Thermal management Carbonate

Robinson, K.E. and Edie, D.D. (1996) Microstructure and texture of pitch-based ribbon fibers for thermal management. Carbon, 34 13-.36. 

Applied Sciences, Inc. has, in the past few years, used the fixed catalyst fiber to fabricate and analyze VGCF-reinforced composites which could be candidate materials for thermal management substrates in high density, high power electronic devices and space power system radiator fins and high performance applications such as plasma facing components in experimental nuclear fusion reactors. These composites include carbon/carbon (CC) composites, polymer matrix composites, and metal matrix composites (MMC). Measurements have been made of thermal conductivity, coefficient of thermal expansion (CTE), tensile strength, and tensile modulus. Representative results are described below. 

Ting, J.-M., and Lake,. M.L., Carbon/carbon for thermal management, Proc. 16th Ann. Conf. Comp., Mat. Structures, Cocoa Beach, FL, January, 1992. 

Mesophase-pitch-based carbon fibers can have up to three times the thermal conductivity of copper. This would make them an ideal material for thermal management applications, e.g. brake disks where heat dissipation is of prime consideration. The extremely high thermal conductivity is a direct result of the extremely high degree of crystallinity obtained during carbonization of the mesophase-pitch precursor fiber. 

Thermal management of carbon-carbon composites by functionally graded fiber arrangement technique... 

The forced flow-thermal gradient CVI process (FCVI) has been shown to permit the rapid consolidation of SiC matrix composites. Recently, the FCVI process has been extended to the fabrication of carbon fiber-carbon matrix composites. Using 2D carbon cloth preforms, composite disks 0.8 cm thick have been fabricated in less than three hours a small fraction of the time required for either the resin/pitch or conventional CVI processing. Further, the FCVI process facilitates the incorporation of oxidation inhibitors within the carbon matrix and may permit obtaining a preferred crystallographic orientation that yields the high thermal conductivity required for thermal management applications. 

Due to the low operation temperature of PEMFC an extra reactor is needed to convert the carbon monoxide into hydrogen by the water gas shift reaction. The extra reactor needs water or steam supply for the water gas shift reaction and the operation temperature of the shift catalyst has to maintain. So the shift reactor has to be part of the thermal management of PEMFC system. So the thermal management of a PEMFC system becomes more complex in comparison to a SOFC system. 

The key properties in thermal management are the thermal conductivity and the coefficient of thermal expansion of polymer, metal, and ceramic matrix composites. Highly graphitic carbon whiskers offer major improvements in the thermal conductivity and density of a heat sink, but their thermal conductivity is highly anisotropic and their thermal expansion does not match that of circuit material such as silicon or gallium arsenide. Diamond fibers far exceed the thermal conductivity of graphitic carbon fibers. 

Thermal management of the molten carbonate fuel cell plane. 

Biercuk M J, Llaguno M C, Radosavljevic M, Hyun J K and Johnson A T (2002) Carbon nanotube composites for thermal management, Appl Phys Lett 80 2767-2769. 

Development of new membrane materials that have the capability of sustaining proton conduction under low KM cmiditions and at temperatures as high as 120°C has been a struggle. Such a membrane would allow facile water management and also reduce thermal management issues in the stack. Of the two desired properties, a membrane that operates at low KM with sufficient conductivity is more critical since catalyst (both platinum and carbon) degradatirm is also suppressed under these conditions. 

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