This study incorporated a two-step synthesis assisted by a microemulsion ultrasound technique to prepare Al2O3 nanofluid. 0.5-2.5 wt.% concentration (wt.%) nanofluid was tested for grain size, zeta potential, pH value, thermal conductivity coefficient, viscosity, and light absorption. A sedimentation experiment verified suspendibility, stability, and thermal conductivity to determine the beat mixing method. And an empirical formula for the nanofluid thermal conductivity was derived by using the intelligent dimensional analysis to examine the functional relationships between the experimental parameters. The results of the property verification and experimentation indicated that nanofluid and emulsifying agent mixture at a concentration of 1 wt.% had the best thermal conductivity, and that this decreases as the concentration increases. The suspendability and stability were the best at a concentration of 2 wt.%; there was no sedimentation at three weeks. The results also indicated that for 0.5-2.5 wt.% Al2O3 nanofluid between 20 and 40 degrees C, inserting the temperature and concentration parameters can estimate the thermal conductivity within an error rate of 3%. (C) 2017 Elsevier Ltd. All rights reserved.