The Overlapping Grid Spectral Collocation Method for Solving Entropy Generation in Casson Nanofluid Flow Past a Stretching Plate

Abstract

The current study investigates the intrinsic irreversibility phenomenon of a mixed convection and electrically conducting couple stress Casson fluid motion over a thermally stretching sheet. We have considered the combined effect of applied magnetic field, Brownian motion, thermal radiation, permeability, Casson parameter, and the stretching parameter on the entropy generation rate of the model. The first and second laws of thermodynamics have been applied to examine the flow problem. The obtained dimensionless structure of highly nonlinear ordinary differential equations is then solved numerically applying the overlapping grid spectral collocation method. This method has high accuracy and converges fast. The approximate solutions for velocity, temperature and concentration are used to evaluate the rate of entropy generation and some physical parameters of the flow. For engineering interest, we have obtained tabular results for the skin friction coefficient, Nusselt number, and the Sherwood number for pertinent parameters. We found that entropy generation rate is minimized when there is an increase in the applied magnetic field, thermophoresis parameter, Casson parameter, Brownian motion, and the energy variance parameter. Further, the entropy generation rate is increased by enhancing the stretching parameter, permeability parameter, the Biot number, and thermal radiation parameter.