Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : laminar flow

Numerical Simulation for Laminar Natural Convection with in a Vertical Heated Channel

Hussein Majeed Salih

Engineering and Technology Journal, 2011, Volume 29, Issue 11, Pages 2298-2311

A numerical investigation has been performed to estimate the induced flow rate for a laminar natural convection flow of air in a vertical channel with isothermal walls conditions (one hot and another is cold). The two-dimensional governing equations have been solved using finite volume method. The coupling between the continuity and momentum equations is solved by using the SIMPLE algorithm. After the validity of the present code by comparing results with these of previous study for the similar conditions, solutions have been obtained for Prandtl number of 0.7, aspect ratio of (4 to 20) and wall temperature difference of (10 to 30). The effects of the changes in these parameters on the induced flow rate, Grashof number and flow
patterns within the channel have been predicted. A mathematical form of flow rate correlation is presented for these cases.

Effects of Nano-Fluids Types, Volume Fraction of Nano-Particles, and Aspect Ratios on Natural Convection Heat Transfer in Right- Angle Triangular Enclosure

Israa Y. Daood

Engineering and Technology Journal, 2010, Volume 28, Issue 16, Pages 5365-5388

This 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.