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 SiO 2 nanofluids using mixture of ethylene glycol (EG) and water (H 2 O) as the base fluid are investigated. The two-step method was used to prepare SiO 2 -EG/H 2 O 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 SiO 2 -EG/H 2 O nanofluids both decreased as the EG content percentage increases in the EG/H 2 O 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 SiO 2 -EG/H 2 O nanofluids, the relative electrical conductivity was introduced and studied explicitly. The mechanism of electrical conductivity enhancement in SiO 2 -EG/H 2 O nanofluids was analyzed in detail. Meanwhile, the ratio of thermal conductivity and electrical conductivity was also discussed.