Thermal and hydraulic characteristics of a triangular duct using an Al₂O ₃ nanofluid in a turbulent flow regime

This paper presents the computational analysis of convective heat transfer characteristics, pressure drop, and entropy generation characteristics of Al₂O₃/water nanofluids in a noncircular duct (triangular) using a single phase approach under a turbulent flow regime. The thermal and pressure drop characteristics of different concentrations of Al₂O₃ nanoparticles (NPs) and the analysis were carried out in Fluent software using a k-ε approach under constant wall heat flux around the boundary. The results show that there is an increase in pressure drop and thereby an increase in friction by 20% for the smooth condition. The total pressure drop between the entry and exit section of the duct is increased to approximately 84.2% and 85.6% for a higher Reynolds number (Re = 10 000) compared with that of base fluid. Similarly, the entropy generation of water is increased by 40% as compared with 0.05% and 0.1% Al₂O₃ NPs. There is also a decrease in entropy generation identified while there is an increase in the Reynolds number. The convective heat transfer of 0.05% and 0.1% nanofluid has a similar trend with increased Reynolds number. The maximum performance is observed at the Reynolds number (Re = 4000) and found to be 1.29 for 0.1% concentration, whereas, the fluid at 0.05% is observed to be at 1.23. At a higher Reynolds number (Re = 10 000) the performance index decreased to approximately 1.19 and 1.25 for 0.05% and 0.1%, respectively.