Numerical simulation of turbulent nanofluid flow in the narrow channel with a heated wall and a spherical dimple placed on it by using of single- phase and mixture- phase models

The purpose of this study is to numerical simulation of turbulent nanofluid flow in the narrow channel with a heated wall and a spherical dimple placed on it by using of single- phase and mixture- phase models. The nanofluid flow is also simulated with homogeneous and two-phase models for volume fraction of nanoparticles 0, 2, and 4%. The results contain pressure coefficient, friction factor, heat transfer coefficient, and various contours. The results show that by increasing the depth of the cavity, the pressure coefficient becomes more negative (smaller in magnitude), indicating an amplified velocity gradient and the pressure coefficient decreases at all depths, indicating that the vortices have become stronger. Also, at a fixed cavity depth, for every 2% increase in the volume fraction of nanoparticles, the local heat transfer coefficient is enhanced by 2%. By inspection of results, we showed that, the two-phase (mixture) model overestimates the increase in the heat transfer, which is the same for different depths. Finally, the changes in the pressure coefficient of the water-Alumina nanofluid are similar to the changes in the pressure coefficient of the Water-Cu nanofluid. Furthermore, changing the volume fraction of nanoparticles does not affect the vortex strength and pressure distribution.