Transient Natural Convection in an Enclosure with Variable Thermal Expansion Coefficient and Nanofluid Properties

Journal of Applied and Computational Mechanics

卷:4

Esmaeil Ghahremani¹ 

[1] Department of Energy Engineering and Physics, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Islamic Republic of Iran;

关键词: Nanofluid;    natural convection;    variable property;    transient natural convection;   

DOI  :  10.22055/jacm.2017.22206.1128

来源: DOAJ

【 摘 要 】

Transient natural convection is numerically investigated in an enclosure using variable thermal conductivity, viscosity, and the thermal expansion coefficient of Al2O3-water nanofluid. The study has been conducted for a wide range of Rayleigh numbers (103≤ Ra ≤ 106), concentrations of nanoparticles (0% ≤ ϕ ≤ 7%), the enclosure aspect ratio (AR =1), and temperature differences between the cold and hot walls (∆T= 30). Transient parameters such as development time and time-average Nusselt number along the cold wall are also presented as a non-dimensional form. Increasing the Rayleigh number shortens the non-dimensional time of the initializing stage. By increasing the volume fraction of nanoparticles, the flow development time shows different behaviors for various Rayleigh numbers. The non-dimensional development time decreases by enhancing the concentration of nanoparticles.

【 授权许可】

Unknown