Thermal analysis of MHD radiative flow of hybrid nanofluids in a porous medium between coaxial cylinders

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This study investigates the magnetohydrodynamic (MHD) behavior of a hybrid nanofluid comprising kerosene oil as the base fluid with graphene oxide (GO) and copper (Cu) nanoparticles , confined between coaxial cylinders in a porous medium. The outer cylinder rotates while the inner one remains stationary, and a uniform radial magnetic field is applied. Coaxial cylinder geometries are widely used in double-pipe heat exchangers , rotating machinery , and tubular reactors. The geometry allows for more refined control of inner and outer wall heating or flow rates, useful in systems where precise thermal gradients are desired. The effects of convective heat transfer , viscous dissipation, and thermal radiation are incorporated. By introducing dimensionless parameters , the governing equations in cylindrical coordinates are transformed into a nonlinear system and solved numerically using a multistep predictor-corrector method via the NDSolve command in Mathematica. The results reveal that increasing the magnetic field strength reduces the fluid velocity, indicating strong magnetic damping effects. The temperature of the hybrid nanofluid increases with higher magnetic field strength and with stronger viscous dissipation effects (Eckert number). Additionally, an increase in nanoparticle volume fraction enhances the wall shear stress , while the Nusselt number , representing the heat transfer rate , rises by an increase in hybrid nanoparticle concentration. The study provides detailed graphical and tabulated analysis, demonstrating how varying physical parameters, such as magnetic field intensity , porosity, radiation parameter, and viscous dissipation effects, significantly influence velocity profiles , temperature distributions , pressure variation, and thermal performance. These findings provides valuable insights into optimizing MHD flow and heat transfer in porous media systems, with applications in advanced cooling systems , heat exchangers , and reactors.