NUMERICAL SIMULATION OF NATURAL CONVECTION AROUND AN OBSTACLE PLACED IN AN ENCLOSURE FILLED WITH DIFFERENT TYPES OF NANOFLUIDS

The present numerical study deals with natural convection in an enclosure with a heated cylindrical block filled with nanofiuid. The governing equations have been discretized using the finite volume method, and the SIMPLE algorithm has been used to couple velocity and pressure fields. The effect of the Rayleigh number, type, solid volume fraction of nanoparticles, radius, and position of the hot body is studied, and obtained results are presented in the form of streamline and isotherm plots, a Nusselt diagram, and comparative tables. Water, Cu-water, and Al2O3-water have been utilized as working fluids. In this study, the particle diameters of Cu and Al2O3 nanoparticles are 90 and 47 nm, respectively. On the basis of the results, increasing solid volume fraction and Ra number causes a noticeable enhancement in the rate of heat transfer. Also, increasing the radius of the hot circular cylinder, differences in values of Nusselt number between base fluid and nanofluid significantly increase.