An Experimental Study on SiO2-ND Hybrid Nanofluid: Thermal Conductivity, Viscosity, and Stability with New Forecast Models

Abstract

Objective: In the present investigation, thermal conductivity and viscosity properties of water-based SiO2-ND hybrid nanofluid were measured, experimentally. Methods: Nanofluids were prepared by using a two-step method and with three different (0.5%, 0.75%, and 1%) concentrations. Every concentration had three different SiO2-ND mixtures (50% SiO2 - 50% ND, 33% SiO2 - 66% ND, 66% SiO2 - 33% ND). Results: The most stable sample was measured as -33.4 mV. Measurements of viscosity and thermal conductivity were done from 20 oC to 60 oC at every 10 oC. Thermal conductivity data were measured by thermal conductivity analyzer and viscosity data were measured by tube viscometer. The highest thermal conductivity enhancement was measured for 1% SiO2 0.33: ND 0.66 at 40 oC and the highest relative dynamic viscosity was calculated as 4.19 for 1% SiO2 0.33: ND 0.66 at 40 oC. A comparison table is also given to show the zeta potential values-concentration relations. Conclusion: Finally, two different correlations for predicting thermal conductivity and viscosity were proposed for practical usage.