393 publications from this institution
In this study, natural convection in a concentric annulus between a cold outer square and heated inner circular cylinders in presence of static radial magnetic field is investigated numerically using the lattice Boltzmann method. The inner and outer cylinders are maintained at constant uniform temperatures and it is assumed that all walls are insulating the magnetic field. The numerical investigation is carried out for different governing parameters namely; the Hartmann number, nanoparticles volume fraction and Rayleigh number. The effective thermal conductivity and viscosity of nanofluids are calculated using the Maxwell–Garnetts (MG) and Brinkman models, respectively. Also, the multi-distribution-function (MDF) model is used for simulating the effect of uniform magnetic field. The results reveal that the average Nusselt number is an increasing function of nanoparticle volume fraction as well as the Rayleigh number, while it is a decreasing function of the Hartmann number.
In this research, combined turbulator was proposed to achieve good thermal performance. Steady turbulent flow of copper oxide nanofluid with homogeneous model was simulated involving k-ɛ model. Among various geometric parameters, height of turbulator (b) has been selected and its variation as well as Reynolds number was demonstrated in outputs. Exergy loss as well as flow and heat transfer was analyzed. Augmenting b is capable of increasing heat transfer. More disturbances can be seen with augmenting inlet velocity. Exergy loss is inversely proportional to increase of pumping power.
