Analysis of Heat Transfer and Entropy Generation of TiO2-Water Nanofluid Flow in a Pipe under Transition

Single and multi-phase numerical simulations are carried out to investigate the heat transfer and entropy generation behaviour of transitional flow of TiO2-H2O nanofluid in a circular pipe. Results reveal that the small diameter of nanoparticles has the highest heat transfer rate for chi=6% and the TiO2-water nanofluid shows higher heat transfer rate using multi-phase model compared to that of the single phase model. Also no optimal Reynolds has been observed which could minimise the total entropy generation. New correlations are proposed to calculate the average Nusselt number using a nonlinear regression analysis with a standard deviation of error of less than 0.5%. (C) 2015 The Authors. Published by Elsevier Ltd.