Transport and heat transfer of time dependent MHD slip flow of nanofluids in solar collectors with variable thermal conductivity and thermal radiation

In this paper, the unsteady magnetohydrodynamic (MHD) boundary layer slip flow and heat transfer of nanofluid in a solar collector, modeled mathematically as a nonlinear stretching sheet is investigated numerically. The variable thermal conductivity is assumed as a function of temperature and the wall-slip conditions are utilized at the boundary. The similarity transformation technique is used to reduce the governing boundary value problem to a system of nonlinear ordinary differential equations ODEs) and then solved numerically. The numerical values obtained for the velocity and temperature depend on nanofluid volume concentration parameter, unsteadiness parameter, suction/injection parameter, thermal conductivity parameter, slip parameters, MHD parameter and thermal radiation parameter. The effects of various parameters on the flow and heat transfer characteristics are presented and discussed through graphs and tables. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/).