Stagnation-point heat and mass transfer of MHD Maxwell nanofluids over a stretching surface in the presence of thermophoresis

Stagnation-point heat and mass transfer of MHD Maxwell nanofluids over a stretching surface in the presence of thermophoresis have been investigated. Convective heat transfer boundary condition and Brownian motion are both taken into account. The boundary layer momentum, energy and concentration governing equations based on the upper convected Maxwell constitutive model are established. With the proper similarity variables, the nonlinear partial differential equations are transformed into a set of coupled ordinary differential equations. The homotopy analysis method (HAM) with three auxiliary parameters is presented to obtain the analytical solutions in the form of exponential series functions, which shows a good agreement with the previous results. The effects of various parameters on the velocity, temperature and concentration fields are discussed graphically. Results show that the velocity and the skin friction coefficient are decreasing with the increasing of the Maxwell parameter. The larger value of the stagnation parameter is, the thinner velocity boundary layer thickness goes. The thermophoresis restricts the heat and mass transfer. The Brownian motion resists the heat flux, but promotes the mass flux. (C) 2016 Elsevier B.V. All rights reserved.