Analysis of Particle Dispersion and Entropy Generation in Turbulent Mixed Convection of CuO-Water Nanofluid

In the present study, turbulent mixed convection of CuO-water nanofluid is investigated in a vertical duct. In order to simulate the nanofluid flow, the fluid phase is considered as continuous whilst the discrete particles are dispersed through it. The dispersion of CuO nanoparticles at different Reynolds numbers is studied to predict the effective mechanisms concerning nanoparticles dispersion. Results show that in the turbulent fully developed region of the duct, the effect of thermophoresis is more important than Brownian motion and the dispersion of particles is higher in the duct core region. However, in the entrance region, the particles are dispersed almost uniformly. Also, increasing the nanoparticles volume fraction augments the root mean square of turbulent velocity fluctuations and this enhances the convective heat transfer as compared with the laminar flow. Moreover, increasing the nanoparticle volume fraction decreases the thermal entropy generation and increases the frictional entropy generation and due to the dominance of thermal entropy generation, the total entropy generation therefore reduces.