Comparative Study on Convection and Wall Characteristics of Al2O3-water Nanofluid Flow inside a Miniature Tube

Forced convective heat transfer and wall characteristics of nanofluid flow containing Al2O3 nanoparticles and water inside a miniature tube is studied numerically by means of computational fluid dynamic (CFD) code. Problem is solved by employing finite volume approach using both single-phase (homogeneous) and dispersion models. In both models, constant and temperature-dependent thermophysical properties are used and results are compared to available experimental and theoretical literatures.It can be seen as the Reynolds number increases, the Nusselt number improves, too. However, it is accompanied by higher wall shear stress. Moreover, in the case of temperature-dependent properties, lower values for shear stress were obtained. In comparison with experimental data and available theoretical correlations, dispersion model in both temperature-dependent and constant properties shows a desirable compatibility. On the other hand, single-phase model in constant thermophysical properties underestimates the amount of convective heat transfer. Furthermore, it can be observed at wall, by increasing the particles volume concentration, not only wall temperature decreases also, rate of thermal enhancement decreases slightly.