Experimental investigation of thermal and electrical conductivity of silicon oxide nanofluids in ethylene glycol/water mixture

In this paper, the thermal conductivity and electrical conductivity of SiO2 nanofluids using mixture of ethylene glycol (EG) and water (H2O) as the base fluid are investigated. The two-step method was used to prepare SiO2-EG/H2O nanofluids with a mass concentration of 0.3%. The variations in thermal conductivity and electrical conductivity as functions of EG concentration (0-100%, v/v) and temperature (25-45 °C) are present. Experimental results showed that the thermal conductivity and electrical conductivity of SiO2-EG/H2O nanofluids both decreased as the EG content percentage increases in the EG/H2O mixture. At a specific EG content percentage, thermal conductivity and electrical conductivity both increased with the increase in temperature. To better evaluate the enhancement performance of SiO2-EG/H2O nanofluids, the relative electrical conductivity was introduced and studied explicitly. The mechanism of electrical conductivity enhancement in SiO2-EG/H2O nanofluids was analyzed in detail. Meanwhile, the ratio of thermal conductivity and electrical conductivity was also discussed.