Numerical investigation of turbulent forced-convective heat transfer of Al2O3–water nanofluid with variable properties in tube

In this study, the flow field and heat transfer of Al2O3–water nanofluid turbulent forced convection in a tube are investigated. The surface of the tube is hot (Th = 310 K). Simulations are carried out for constant water Prandtl number of 6.13, Reynolds numbers from 10,000, 20,000, 30,000 to 100,000, nanoparticles volume fractions of 0, 0.001, 0.1, 0.2, 0.4 and nanoparticles’ diameter of 25, 33, 75, and 100 nm. The finite volume method and SIMPLE algorithm are utilized to solve the governing equations numerically. The numerical results showed that with enhancing Reynolds numbers, average Nusselt number increases. The variations of the average Nusselt number relative to volume fractions are not uniform. For all of the considered volume fractions, by increasing the Reynolds number the skin friction factor decreases and with increasing volume fractions and Reynolds number the pressure drop increases