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Thermal Conductivity of Packed Beds of Refractory Particles: Experimental Results
Author(s) -
Fedina Irina,
Litovsky Efim,
Shapiro Michael,
Shavit Arthur
Publication year - 1997
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1997.tb03094.x
Subject(s) - thermal conductivity , materials science , corundum , sintering , particle size , particle (ecology) , mineralogy , spinel , refractory (planetary science) , composite material , packed bed , metallurgy , chemical engineering , chemistry , chromatography , geology , oceanography , engineering
Experimental data on thermal conductivity of packed beds composed from various refractory particles (corundum, silica, magnesia, baddeleyite, yttrium oxide, spinel) obtained in the temperature range 400‐2000 K in various gases are presented. It is found that thermal conductivity of a bed composed from crushed refractory particles may change after the first and subsequent heatings. This occurs as a result of smoothing of particle surfaces and decreasing of contact heat barrier resistances between the granules. The influence of smoothing is most significant for beds composed from particles with sizes below 2 mm. In polydisperse beds, containing micrometer‐size particles, sintering processes were found to occur at temperatures above 1600 K. This led to a sharp increase of the bed thermal conductivity. In regimes where sintering did not take place, decreasing of particle size resulted in a decrease of the effective thermal conductivity. This is attributed to the increased number of contacts between the particles and the scattering of thermal radiation.