A NOVEL-APPROACH TO DETERMINE THERMAL-CONDUCTIVITY OF MICRON-SIZED FUEL-PARTICLES

A novel approach to determine absolute values of thermal conductivity of single micron-sized particles, has been developed. A particle was s uspended in an electrodynamic chamber and was unevenly irradiated to i mpose a temperature gradient within the particle, by a focused CO2 las er beam. Consequently, a photophoretic force was generated from which the particle thermal conductivity was determined. Maximum uncertainty was estimated to be about 25%. Thermal conductivity of highly porous c har particles was measured as a function temperature, in the range of 350-1150 K, showing increase of thermal conductivity with temperature.