Entropy Generation Analysis of Unsteady Magnetohydrodynamic Buoyancy‐Driven Nanofluid Flow in a Porous Vertical Channel With Thermal Radiation and Chemical Reaction

This study investigates entropy generation in an unsteady magneto‐hydrodynamic nanofluid flow with the influence of buoyancy forces embedded in a vertical porous channel. The simulation is carried out to assess the impact of thermal radiation and chemical reaction; the transport domain is bounded by a left‐cooled plate and a right‐heated plate. The schematic transport field reflects operating conditions commonly encountered in practical thermal and energy systems. The governing equations describing momentum, energy transfer, and nanoparticle concentration are nondimensionalized and solved numerically using a finite‐difference approach (FDA) to ensure stability across the computational domain. The study focuses on assessing the influence of physical parameters on the transport field and the features of the thermodynamic system. The involved parameters are velocity slip at the walls, magnetic field strength, porous medium permeability, thermal and solutal buoyancy parameters, radiation intensity, chemical reaction, Schmidt number, Brownian motion, thermophoretic, Biot number, and effects of viscous dissipation. Detailed analysis is carried out to assess the effects of varying these multi‐physical parameters on nanofluid velocity profiles, energy profiles, concentration profiles, entropy generation, as well as the Bejan number. The findings reveal that Navier slip and the magnetic field retards the motion of the nanofluid. It is further noticed that an increase in buoyance effects and porosity results in improved convection. Thermal‐dynamic irreversibility intensifies throughout the transport domain with the influence of thermal‐radiation and chemical reactions. Mechanisms of nanoparticle transport are vital in enhancing irreversibility and species concentration. More interestingly, the numerical findings prove that fine‐tuning of physical parameters on the coefficient of skin friction, Nusselt number, Sherwood number, and Bejan number have higher influence on system performance.