A novel experimental investigation on the effect of nanoparticles composition on the rheological behavior of nano-hybrids

In this study, The rheological behavior of nanofluids resulting from combination of MWCNT and Al2O3 nanoparticles in 10W40 engine oil has been investigated experimentally. The studied range of temperature was 15-55 °C from different hybrid and single nanofluids. Also, MWCNT/10W40 in three volume fractions of 0.75%-0.1%, Al2O3/10W40 in volume fractions of 0.25-1%, and mixed nanofluid of MWCNT and Al2O3 (40-60%) in volume fractions of 0.25, 0.75, and 1% were prepared. Shear rate of studied fluids was from 100 to 900 rpm. Then, experimental data were modeled by artificial neural networks. This modeling was conducted with high accuracy, which reveals that neural network is a powerful tool in modeling experimental data. The results show that all nanofluids have a similar behavior towards the increase of temperature. Increase of volume fractions of nanoparticles is also accompanied with increase of dynamic viscosity for all nanofluids. However, for MWCNT/10W40, as the amount of nanoparticles increases, the gradient of growth of dynamic viscosity increases. Findings show that increase in volume fraction does not have a significant effect on rheological behavior of nanofluids and increase in temperature decreases non-Newtonian behavior of nanofluids. However, increase in rate of MWCNT nanoparticles in nanofluid improves non-Newtonian behavior of nanofluids.