Entropy generation on double-diffusive MHD slip flow of nanofluid over a rotating disk with nonlinear mixed convection and Arrhenius activation energy

The present study deals with the swirling flow problem for the nano liquid over a radially stretchable rotating disk with the consideration of nonlinear mixed convection and chemical reaction defined by Arrhenius model. The surface of the stretchable rotating disk concedes with the Navier's velocity slip condition. The temperature jump condition due to imperfect liquid-solid energy interaction is also considered. The flow model is established by incorporating the well-known Buongiorno's nanofluid model and therefore, Brownian motion and thermophoretic diffusion are incorporated in the mathematical modeling. Heat transport is performed taking into account the heat generation owing to viscous and Joule dissipations and internal energy generation/absorption of the fluid. The coupled nonlinear partial differential equations (PDEs) are converted to the non-dimensional ordinary differential equations (ODEs) through the similarity transformation. These ODEs together with the physical conditions are then solved by the "bvp4c" technique. The impact of present flow characteristics on the entropy generation and Bejan number, flow fields (axial and radial velocities), temperature and concentration profiles are presented graphically. Moreover, the surface drag force, strength of energy and mass transport are calculated and presented in tabular forms. The outcomes show that an increase in magnetic and slip parameter values decrease the fluid velocities (axial and radial). Entropy generation gets improved with the increase in either Brinkman number or magnetic parameter values. (author)