Optimized ANN-based bio-thermodynamic modeling of unsteady flows with coupled nanoparticle–microbial–activation-energy transport in heterogeneous porous media

Abstract

This study presents a novel bio-thermodynamic framework investigating irreversible entropy production in unsteady magnetohydrodynamic bio-nanofluid flow past a permeable slender cylinder within a heterogeneous porous medium. The primary novelty lies in uniquely unifying gyrotactic bioconvection, Arrhenius activation energy, and spatially varying permeability within an active, adaptive suspension model, rather than treating the fluid as a passive carrier. Key physical effects include nonlinear thermal radiation, Darcy–Brinkman porous dissipation, and biochemically coupled transport where nanoparticle migration and microbial motility interact via thermophoresis and chemotaxis. The coupled governing relations are solved using a fully implicit finite-difference framework enhanced by Blottner’s stabilization technique, alongside an optimized ANN framework to map nonlinear input-output relationships. Results reveal that microbial motility can strategically modulate thermodynamic irreversibility; specifically, when microbial swimming dominates diffusion, total entropy generation drops by up to 22%. Similarly, strengthening nanoparticle buoyancy reduces wall shear stress and heat transfer rates by 15–18%. These findings offer direct applications in optimizing bio-hybrid cooling systems, enhancing targeted drug delivery in porous tissues, and designing intelligent energy systems where biological activity is leveraged to suppress thermodynamic losses.