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Title: Thermal Conductivity within Nanoparticle Powder Beds.

Abstract

Abstract not provided.

Authors:
;
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1375578
Report Number(s):
SAND2016-7770C
646528
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Proposed for presentation at the Solid Freeform Fabrication Symposium held August 8-10, 2016 in Austin, Texas, United States.
Country of Publication:
United States
Language:
English

Citation Formats

Wilson, Mark, and Chandross, Michael E. Thermal Conductivity within Nanoparticle Powder Beds.. United States: N. p., 2016. Web.
Wilson, Mark, & Chandross, Michael E. Thermal Conductivity within Nanoparticle Powder Beds.. United States.
Wilson, Mark, and Chandross, Michael E. 2016. "Thermal Conductivity within Nanoparticle Powder Beds.". United States. doi:. https://www.osti.gov/servlets/purl/1375578.
@article{osti_1375578,
title = {Thermal Conductivity within Nanoparticle Powder Beds.},
author = {Wilson, Mark and Chandross, Michael E.},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 8
}

Conference:
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  • An investigation of the effective thermal conductivity of packed beds of spherical particles was conducted. Included is a brief review of related analytical and experimental investigations, along with a description of the results from an experimental program. Five beds of different materials were evaluated to determine the effective thermal conductivity as a function of the mechanical load on the bed, the conductivity of the bed material, and the interstitial gaseous environment surrounding the bed particles. The effective thermal conductivity of the packed beds were found to be dependent upon the thermal conductivity of the bed material sand the axial load.more » The presence of an interstitial gas increased the effective thermal conductivity of the bed by a factor of two in almost all cases. The experimental results obtained for vacuum conditions were compared with two existing analytical models that assumed elastic deformation of the spheres. The analytical models slightly underpredicted the effective thermal conductivity for hard materials with low thermal conductivities below the elastic limit for these materials. For soft materials with relatively high thermal conductivities, the analytical models overpredicted the effective thermal conductivity by as much as an order of magnitude.« less
  • The thermal conductivities (k) of beds of solid and hollow microspheres were measured using two radial heat flow techniques. One technique provided k-data at 300 K for beds with the void spaces between particles filled with argon, nitrogen, or helium from 5 kPa to 30 MPa. The other technique provided k-data with air at atmospheric pressure from 300 to 1000 K. The 300 K technique was used to study bed systems with high k-values that can be varied by changing the gas type and gas pressure. Such systems can be used to control the operating temperature of an irradiation capsule.more » The systems studied included beds of 500 ..mu..m dia solid Al/sub 2/O/sub 3/, the same Al/sub 2/O/sub 3/ spheres mixed with spheres of silica--alumina or with SiC shards, carbon spheres, and nickel spheres. Both techniques were used to determine the k-value of beds of hollow spheres with solid shells of Al/sub 2/O/sub 3/, Al/sub 2/O/sub 3//center dot/7 w/o Cr/sub 2/O/sub 3/, and partially stabilized ZrO/sub 2/. The hollow microspheres had diameters from 2100 to 3500 ..mu..m and wall thicknesses from 80 to 160 ..mu..m. 12 refs., 7 figs., 4 tabs.« less
  • The thermal conductivities of porous $sup 238$PuO$sub 2$ powder (calcined oxalate), milled powder, and high-density granules were calculated from direct measurements of steady-state temperature profiles resulting from self- heating. Thermal conductivities varied with density, temperature, and gas content of the pores. Errors caused by thermocouple heat conduction were less than 5 percent when the dimensions of the thermal conductivity cell and the thermocouple were properly selected. (auth)
  • Anomalously thick coal beds (as much as 250 ft thick) occur in the Paleocene Tongue River Member of the Fort Union Formation in the Powder River basin, Wyoming. These laterally discontinuous coal beds were deposited in raised, ombrotrophic peat bogs of fluvial environments. The coal beds include the Anderson-Canyon, Wyodak-Anderson, and Big George zones in the Powder River-Recluse area, Gillette area, and central part of the basin, respectively. The coal resources in these areas are approximately 155 billion short tons. The average maceral composition of the coals is 88% huminite (vitrinite), 5% liptinite, and 7% inertinite. The coals vary inmore » rank from subbituminous C to A (R{sub 0} values of 0.4 to 0.5%). Natural gas desorbed and produced from the coal beds and adjacent sandstones is composed mainly of methane with lesser amounts of CO{sub 2} (less than 10%). The methane is isotopically light ({delta}{sup 13}C{sup 1} values of {minus}56.7 to {minus}60.9%). Based on the chemical and isotopic composition of the gases and on the low rank of the coals, the gases are interpreted to be microbial in origin: they were generated by anaerobic bacteria that broke down the coals at low temperatures, prior to the main phase of thermogenic methane generation by devolatilization. The adsorbed amounts of methane-rich microbial gas per unit of coal in the Powder River basin are relatively low compared to amounts of thermogenic coal-bed gases from other basins. However, the total coal-bed gas resource is considered to be large (as much as several trillion cubic feet) because of the vast coal resources.« less
  • Differences in original conditions of peat formation of Tertiary coals from the Powder River basin can be determined by petrographic analysis. Samples were obtained from intervals associated with environments that we interpreted as anastomosed fluvial Arvada and Smith coals and as meandering fluvial settings, Anderson and Anderson-Dietz coals. The Smith coal is characterized by relatively low amounts of liptinites (1 to 5%), cryptoeugelinite (EG) (8 to 32%), and high amounts of cryptohumotelinite (HT) (44 to 66%). EG is degraded woody material, and HT is preserved woody material. HT is generally enriched at the base of the Smith coal, perhaps becausemore » nutrient-rich waters allowed more luxuriant plant growth there. Data for the Arvada, Anderson, and Anderson-Dietz coals showed lower amounts of preserved woody material (HT = 30-50%) and higher amounts of degraded woody material (EG = 30-60%) and liptinites (4-10%). Variations in the liptinites are the result of differences in the amounts of bituminate, fluorinite, exsudatinite, and noncellular resinite. HT is usually highest at the top and bottom of the bed or near a parting. As in the Smith coal, increases in HT probably reflect more luxuriant plant growth. Preliminary data do not show a clear petrographic distinction between coals accumulated in anastomosed and meandering fluvial systems. However, ratios of HT/EG are greater in the Smith coal than in the other beds. Sampling density is rarely sufficient to assess changes in peat chemistry caused by flooding or channel migration. At the sample locality of the Anderson-Dietz coal, however, sample control was adequate enough in three dimensions so that maceral variations could be directly associated with channel migration and backswamp flooding.« less