Entropy generation analysis of bioconvective Darcy–Forchheimer micropolar nanofluid flow over a stretching sheet with chemical reaction and gyrotactic microorganisms

Abstract

Abstract The present work aims to investigate the entropy generation characteristics of a Darcy-Forchheimer bioconvective micropolar nanofluid flow with mixed convection, magnetic field effect, thermal radiation, chemical reaction, Brownian motion, thermophoresis effect and Cattaneo-Christov heat flux containing gyrotactic microorganisms. In this research, the fluid motion in a porous medium is modelled, and micropolar theory is used to describe the microstructure of the fluid for the particle rotation and the pair stress effects. The controlling nonlinear partial differential equations are reduced to a set of ordinary differential equations by using proper similarity transformations and solved numerically via a shooting method with the bvp5c MATLAB package. The research emphasises the combined behaviour of velocity, microrotation, temperature, nanoparticle concentration, microbe density, and entropy generation with the impact of regulating dimensionless factors. The findings illustrate that the magnetic field and porous drag suppress the fluid motion, whereas Brownian motion and thermophoresis significantly enhance the thermal and concentration transport. Also, the Entropy generation becomes more noticeable as the Brinkman number and porosity increase. Joule heating increases surface drag by 19.5 % and decreases the Nusselt number by 11.8 % as the magnetic parameter increases from 0.1 to 0.7. Moreover, the chemical reaction parameter increase enhances the interfacial mass transfer. The volumetric entropy generation shows a sharp maximum at the solid boundary. The outcomes are directly relevant to the design of catalytic chemical reactors, thermal exchangers and biomedical transference technologies needing augmented thermal efficiency.