Entropy generation minimization (EGM) for convection nanomaterial flow with nonlinear radiative heat flux

Abstract

Here entropy generation and magnetohydrodynamics (MHD) impacts in unsteady viscous nanoliquid flow are elaborated. Flow induced is by impermeable rotating disk. Application of thermodynamic second law is employed for the analysis of entropy generation. Nanofluid characteristics have been addressed through thermophoresis and Brownian movement. Nonlinear versions of mixed convection and thermal radiation are introduced simultaneously. The process of non-dimensionalization is performed via implementation of suitable variables. Nonlinear computations have been carried out. The rate of total entropy generation is evaluated for distinct arising variables. Skin-friction and Nusselt and Sherwood numbers in addition to velocity, temperature and nanoparticles concentration are emphasized. We found increasing trend in temperature and velocity for unsteadiness factor whereas opposite scenario is noticed regarding nanoparticles concentration. Entropy generation rate enhances with increasing of Brinkman number, Eckert number and magnetic parameter while the opposite behavior is recorded for Reynolds number. While Bejan number has direct relation to Eckert number, Reynolds number, and magnetic parameter, While for Brinkman number the situation is opposite. Moreover the surface acts as effective source of irreversibility when entropy generation rate is closed to the surface is higher.