Natural Convection and Entropy Generation of Non-Newtonian Hybrid Cu-Al2O3/Water Nanofluid in an Inclined Partial Porous Cavity with Different Local Heater Positions in the Presence of Magnetic Field

Abstract

In the present paper, natural convection of non-Newtonian hybrid Cu-Al2O3 nanofluid in an inclined partial porous cavity with changing heated wall position was numerically investigated. At first, the governing equations are rewritten non-dimensionally by utilizing dimensionless parameters. Then, the entropy generation equations are expressed in non-dimensional form. The discretization of governing equations is done by CVFVM (Control Volume Finite Volume Method). The coupling between pressure and velocity is handled by SIMPLE method and the obtained algebraic equations are computed by SIP solver. Nu number and irreversibility of flow and heat transfer are examined by main parameters such as Ha number, Da number, porosity, porous media thickness, position of heated wall, power law index and angle of inclination. Nu number increases almost 39%, 50% and 52% with enhancing porous media thickness from 0.1 to 0.6 at inclination angle of -30o, 0o and 30o, respectively. The Nu number increases by setting the hot surface at the lower part of the cavity. Nu decreases almost 10.5%, 7.6% and 5.2% by augmentation of Ha number from 0.0 to 40.0 at viscosity power law index of 0.6, 1.0 and 1.4, respectively. Nu increases almost 36%, 47% and 53% at inclination angle of 30o, 0o and ‒30o by enhancing volume fraction from 0.02 to 0.12, respectively. Convection heat transfer and fluid flow will be more dominant by augmentation of permeability and Da number and this will lead to more entropy generation by fluid flow and less entropy generation and irreversibility by magnetic field and convective heat transfer process. Fluid flow and magnetic field entropy generation decrease and heat transfer irreversibility and Be number rises by porous thickness ratio. Be number and thermal entropy generation increases with porosity. However, irreversibility due to magnetic field and flow friction decreases.

Keywords

• hybrid cu-al2o3 nanofluid
• partially porous media
• position of heated wall
• da number
• porosity
• non-newtonian fluid