Pressure drop of TiO2 nanofluid in circular pipes

This paper discusses the pressure drop in circular pipes of TiO2/water nanofluid for both laminar and turbulent flows at different temperatures and TiO2 weight fractions. This study shows that TiO2/water nanofluid causes enhancement, but temperature rise reduces pressure drop. The proportional increase in pressure drop for turbulent flow is lower than that for laminar flow. The traditional equation for pressure drop fails to accurately estimate the pressure drop for laminar and turbulent flows. Accordingly, this study developed new empirical equations for the friction factor for both laminar and turbulent flows, and the maximum deviations between calculated and experimental results were reduced to within the ranges of -6.17% to 3.55% and -3.08% to 3.81%, respectively, that is, for TiO2/water nanofluid, the correlations apply better to turbulent than to laminar flow. (C) 2011 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.