Abstract
How much the thermal conductivity of a liquid can be altered by dispersing a small amount of ultra-fine particles into it has been studied. Fine powders of Al2O3, SiO2 and TiO2 were used as the ultra-fine particles, and water was selected as the base liquid. Three dispersed systems were made by applying the technique of electrostatic repulsion. For the systems of water-Al2O3 and water-TiO2, effective thermal conductivities were seen to increase much more as the particle concentration was increased, but that of water-SiO2 system almost never increased. Viscosities of their dispersed systems were also measured, and the characteristics were made clear.