On the effects of heat absorption and chemical reaction in MHD flow of upper-convected Maxwell nanofluid over a bidirectional stretching surface with gyrotactic microorganisms: A comparative study

This study investigates the three-dimensional magnetohydrodynamic (MHD) flow of an upper-convected Maxwell nanofluid over a bidirectional stretching surface, incorporating motile microorganisms, nonlinear thermal radiation, chemical reaction, and heat absorption. A comparative analysis between non-Newtonian (Maxwell) and Newtonian nanofluids is performed. The governing nonlinear partial differential equations are reduced to ordinary differential equations via similarity transformations and solved numerically using the bvp4c solver in MATLAB. Key findings demonstrate that increasing the magnetic parameter and Deborah number reduces both axial and transverse velocity components. Higher thermal radiation and thermophoresis parameter elevate the temperature profile. An increase in the chemical reaction parameter and Lewis number significantly reduces nanoparticle concentration. The Brownian motion parameter enhances temperature while reducing concentration. The Nusselt number increases with Prandtl number and decreases with thermophoresis, whereas the Sherwood number declines with both parameters. Increasing the Peclet number reduces the motile microorganism density. Compared to Newtonian nanofluids, the non-Newtonian Maxwell nanofluid exhibits higher temperature yet lower heat transfer rate.