Flow and heat transfer of nanofluid over an exponentially shrinking porous sheet with heat and mass fluxes

Abstract

Steady boundary layer flow of nanofluid past an exponentially porous shrinking sheet in presence of heat and mass fluxes is presented. In this model the combined effects of Brownian motion and thermophoresis on heat transfer and nanoparticle volume fraction are considered. Similarity transformations are used to obtain the self-similar equations which are then solved numerically using shooting technique along with fourth order Runge-Kutta method. Similarity solution depends on the suction parameter. This investigation reveals that the variable heat flux and mass flux have major significant effects on temperature field and the nanoparticle volume fraction. The wall mass transfer through the porous sheet causes an increase of fluid velocity for the first branch of solution. Temperature as well as nanoparticle volume fraction decreases for both branches of solutions. For the Brownian motion, the temperature increases but the nanoparticle volume fraction decreases. Heat transfer rate becomes lower with the increase of Lewis number. Due to increase in thermophoresis parameter, both the temperature and nanoparticle volume fraction increase.