University of Technology-IraqEngineering and Technology Journal1681-6900281620100828Effects of Nano-Fluids Types, Volume Fraction of Nano-Particles, and Aspect Ratios on Natural Convection Heat Transfer in Right- Angle Triangular Enclosureتاثیرات نوعیة Nano-Fluid نسبة حجم الجزیئات المتناھیة الصغر والنسب الباعیة للحیز المثلث القائم الزاویة في حالة انتقال الحرارة بالحمل الحر5365538835242ENIsraa Y. DaoodJournal Article20100801This study investigates natural convection heat transfer and fluid flow
characteristic of water based nano-fluids in a right-angle triangular enclosure, where the left vertical wall is insulated, the right inclined wall is cooled, and the horizontal wall is heated by spatially varying temperature. Governing equations are solved using treamvorticity
formulation in curvilinear coordinates. Streamlines, isotherms, local and average Nusselt number, moreover to NUR factor are used to present the corresponding flow and thermal fields inside the triangular enclosure. Calculation were performed for three aspect ratio of enclosure geometry (AR=0.5, 1, 2), solid volume fractions of nanoparticles ranging from PHI=0, to 4%, and Rayleigh number varying from 104 to 106. Three types of nano-particles are taken into consideration: Cu, Al 2O3, and TiO2. The results show that, the average heat transfer rate increases significantly as particle volume
fraction and Rayleigh number increase. Also, the type of nano-fluid is a key factor for heat transfer enhancement where the high values are obtained when using Cu, TiO2, and Al2O3 nano-particles respectively. Finally, it is observed that the aspect ratio of the enclosure is one of the most important on flow and heat transfer. Increasing the AR leads
that to increase the flow strength and heat transfer rate.https://etj.uotechnology.edu.iq/article_35242_6448fd370aa76f0be9bb007d277fb8d3.pdf