Experimental Study of the Effect of Effective Parameters on the Thermal Conductivity of a Five-component Hybrid Nanofluid

In this study, the thermal behavior of a five-component hybrid nanofluid Al2O3(40%)/SiO2(45%)/MWCNT(15%)-Water(60%)/EG(40%) for the first time in different laboratory conditions is analyzed. The study of this nanofluid is important because of the importance of carbon nanotubes, the fact that hybrid nanofluids have special properties and the few studies with the presence of three nanoparticles and two base fluids. Experimental measurements of thermal conductivity are performed by KD2 Pro in volumetric fractions of 0.05-0.9% and temperatures of 26-50°C. TEM, SEM and XRD analysis methods are used to identify and confirm the structure and morphology of nanoparticles. The results show that the relative thermal conductivity in the high volume fraction and temperatures is much higher than the low volume fraction. This is due to the increased kinetic energy and the presence of more nanoparticles. Also, increasing the temperature has a small effect on increasing the relative thermal conductivity. The highest increase in thermal conductivity is 28.3% in volume fraction and temperature of 0.9% and 50 ° C, respectively. The lowest increase in thermal conductivity is 1.4% at 26 ° C and volume fraction of 0.05%. The proposed model for predicting the thermal conductivity of nanofluid using the response surface method is so accurate that there is a good agreement between the modeling results and laboratory data. The values of R-squared=0.9936, CV%=0.55, -1.85%<MOD< 0.91%, p-value<0.05 and F-value=1059.23 indicate good modeling accuracy. The results of sensitivity analysis also indicate an increase in sensitivity with increasing volume fraction of nanoparticles.