An experimental study on dynamic viscosity and thermal conductivity of water-Cu-SiO2-MWCNT ternary hybrid nanofluid and the development of practical correlations

Abstract

In the present work, an experimental study has been carried out to investigate dynamic viscosity (μnf) and thermal conductivity (knf) of Cu-SiO2-MWCNT/water ternary hybrid nanofluid (THNF). The shear stress, dynamic viscosity and thermal conductivity have been measured within a temperature range of T = 15 °C to 65 °C and volume concentration range of ϕ = 1% to 3%. Furthermore, two linear mathematical correlations have been proposed to estimate dynamic viscosity and thermal conductivity of THNF. The combination of metal and metal oxide nanoparticles alongside ternary polymers nanoparticles was an innovative approach to fabricate a novel nanofluid. The nanofluid was prepared by a two-step method and the nanoparticles were dispersed into the base fluid with the help of ultrasonic waves and a three-dimensional mixer. To examine nanoparticles' surface and structure, XRD and FESEM analyses have been employed. Based on the results, both thermal conductivity and dynamic viscosity were dependent on ϕ and temperature. Also, the studied THNF exhibited Newtonian behavior throughout the experiments. Comparing the results with those of Mono nanofluid (MNF) and Binary hybrid nanofluid (BHNF), it has been observed that ternary nanoparticles, in THNF, leads to far greater thermal conductivity and dynamic viscosity than mono and binary nanoparticles, in MNFs and BHNFs. Finally, the maximum errors of the proposed mathematical models from the experimental results were 1.167% and 1.327% for thermal conductivity and dynamic viscosity correlations, respectively, with R-square values of 99.9361% and 99.8698%.