Activation energy and entropy generation in viscous nanofluid with higher order chemically reacting species
Mlamuli Dhlamini, Hiranmoy Mondal, Precious Sibanda, S. S. Motsa
Abstract
In this paper, we investigate the boundary layer flow of a steady viscous nanofluid with activation energy and a high-order chemical reaction. The flow equations are solved to a high degree of accuracy using the spectral quasi-linearisation method with residual errors less than 10−08. The changes in the local skin friction coefficient, local Nusselt number and local Sherwood number with flow parameters are analysed. Both the activation energy and order of the chemical reaction are shown to enhance the momentum and solute boundary layers while decreasing the thermal boundary layer. Increasing the activation energy and the order of the chemical reaction reduces the Bejan number, indicating that viscous dissipation and mass transfer-induced entropy dominate irreversibility of the heat transfer. The impact of particle Brownian motion and thermophoresis are also discussed in detail. Heat generation is shown to increase heat transfer irreversibility as evidenced by an increase in the Bejan number when the parameter is increased.