Numerical Investigation of the Magnetohydrodynamic Mixed Convection inside an Extended Curved Duct in the Presence of a Nanofluid of Different Metallic Oxides Nanoparticles

The numerical work presented in this paper focuses on the influence of the magnetic field and the nanoparticles metallic nature on the hydrodynamic and thermal behavior of a nanofluid flowing in an extended curved duct. It deals with a semi-toroidal curved duct with an expanded circular section. The narrowed part of this duct from which the nanofluid enters with a cold temperature, is considered to be thermally insulated. However, the extended part is kept at a constant hot temperature. The nanoparticles used in the present study respectively are Alumina (Al2O3), copper oxide (CuO) and iron trioxide (Fe3O4). In this study, the effects of inertia, buoyancy and Lorentz forces as well as the metallic nature of the nanoparticles suspended in the pure water have been highlighted on the thermal, hydrodynamic and economic levels. The study is based on the resolution of the classical monophasic equations governing the non-isothermal flow of nanofluids by the use of finite element method, namely: the mass, momentum and energy equations. The obtained results have shown that the buoyancy and inertia forces strongly favor the global heat exchange rate. Moreover, the magnetic force acts negatively on these thermal exchanges. Furthermore, the CuO nanoparticles have demonstrated a better heat transfer rate, approximately 7% higher than that of pure water. Nevertheless, according to the economic needs, we suggest we suggest using alumina nanoparticles, as their transfer rate is comparable to that of CuO nanoparticles. It should be noted, that this study provides important insights for many industrial applications where the curved ducts are strongly presented.