University of Sistan and Baluchestan, Iranian Society Of Mechanical Engineers Challenges in Nano and Micro Scale Science and Technology 2821-000X 3 2 2015 06 30 Turbulent Mixed Convection of a Nanofluid in a Horizontal Circular Tube with Non-Uniform Wall Heat Flux Using a Two-Phase Approach 106 117 2038 10.7508/tpnms.2015.02.005 EN F. Vahidinia Mechanical Engineering Department, University of Zabol, Zabol, I.R. Iran M. Rahmdel Mechanical Engineering Department, University of Sistan and Baluchestan, Zahedan, I.R.Iran Journal Article 2014 11 14 In this paper, Turbulent mixed convective heat transfer of water and Al₂O₃ nanofluid has been numerically studied in a horizontal tube under non-uniform heat flux on the upper wall and insulation in the lower wall using mixture model. For the discretization of governing equations, the second-order upstream difference scheme and finite volume method were used. The coupling of pressure and velocity was established by using SIMPLEC algorithm. The calculated results demonstrated that the convective heat transfer coefficient of nanofluid is higher than of the base fluid and by increasing the nanoparticles volume fraction, the convective heat transfer coefficient and shear stress on the wall increase. On the other hand, with increasing the Grashof number, the shear stress and convective heat transfer coefficient decrease. https://chal.usb.ac.ir/article_2038_5ad7b27c5b728e1a8b956d8aaad24717.pdf