Entropy generation of MHD micropolar nanofluid past an exponentially stretching plate with higher order power-law slip model

Abstract

Nonlinear power-law micropolar fluid (MF) distinguishes itself from other non-Newtonian fluids by the essential effects of microrotation characteristic, rheological properties and even electric conductive feature; among which microrotation as a vital factor for MF fluid flow can't be ignored. We highlight the contributions of the angle velocity and propose a mixed higher-order slip model based on it. Further, the established model is utilized to study boundary layer phenomena of MHD MF over an exponentially stretching plate. A set of numerical codes on account of collocation spectral method (CSM) is developed directly. The space derivatives are achieved with matrix multiplication (MM) and fast cosine transform (FCT) simultaneously. Entropy and Bejan number are analyzed through the second law of thermodynamics. This study reveals, for the first time, irrespective of power-law slip model may underestimate the actual temperature and concentration of the power-law MF. Consideration of the present model strengthens the attenuation effect on U distribution while diminishes the entropy generation. Viscous dissipation effect is suppressed by the increase of slip parameters. Dual directional heat and mass transfer are revealed due to the microrotation characteristic and the rheological properties of power law fluid. Nonlinear relation of Ns and the slip parameters is revealed.