Natural convection of a pseudoplastic nanofluid in a closed cavity in the presence of a bulk heat release energy source and a heat-conducting substrate

The study analyzes the possibility of enhancement the cooling of an energy source on a heat-conducting substrate in a closed cavity filled with a pseudoplastic nanofluid in the natural convective heat transfer mode. The working medium was a carboxylmethylcellulose–water suspension with copper nanoparticles. The problem is described by differential equations in the Oberbeck–Boussinesq approximation, solved by the finite difference method, during which the influence of the determining parameters (Rayleigh number, volume fraction of nanoparticles, thickness of the heat-conducting substrate and position of the source) on the flow structure and heat transfer rate was assessed. It has been established that the most intensive cooling occurs when the energy source is located as close as possible to the cooling walls, while the volume fraction of nanoparticles should not exceed $1\%$.