|Stability, viscosity and thermal conductivity of ZnO-water-ethylene glycol nanofluids: An experimental investigation|
Abstract The use of nanoparticles enhances heat transfer of the nanofluid as it improves the thermal conductivity. In this paper, the addition of zinc oxide (ZnO) nanoparticles to ethylene glycol + water (EG: 75% and 25%) blend was tested. Different mass fractions of ZnO (0.1, 0.5, 1.0 and 2.0%) were added to the base liquid. Nano-ZnO was mixed with EG/water blend using an ultrasonic shaker. The stability, viscosity, density and thermal conductivity of different samples were tested and analyzed. It was found that there is a clear increase in the thermal conductivity of the nanofluid compared to the base fluid, which reaches 133%. The density of the nanofluid when adding 2.0% ZnO was affected in a limited way, as the increase in density did not exceed 0.085%. Also, it was found that the increase in the viscosity of the ZnO nanofluid suspension for the same addition percentage reaches 2.18%. The nanofluid stability was evaluated using zeta potential. The results showed that the prepared samples stability were high. The most stable nanofluid samples are 0.1% and 0.5%, respectively. The least stable nanofluid sample was 2.0% compared to the other samples. However, it is still very stable, reaching 48 mV. Furthermore, a camera-imaging method was used to confirm stabilization.