Transient Natural Convection in an Enclosure with Variable Thermal Expansion Coefficient and Nanofluid Properties
عنوان مقاله: Transient Natural Convection in an Enclosure with Variable Thermal Expansion Coefficient and Nanofluid Properties
شناسه ملی مقاله: JR_JACM-4-3_001
منتشر شده در شماره 3 دوره 4 فصل در سال 1397
شناسه ملی مقاله: JR_JACM-4-3_001
منتشر شده در شماره 3 دوره 4 فصل در سال 1397
مشخصات نویسندگان مقاله:
Esmaeil Ghahremani - Department of Energy Engineering and Physics, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Islamic Republic of Iran
خلاصه مقاله:
Esmaeil Ghahremani - Department of Energy Engineering and Physics, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Islamic Republic of Iran
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.
کلمات کلیدی: Nanofluid, Natural convection, variable property, transient natural convection
صفحه اختصاصی مقاله و دریافت فایل کامل: https://civilica.com/doc/894027/