Comparative thermophysical and thermo-electrical performance of single, binary, and ternary (GNP–Al2O3–Fe2O3) hybrid nanofluids for heat transfer applications

Abstract

The increasing demand for thermal management systems has intensified research into advanced nanofluids with enhanced transport properties. This study experimentally investigates graphene nanoplatelet (GNP), aluminum oxide (Al 2 O 3 ), and ferric oxide (Fe 2 O 3 )-based nanofluids, spanning single-component, binary (50:50), and ternary hybrid formulations dispersed in deionized water at a fixed volume concentration of 0.1%. The impact of particle composition, particle mass ratio (PWR), and temperature (15–60 °C) on electrical conductivity ( σ ), thermal conductivity ( κ ), and dynamic viscosity ( µ ) is systematically evaluated. Nanofluids were synthesized via a two-step method, and their morphology and dispersion characteristics were examined using transmission and scanning electron microscopy. Stability assessments, including long-term observation and viscosity monitoring, confirmed consistent dispersion over extended durations. The results demonstrate that nanoparticle synergy significantly influences thermophysical behavior, with ternary systems exhibiting superior enhancements compared to single and binary counterparts. Notably, maximum improvements of 394.72% in electrical conductivity and 37.50% in viscosity were recorded at 60 °C for the ternary nanofluid sample A compared to water, while sample D achieved a 27.46% increase in thermal conductivity. To further assess application potential, heat transfer performance was evaluated using thermo-electrical conductivity ratio (TEC), performance enhancement ratio (PER), and figure of merit (Mo) for ternary nanofluid samples. Empirical correlations for ternary nanofluid samples were developed to predict property variations with temperature and particle composition, showing good agreement with experimental data. Overall, the findings highlight the strong potential of GNP–Al 2 O 3 –Fe 2 O 3 ternary hybrid nanofluids as next-generation working fluids for high-efficiency thermal systems, including heat exchangers, microchannel cooling devices, and solar thermal applications.