%0 Journal Article
%T Effect of Thermophoresis, Brownian and Turbulent Mass Fluxes in the Simulation of Two-Phase Turbulent Free Convection of Nanoﬂuid Inside the Enclosure using v2-f Model
%J AUT Journal of Mechanical Engineering
%I Amirkabir University of Technology
%Z 2588-2937
%A Yekani Motlagh, Saber
%D 2020
%\ 12/01/2020
%V 4
%N 4
%P 365-480
%! Effect of Thermophoresis, Brownian and Turbulent Mass Fluxes in the Simulation of Two-Phase Turbulent Free Convection of Nanoﬂuid Inside the Enclosure using v2-f Model
%K Turbulent flow
%K Natural convection
%K Nanoﬂuid
%K Buongiorno Model
%R 10.22060/ajme.2020.16761.5832
%X In this article, two-phase alumina-water turbulent natural convection with Reynolds-averaged Navier-Stokes based v2-f model in a square cavity has been investigated. Buongiorno’s two-phase model is modified for considering the nanoparticles diffusion via turbulent flow eddies. Using the ﬁnite volume method and the semi-implicit method for pressure-linked equations algorithm, the governing equations along with boundary conditions have been discretized. The left and right vertical walls of the cavity are kept at constant temperatures, while the other walls are thermally insulated. Calculations are performed for high Rayleigh numbers (107–109) and average volume fractions of nanoparticles (0 - 0.04). The results are analyzed through the thermal and dynamical ﬁelds with a particular interest in the turbulent intensity, turbulent kinetic energy, thermophoresis, Brownian and turbulent mass flux distribution inside the cavity, and Nusselt number variations. It is shown that nanoparticles had no significant effects on turbulent kinetic energy and intensity, and the thermophoresis effect is dominant at the near-wall regions. Furthermore, there are optimal average volume fractions with the maximum heat transfer rate depending on the Rayleigh number. Moreover, the magnitude of the turbulent Schmidt number had a negligible effect on the estimation of heat transfer rate. Against, low turbulent Prandtl numbers predicted higher values for the Nusselt number.
%U https://ajme.aut.ac.ir/article_4025_63c1362f63e81954dc553eb7ed1284c0.pdf