Numerical analysis of hybrid nanofluids as coolants for automotive applications

The study the laminar convective heat transfer of hybrid nanofluids in a 3D flattened tube under constant heat flux condition was carried out. The effects of Reynolds number and concentration of hybrid nanoparticles on heat transfer characteristics of MWCNT–Fe3O4/water hybrid nanofluids were numerically investigated. The simulations were performed for the Reynolds number in the range 50-1000 and for two volume concentrations of hybrid nanoparticles, 0.1% and 0.3% respectively. Results showed that the heat transfer coefficient increases with increasing volume concentration of hybrid nanoparticles and increasing Reynolds number. At low Reynolds numbers, the application of MWCNT–Fe3O4/water hybrid nanofluids in flattened tube can enhance heat transfer up to 31% compared with water (base fluid). Numerically results were validated by comparison of simulations with results available in literature.