermal management of electronics. The thermal conductivity of the bulk graphite foam is similar to aluminum, but graphite foam has one-fifth the density of aluminum. This combination of high thermal conductivity and low density results in a specific thermal conductivity about five times higher than that of aluminum, allowing heat to rapidly propagate into the foam. This heat is spread out over the very large surface area within the foam, enabling large amounts of energy to be transferred with relatively low temperature difference. For the purpose of graphite foam thermosyphon design in electronics cooling, various effects such as graphite foam geometry, sub-cooling, working fluid effect, and liquid level were investigated in this study. The best thermal performance was achieved with the large graphite foam, working fluid with the lowest boiling point, a liquid level with the exact height of the graphite foam, and at the lowest sub-cooling temperature.

Effects of Nonuniform Base Heating on Single Stack and Multi-Stack Microchannel Heat Sinks Used for Electronics Cooling

2010 ◽  
Vol 7 (2) ◽  
pp. 90-98
Author(s):  
Pradeep Hegde ◽  
K.N. Seetharamu
Keyword(s):  
Heat Sink ◽  
Flow Direction ◽  
Thermal Characteristics ◽  
Electronics Cooling ◽  
Heat Fluxes ◽  
Coolant Flow ◽  
Heat Sinks ◽  
Base Temperature ◽  
The Finite Element Method ◽  
Microchannel Heat Sinks

Numerical investigations with regard to the thermal characteristics of water cooled single stack and multistack microchannel heat sinks subjected to nonuniform base heating are conducted. Nonuniformities in base heating are accomplished by applying gradually increasing and gradually decreasing base heat fluxes with respect to coolant flow direction in the heat sink. The effects of heat concentration upstream, downstream, and in the center half of the microchannel heat sinks (similar to a hotspot) are also studied. Both parallel flow and counter coolant flow conditions in the heat sink are considered and the results are compared. The results are presented in the form of base temperature distribution and heat sink thermal resistance. The finite element method is used for the analysis.

THERMAL CHARACTERISTICS OF APOLLO 16 LUNAR FINES

1974 ◽  
Author(s):  
C. J. Cremers ◽  
H. S. Hsia ◽  
R. C. Birkebak
Keyword(s):  
Thermal Characteristics

TECHNOLOGICAL ASPECTS OF HIGH QUALITY RAW MATERIAL OBTAINING FOR PECTIN PRODUCTION

1970 ◽  
pp. 47-50
Author(s):  
I. A. Ilina ◽  
I. A. Machneva ◽  
E. S. Bakun
Keyword(s):  
Raw Materials ◽  
Thermal Characteristics ◽  
Environmental Safety ◽  
Raw Material ◽  
High Quality ◽  
Temperature Conductivity ◽  
Drying Temperature ◽  
Plant Raw Materials ◽  
Gel Forming Ability

  The article is devoted to the study of the chemical composition, physical and thermal-pfysical characteristics of damp apple pomaces and the identifying patterns of influence of drying temperature the functional composition and gel-forming ability of pectin. The research is aimed at obtaining initial data for the subsequent calculation of the main technological, hydro-mechanical, thermal, structural and economic characteristics of devices for drying the plant raw materials, ensuring the environmental safety and high quality of pectin-containing raw materials, the reducing heat and energy costs. As a result of the study of the thermal characteristics of apple pomaces, the critical points (temperature conductivity – 16.5 x 10-8 m2/s, thermal conductivity – 0.28 W/m K, heat capacity – 1627 j/(kg K)) at a humidity of 56 % are determined, which characterizing the transition from the extraction of weakly bound moisture to the extraction of moisture with strong bonds (colloidal, adsorption). It was found that the pomaces obtained from apples of late ripening have a higher content of solids (21-23 %), soluble pectin and protopectin (2.5-4.5 %). Dried pomaces obtained from apple varieties of late ripening contain up to 25 % pectin, which allow us to recommend them as a source of raw materials for the production of pectin. The optimum modes of preliminary washing of raw materials are offered, allowing to the remove the ballast substances as much as possible. It is established that when the drying temperature increases, the destructive processes are catalyzed: the strength of the pectin jelly and the uronide component and the degree of pectin esterification are reduced. The optimum drying temperature of damp apple pomaces is 80 0C, at which the quality of pectin extracted from the dried raw materials is maintained as much as possible. It is shown that the most effective for the pectin production is a fraction with a particle size of 3-5 mm, which allow us to extract up to 71 % of pectin from raw materials.

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