Entropy generation and regression analysis on stagnation point flow of Casson nanofluid with Arrhenius activation energy

This article presents the study of two-dimensional hydromagnetic stagnation point flow of Casson nanofluid over a stretching sheet in a non-Darcy porous medium with binary chemical reaction stimulated by Arrhenius activation energy. The energy equation is obtained by considering the production of heat due to Joule and viscous dissipations, heat generation/absorption and thermal radiation of the liquid. The flow model is developed and presented in the form of a system of nonlinear partial differential equations together with appropriate boundary conditions. The particle flux at the sheet is taken to be zero. The leading PDEs are transformed into dimensionless coupled ordinary differential equations (ODEs) by the usual procedure of transformation. The obtained ODEs are solved using optimal homotopy analysis method, and the effects of underlying parameters on the fluid velocity, temperature, concentration, entropy generation and Bejan number are demonstrated with the help of graphs. Also, the numerical values of skin friction coefficient, Nusselt number and Sherwood number are presented in tabular form. Linear as well as quadratic regression analysis for quantities of physical interest has also been carried out. Entropy generation is perceived to rise on increasing diffusive variable and Brinkman number, whereas Brownian diffusion has an adverse effect on it. Skin friction coefficient is reduced on increasing Casson fluid parameter and activation energy.