Analysis of entropy generation for MHD flow of third grade nanofluid over a nonlinear stretching surface embedded in a porous medium

Abstract

The main focus of present research work is to elaborate magnetohydrodynamic flow of third grade nanofluid with activation energy and binary chemical reaction. Fluid flow is generated by a nonlinearly stretched surface. Temperature and nano-concentration distributions are analyzed in the presence of Brownian motion and thermophoresis effects. The effects of Joule heating, thermal radiation and porous medium are further investigated for current analysis. Thermodynamic second mechanism is utilized to explore entropy generation rate of the system. Newly developed condition having zero mass flux of nanoparticles at the boundary is also incorporated. Partial differential equations governing the flow problem has been converted into ordinary ones using appropriate similarity variables. Builtin Shooting technique via NDsolve has been used to construct the numerical solution of the resulting problem. Impacts of various physical flow parameters are presented graphically for temperature, nano-concentration, surface drag coefficient and rates of heat trasnfer and entropy generation. It is found that impacts of third grade parameters on the thermal and nano-concentration fields are quite similar. Temperature, concentration and associated layer thicknesses are reduced via higher third grade parameters. It is established that the magnetic field restricts the flow strongly and serves as a potent control mechanism. It can be concluded that an applied magnetic field will play a major role in applications like micropumps, actuators and biomedical sensors. The activation energy aspect reduces the concentration boundary layer thickness. Total entropy of the entire system increases against higher values temperature difference variable, Brinkman number, porosity parameter, radiation parameter and magnetic parameter.