Characterization of thermal and electrical properties of hybrid nanofluids prepared with multi-walled carbon nanotubes and Fe2O3 nanoparticles

The thermal and electrical features of fluids are the most important parameters for designing suitable nanofluids to be used as coolants in automotive systems, transportation, power plants, industrial facilities, as well as oil, gas, petrochemical and electronic industries. This research aims at the thermal, electrical and physical properties of hybrid nanofluids that consist of multi-walled carbon nanotube (MWCNT) and Fe2O3 nanoparticles in ethylene glycol/water as base fluid. The conditions for nanofluid preparation were optimized through the response surface methodology. EG, MWCNT, Fe2O3 nanoparticles proportion and solution pH were chosen as parameters of effect on Thermal conductivity. The experimental data point out that Thermal conductivity would increase proportional to increase the amount of nanoparticle, but it would decrease in alkaline environments. Also, highest electrical conductivity (545 [mu S/cm]) was observed at 0.69 [%w.v] of MWCNT and 1.67 [% w.v] of Fe2O3 nanoparticles dispersed in a 44:56 ethylene glycol-water mixture, as compared to other base fluids. The synergetic effect of both nanoparticles added to the base fluid on the thermos-electrical property was confirmed by the measurement of thermal and electrical conductivities and electrochemical impedance spectroscopy (EIS).