ZERO NANOPARTICLES FLUX EFFECT ON NATURAL CONVECTION ABOUT A CYLINDER OF ELLIPTIC CROSS SECTION IN POROUS MEDIA FILLED WITH A NANOFLUID

Abstract

In this investigation, numerical analysis was performed on the zero nanoparticle flux (ZNF) effect on natural convection in a cylinder with an elliptical cross section embedded in Darcy porous media filled with a nanofluid. The boundary conditions of the cylinder with the elliptical cross section were maintained at uniform wall temperature and ZNF to ensure that the results obtained were realistic and useful. The model adopted for the nanofluid incorporated the effects of Brownian motion and thermophoresis. The non-similar governing equations were obtained by using an appropriate coordinate transformation, and then solved by the Keller box method. Comparisons with previously published work showed good agreement. Numerical data for the dimensionless temperature profiles and Nusselt numbers are presented in graphical and tabular forms for the eccentric angle (B), buoyancy ratio (Nr = 0.4), Brownian motion parameter (Nb = 0.3), thermophoresis parameter (Nt), and the Lewis number (Le). Increasing the thermophoresis parameter and the Lewis number decreased the Nusselt number. For blunt orientation, the Nusselt number first increased with increasing eccentric angle, reached a maximum, and then decreased to zero. For slender orientation, the Nusselt number decreased monotonically. The Nusselt number in the blunt configuration initially increased with an increase in the aspect ratio, attained a maximum, and then gradually decreased. For the slender configuration, the Nusselt number decreased. In this paper, the results of the investigated physical aspects of the problem are discussed in detail.