Thermal conductivity graphite Table

The transmission of heat is favored by the presence of ordered crystalline lattices and covalently bonded atoms. Thus graphite, quartz, and diamond are good thermal conductors, while less-ordered forms of quartz such as glass have lower thermal conductivities. Table 7.3 contains a brief listing of thermal conductivities for a number of materials. Most polymeric materials have X values between 10 and 10° W m- K"1. 

Functional Fillers. A variety of fillers can be used to add specific properties. Metals, and beryllium and aluminum oxides, can be added to increase thermal conductivity (Table 3.33). Metals can be added to increase electrical conductivity (Table 3.34). Graphite increases lubricity and electrical conductivity. Mica increases elec-... 

All VGCF was graphitized prior to composite consolidation. Composites were molded in steel molds lined with fiberglass reinforced, non-porous Teflon release sheets. The finished composite panels were trimmed of resin flash and weighed to determine the fiber fraction. Thermal conductivity and thermal expansion measurements of the various polymer matrix composites are given in Table 6. Table 7 gives results from mechanical property measurements. 

Graphite is used widely in process plants for its high thermal conductivity (about six times that of stainless steel). Typical properties of impregnated carbon and graphite are given in Table 3.39. 

Amoco has developed a family of ultra high modulus continuous graphite fibers and preforms with axial thermal conductivity to llOOW/mK. The extremely high thermal conductivity is a direct result of an extremely high degree of crystallinity during carbonization of the mesophase pitch precursor fiber. Table... 

Electrical properties. Fillers and additives significantly increase the porosity of polytetrafluoroethylene compounds. Electrical properties are affected by the void content as well as the filler characteristics. Dielectric strength drops while dielectric constant and dissipation factor rise. Metals, carbon, and graphite increase the thermal conductivity of PTFE compounds. Tables 3.19 and 3.20 present electrical properties of a few common compounds. 

C at five different heating rates (0.5, 1, 5, 10, and 15°C/min). The thermal properties of the samples were then measured in x, y, and z directions with a Xenon flash diffusivity apparatus. The thermal conductivity of the samples was calculated from their thermal diffusivity. Table 2 lists the Z-direction thermal conductivity values for each graphitization heating rate and position within the furnace. From these data, it is clear that the thermal conductivity is directly related to the graphitization heating rate. A similar trend was observed in the crystal properties of the foams determined from X-ray diffraction (not shown here for brevity). However, it is not understood why there is a maximum at l°C/min. 

Table 2. Z-direction Thermal Conductivity (in W/m K) after Graphitization...

Nominal thermal and flow parameters were used in the fuel performance analysis except that the thermal power was increased to 102 percent of nominal full power per NRG Regulatory Guide 1.49 to account for uncertainties in core power measurements. The major thermal parameters used in the analysis are listed in Table 4.1-1. Nominal values of material properties were used in the analysis. The design correlations for the material properties of the H-451 graphite and the fuel rods account for thermal expansion, and the effects of fluence and temperature on thermal conductivity and irradiation-induced shrinkage. These thermal and flow parameters and... 

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