Arrhenius Activation Energy on Viscous and Radiative Heating of Hybridized Chemical Reactive Magnetized‐Casson Nanofluid Flow in Saturated Porous Media With Varied Heat Source/Sink

ABSTRACT This study analyzes the influence of Arrhenius activation energy on the chemically reactive, magnetohydrodynamic Casson hybrid nanofluid flow past an exponentially stretching surface embedded in a Darcy–Forchheimer porous medium with a non‐uniform heat source/sink. The governing nonlinear partial differential equations, formulated under the Rosseland approximation for radiative heat flux, were reduced to coupled ordinary differential equations using similarity transformations. These equations were solved numerically via the fourth‐order Runge–Kutta method with a shooting algorithm. Validation against existing benchmark results showed excellent agreement. Furthermore, the streamline patterns for mono, nano, and hybrid nanofluids are presented to analyze flow. Casson fluid properties, stimulated by yield stress, alter the velocity and temperature fields due to internal resistance. The non‐uniform heat sources and porosity variation raise thermal energy input and flow spatial heterogeneity resistance, leading to complex thermal boundary interaction. Arrhenius activation energy does not affect the fluid temperature but meaningfully boosts the chemical reaction rate by enhancing the species concentration gradient. The hybridized nanofluid composition augments thermal conductivity as a result of free nanoparticles' collision, which inspires heat transfer performance. These findings hold significant assurance for practical applications in sustainability and energy efficiency, leading to the development of environmental benefits and reduced energy costs. These findings demonstrate that hybrid nanofluid composition and nonlinear rheological effects can be tuned to optimize heat and mass transfer in bio‐convective systems, catalytic porous reactors, and solar thermal applications.