Buoyancy-Driven Heat Transfer of Water-Based Nanofluid in a Permeable Cylindrical Pipe With Navier Slip Through a Saturated Porous Medium

The combined effect of buoyancy-driven force, variable viscosity and Navier slip on heat transfer of unsteady water−based nanofluid flow containing copper and alumina nanoparticles in a permeable cylinder through saturated porous medium is investigated numerically. The Darcy-Brinkman-Forchheimer model was adopted to describe the flow. The non-linear partial differential equations governing the problem were obtained and solved numerically using a semi-discretization finite difference method together with Runge-Kutta-Fehlberg integration scheme. The numerical solutions for velocity, temperature, skin friction and Nusselt number have been presented graphically and discussed quantitatively. The results reveal that both nanofluid temperature and velocity are enhanced with increasing nanoparticle volume fraction and Grashof number and reduced with the increasing viscosity; Navier slip parameter; porous media resistance parameter and porous media shape factor parameter.