A new correlation for predicting the thermal conductivity of ZnO-Ag (50%-50%)/water hybrid nanofluid: An experimental study

In this paper, a two-stage method, along with an ultrasonic device, a magnetic mixture, and acidity control technique were used to produce ZnO-Ag/water nanofluid and the test results, along with results from data analysis are presented by diagrams and tables. The effect of volume fraction (0.125-2%) and temperature (25-50 degrees C) on thermal conductivity of nanofluid was examined on thermal conductivity of a hybrid nanofluid, i.e. zinc oxide silver ZnO-Ag (50%-50%), is presented in a diagram. At the end, a model was proposed for calculating thermal conductivity of the nanofluid, based on existing data. The results show that since Brownian motion increases with raising temperature, an increase in volume fraction at higher temperatures has a greater role in increasing thermal conductivity. In low volume fractions, temperature has a weaker effect on thermal conductivity. We found that the highest relative thermal conductivity was observed in volume fraction of 2% at 50 degrees C. Also, according to the obtained results, the margin of deviation is equal to 13%. (C) 2017 Elsevier B.V. All rights reserved.