hybrid nanofluid based on cuo nanoparticles and singlewalled carbon nanotubes: optimization, thermal, and electrical properties

The purpose of this study is to use the thermal and electrical conductivities of copper oxide nanoparticlesand carbon nanotubes for the preparation of high-performance nanofluids for achieving better heattransfer properties. these nanofluids consist of a water/ethylene glycol solution containing single-wallcarbon nanotubes (swcnts) and copper oxide nanoparticles (cuonps). the effects of such independentvariables as cuonps and swcnt concentrations, ethylene glycol ratio and solution ph were optimized toenhance the thermal conductivity by the response surface method. the experimental results revealed thatadding small amounts of nanoparticles to water/ethylene glycol mixtures would improve the thermal andelectrical conductivity of nanofluids. the morphology of the nanoparticles was investigated by scanning andtransmission electron microscopy (sem & tem) and energy-dispersive x-ray spectroscopy (eds). forthe first time, the electrical conductivity of nanofluids was investigated by electrical impedance spectroscopy.the combined effects of both nanoparticles and nanotubes on thermal and electrical properties of the basefluid were compared to the influence of each on the same base fluid. the electrical and thermal conductivitiescould be enhanced by 18000 % and 157 % by addition of 0.41 % wt of swcnt and 1.15 % wt of cuonps toa 44:56 ethylene glycol-water mixture.