Thermal Conductivity Of Packed Beds Of Refractory Particles: Experimental Results

Experimental data on thermal conductivity of packed peds composed from various refractory particles (corundum, silica, magneisa, baddeleyite, yttrium oxide, spinel) obtained in the temperature range 400-2000K 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. In polydisperse beds, containing micrometer-size particles, sintering processes were found to occur at temperatures above 1600K. This led to a sharp increase of the bed thermal conductivity.