Synthesizes, characterization, measurements and modeling thermal conductivity and viscosity of graphene quantum dots nanofluids

The present study is aimed to measure the thermophysical properties of graphene quantum dots (GQDs) nanoparticles that dispersed in water, ethylene glycol and water-ethylene glycol mixture (60:40) as base fluids. The presence of GQDs enhance the viscosity and thermal conductivity of nanofluids considerably. The maximum thermal conductivity enhancement reaches up 53%, 21% and 18% for the nanofluid containing 0.5% GQDs at 50 degrees C in water, ethylene glycol and water-ethylene glycol mixture (60:40) as base fluids, respectively. In addition, the viscosity of each solution was measured, and the results show that it increases with increasing volume fractions of GQDs nanoparticles and decreased with increasing of temperature. Besides, an artificial neural network model presents to predict the thermal conductivity and viscosity of nanofluids. The overall predicted thermal conductivities and viscosities of nanofluids are in excellent agreement with experimental data with the MD of 1.02% and R-2 = 0.99929 for thermal conductivity and MD = 1.09%, R-2 = 0.99915 for viscosity. (C) 2019 Published by Elsevier B.V.