Mixed convection flow about a solid sphere with a constant surface heat flux embedded in a porous medium filled with a nanofluid

Abstract

The steady laminar mixed convection boundary layer flow about a solid sphere embedded in a porous medium filled with a nanofluid, which is maintained at a constant surface heat flux, has been studied for both cases of a heated and cooled solid sphere. The resulting system of nonlinear partial differential equations is solved numerically using an implicit finite-difference scheme, namely the Keller box method. Three different types of nanoparticles are considered, namely Cu, Al2O3 and TiO2. Numerical solutions are obtained for the skin friction coefficient, the local wall temperature, the velocity and temperature profiles. The features of the flow and heat transfer characteristics for various values of the nanoparticle volume fraction and the mixed convection parameters are analyzed and discussed.