Effects of Variable Fluid Properties on the Natural Convective Boundary Layer Flow of a Nanofluid Past a Vertical Plate: Numerical Study

摘要

The study of natural convective boundary-layer flow in a nanofluid past a vertical plate is investigated numerically. Physical mechanisms responsible for temperature-dependent viscosity and temperature-dependent thermal conductivity between the nanoparticles and the base fluid, such as Brownian motion and thermophoresis, are accounted for in the model. The governing partial differential equations and the boundary condition are first transformed into coupled nonlinear ordinary differential equation with appropriate boundary conditions by using a similarity transformation. Furthermore the coupled nonlinear boundary value problem with the corresponding boundary conditions are solved numerically by a second order finite difference scheme known as Keller-Box method for various values of the pertinent parameters. The result indicates: (i) the combined effects of Brownian and thermophoresis with thermal conductivity parameter leads to increase kin-friction coefficient and reduced Sherwood number whereas the opposite results show for the reduced Nusselt number; and (ii) increasing variable viscosity parameter leads to decrease the reduced Nusselt and reduced Sherwood numbers whereas the opposite results show for the skin-friction coefficient.