CFD Studies on Hydrodynamics and Heat Transfer of Nanofluid Flow in Straight and Helical Tubes

Abstract

AbstractIn the present study, hydrodynamics and heat transfer performance were examined using a computational model for Al2O3–water and TiO2–water nanofluid flowing through the straight and helical tube of the same dimensions and under the same process conditions of laminar flow. The model was validated by comparing the computed pressure drop values of the TiO2 nanofluid with experimental results cited in the literature and were found to be within the ±2% error. The velocity and temperature contours of the flow of both nanofluids were examined in straight and helical tubes. The pressure drop was observed for TiO2 and Al2O3–water nanofluids, respectively, by varying concentrations from 1 to 2%. A comparison between the pressure drop for nanofluids was also made, and it was found that the pressure drop was lesser by 5.6% in the case of Al2O3 nanofluid as compared to TiO2. The Nusselt number versus Reynolds number data were observed for the nanofluids flowing in the straight and coiled tube. The heat transfer was found to be more in the coiled tube (10–15%) in comparison to the straight tube due to the action of secondary forces which lead to better mixing of fluids. Moreover, the heat transfer increased with velocity as well as nanofluids concentration. Hence, these nanofluids have a great potential to be used for heat transfer enhancement for various heat transfer processes.KeywordsComputational fluid dynamics (CFD)NanofluidHeat transfer