Irreversibility Analysis and Magnetohydrodynamic Bioconvection of Motile Microorganisms in Eyring-Powell Nanofluids With Joule Heating and Arrhenius Kinetics

MHD Bioconvective Eyring-Powell Nanofluids

Abstract

The present study brings forward a detailed numerical study that examines entropy-optimized bioconvective transport in chemically reacting Eyring-Powell nanofluids moving over stretching surfaces, which is considered in a Darcy-Forchheimer porous medium. The effects of thermophoresis and Brownian motion is included in the model together with the behavior of moving gyrotactic microorganisms through its implementation of nonlinear mixed convection, Arrhenius activation energy, and magnetohydrodynamic effects within the Buongiorno framework. A high-order collocation procedure is used for the numerical solution of the governing equations. The results demonstrate that thermal and concentration Grashof numbers create an increase in fluid velocity because they produce stronger buoyancy effects. The combination of the magnetic parameter with the Eyring rheological parameters leads to reduced flow momentum because of resistance from Lorentz forces. Internal heat generation and Joule heating enhance thermal transport, while increased thermophoresis and Brownian motion reduce the local Nusselt number. Microorganism density shows high sensitivity to Péclet and bioconvection Lewis numbers, with higher values thinning the bioconvection layer. Entropy analysis reveals that irreversibility reaches its highest level near the surface, primarily due to the combined effects of fluid friction, porous medium resistance, and magnetic field–induced energy dissipation. These insights contribute to a better understanding of the underlying transport mechanisms and may support the design and optimization of bio-thermal systems, including microbial fuel cells and advanced cooling technologies.

Bangladesh Journal of Physics, Vol. 33, Issue 1, pp. 25 – 49, June 2026