Thermal conductivity enhancement of Al₂O₃ nanofluids based on the mixtures of aqueous NaCl solution and CH₃OH

Adding nanoparticles into the base fluids is expected to increase the gas absorption rate of it. In this study, the methanol (CH₃OH)-based Al₂O₃ nanofluids are prepared for application of the CO₂ removal system. The suspension stability and thermal characterizations are estimated by the Tyndall effect and by measuring the thermal conductivity of the nanofluids. Arabic gum (AG) is used as a steric stabilizer and NaCl is added to examine the salts effect on the stability and thermal conductivity of it. Increasing NaCl and CH₃OH concentrations increases the thermal conductivity enhancement of the nanofluids which was attributed to the high thermal conductivity ratio of the particle and the base fluids. It is found that the thermal conductivity enhancement of the nanofluids increases with increasing the concentrations of NaCl and CH₃OH, and the highest value is obtained ∼6.34% for 10 wt% NaCl, 40 vol% CH ₃OH and 0.1 vol% particle concentrations.