Heat transfer evaluation of single and hybrid nanofluids as cooling media in car radiators: A 3D-CFD approach in flat tubes

Abstract

Forced heat transfer of Al2O3-water, CuO-water, and TiO2-water nanofluids, Al2O3-CuO-water, Al2O3-TiO2-water, and CuO-TiO2-water nanoparticles in volumetric concentrations of 0.5%, 0.9%, and 2% were studied in a flat tube car radiator. In this work, the thermal performance of hybrid nanofluid will be compared with mono nanofluid and pure water base fluid. These nanoparticles were combined in ratios of (75:25), (50:50), and (25:75) in pure water. Mono and hybrid nanofluids with an inlet temperature of 90 °C, and in different Reynolds numbers (272–816) were studied and numerically simulated. The heat transfer performances of mono and hybrid nanofluids were determined using Nusselt number (Nu), overall heat transfer coefficient ( U), convective heat transfer coefficient ( h), and heat transfer rate ( Qa). The results show an enhancement in the thermal performances of the radiator with an increase in Reynolds number and volume concentration as follows: (Al2O3-water > Al2O3-CuO-water (75:25) > Al2O3-CuO-water (50:50) >Al2O3-CuO-water (25:75) > Al2O3-TiO2-water (75:25) > CuO-TiO2-water (75:25) > Al2O3-TiO2-water (50:50) > CuO-TiO2-water (50:50) > CuO-water > Al2O3-TiO2-water (25:75) > CuO-TiO2-water (25:75) > TiO2-water).