Constraints on Nanoparticle Addition in Natural-Convection Heat Transfer at Highly Magnetic Field

摘要

In this paper, a numerical investigation has been performed to evaluate the nanoparticle-addition restrictions to water toward the enhancement of heat transfer. The natural convection of a nanofluid in a cavity exposed to excessive magnetic field was analyzed using an in-house computational fluid dynamics code written in FORTRAN. The effect of Brownian motion on the effective thermal conductivity and effective viscosity has been taken into consideration. The influence of relevant parameters, such as Rayleigh number (103Ra107), Hartmann number (0Ha100), and nanoparticle volume concentration (00.06) on the heat transfer characteristics has been studied. The nanoparticle used in this research is CuO with H2O as a base fluid (Pr=6.2). The results showed that the enhancement in heat transfer as a result of nanoparticle addition is pertinent to the magnetic-field strength and the Rayleigh number. Consequently, the Nusselt-number enhancement ratio () due to the nanoparticle addition is unpredictable without Hartmann and Rayleigh numbers. Isocontour maps for Nusselt number have been created at different studied parameter ranges (Rayleigh number, Hartmann number, and ). The validation of the developed numerical code is implemented, and a good endorsement is found with recently published results.