An empirical study on the persuasive particle size effects over the multi-physical properties of monophase MWCNT-Al2O3 hybridized nanofluids

Hybrid nanofluids are colloidal suspensions containing two different nanoparticles whose enhanced thermal properties rely upon different parameters such as properties of the base fluid and nanoparticles, in addition to particle size and shape. While few studies have reported the best particle weight ratio (PWR) based on the optimal properties, no results have been found to declare the efficient PWR based on particle sizes. The current study focuses on measuring the fluid properties of hybrid (MWCNT-Al2O3) nanofluids with 5 nm and 30 nm Al2O3 at different temperatures (15 to 55 degrees C), particle concentrations (0.025 to 0.5%), and particle weight ratio (90:10, 80:20, 60:40, 40:60. 20:80, 10:90). When 0.1% volume concentrated nanofluids were compared based on particle size, the maximum enhancement for pH and electrical conductivity (sigma) was 9.8 to 15.9% and 195.5 to 229.1% owing to the 80:20 ratio nanofluids with 5 nm Al2O3. In contrast, the viscosity and thermal conductivity enhancement were higher with 30 nm Al2O3 nanofluids by 17.5 to 21.7% for 10:90 ratio and 7.3 to 25.9% for 40:60 ratio. After measuring the properties of hybrid nanofluids with 5 nm Al2O3 at different PWR, temperature, and volume concentrations, the 90:10 ratio possessed the maximum enhancement in properties. The maximum pH, and sigma enhancement were 14.5 to 23.3%, and 238.2 to 248.3% at 0.2% concentration, whereas viscosity and thermal conductivity enhanced by 40.9 to 57.3%, and 13.7 to 45.1% at 0.5% concentration. Correlations were computed to predict relative values that have R-square values between 0.9160 and 0.9926, with a margin of deviation away from experimental values by -9.42 and + 6.83%. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study focuses on the fluid properties of hybrid nanofluids and investigates the effects of different parameters, such as temperature, particle concentration, and particle size ratio, on the properties. The results show that the particle size plays a significant role in enhancing the thermal and electrical properties of the nanofluids.