Numerical Investigation of Heat Transfer, Pressure Drop and Wall Shear Stress Characteristics of Al2O3-Water Nanofluid in a Square Duct

Abstract

Turbulent heat transfer, pressure drop and wall shear stress behavior of the nanofluid Al2O3-water mixture in a square duct under constant wall heat flux are investigated numerically. Single-phase approach is taken into account during the simulations. All of the nanofluid properties depend on the temperature and the nanoparticle volume concentration. The renormalization group theory RNG \({k-\varepsilon}\) model is employed in order to model turbulence. Validation tests of the numerical results are done by using water as the first working fluid. Similar models and methods are chosen for the simulation of nanofluid (Al2O3-water) flow and heat transfer. A very good agreement is realized with the previous water and nanofluid related theoretical-empirical heat transfer and pressure drop correlations. The rate of heat transfer is increased by the presence of nanofluids when compared to that of water. Increasing Re number and particle’s volumetric concentration increases the convection heat transfer coefficient, pressure drop and wall shear stress along the duct. On the other hand, this study confirmed that single-phase model approach is appropriate for the simulation of Al2O3-water flow and heat transfer.