LAUSR

In this paper, a three-dimensional analysis is used to study the heat transfer and fluid flow characteristics in ducts with various cross-sectional areas using GO + Co 3 O 4 /water (H 2 O) hybrid nanofluids. Four types of geometries (flat, elliptical and circular ducts) with the same hydraulic diameter were investigated. All simulations were performed for inlet velocities within the range 0.043–0.347 m s −1 . The heat transfer, pressure drop, dimensionless entropy generation and modified dimensionless entropy generation were investigated considering the nanoparticle volume concentrations between 0.10 and 0.20%. The results indicate that the flat duct has higher heat transfer coefficients up to 44% than the circular duct. Additionally, the circular duct has 20% lower pressure drop compared to the flat duct. For the flat duct, the maximum reduction in modified dimensionless entropy generation was 39.59% compared to the circular duct for a concentration of 0.2% GO + Co 3 O 4 hybrid nanoparticles. Finally, the performance evaluation criteria were computed and comparative analysis for all studied geometries was performed. Results indicated that the type of geometry has a significant effect on the heat transfer and fluid flow characteristics in ducts than the concentration of hybrid nanoparticles.