ENTROPY GENERATION AND IRREVERSIBILITY ANALYSIS ON FREE CONVECTIVE UNSTEADY MHD CASSON FLUID FLOW OVER A STRETCHING SHEET WITH SORET/DUFOUR IN POROUS MEDIA

摘要

The two-dimensional unsteady incompressible Casson fluid flow over a nonlinearly stretching sheet is studied here under the influence of an external magnetic field. The nonlinear thermal radiation heat transfer in the porous media is considered. The novelty of the present study is in the entropy generation and irreversibility analysis together with the Soret and Dufour effects for Casson fluid. The fluid velocity, temperature, concentration, friction factor, entropy generation rate, and Nusselt, Sherwood, and Bejan numbers are studied through solving the governing nonlinear equations in a transformed/converted system by a shooting method. It is found that the energy transport may be maximized by varying the magnetic field and unsteadiness factor. Moreover, an increase in the porosity parameter raises the temperature and concentration profiles, while it reduces the fluid's velocity. The Bejan number is augmented due to an increase in radiation, while it is reduced due to the increases in magnetic field and Casson fluid parameter. Finally, the irreversibility ratio is augmented as the magnetic field increases.