Numerical Study of Natural Convection of Nanofluids in an Inclined Flat Bottom Flask Using Finite-Volume Approach

In this work, we study numerically the natural convection of nanofluids (NF) in an inclined flat bottom flask; it is one of the laboratory flasks used in organic chemistry synthesis. The main reason for this study is to enhance the thermal properties of the reaction medium inside the flat bottom flask and to ameliorate the rate of chemical reactions using nanofluids. The flat bottom wall is maintained at a constant high-temperature Th. While the top, left and right walls of the cavity are maintained at a low-temperature TL. The NF comprises Cu and Al۲O۳ NanoParticles (NP) suspended in pure water. The governing equations are solved numerically using the finite-volume approach and formulated using the Boussinesq approximation. In this simulation we examined the effects of the NP volume fraction (φ) from ۰% to ۵%, the Rayleigh number from ۱۰۳ to ۱۰۶, the various inclination angles of enclosure (γ=۰°,۵°,۱۰°, ۱۵°) and the NF type (Cu and Al۲O۳) on the flow streamlines, isotherm distribution, and Nusselt number. The obtained results show that the addition of Cu and Al۲O۳ NP increases the mean Nusselt number which enhances the heat transfer in the flat bottom flask and causes significant changes in the flow pattern. In addition, the mean Nusselt number is increased with increasing the Rayleigh number and the volume fraction, and the best results have been obtained from the Cu nanofluid. Also, as the inclination angle increases the mean Nusselt number decreases, and the highest value of the Nusselt number was obtained for a vertical enclosure (γ=۰°). The obtained streamlines are mostly symmetric and their values are generally increased by increasing the Rayleigh number and volume fractions of NPs. Besides, the obtained isotherms generally follow the geometry of the flat bottom flask.

کلیدواژه ها:

Natural convection ، Nanofluids ، Flat bottom flask ، Numerical study ، Heat transfer enhancement