Coupled Effects of MHD, Solar Radiation, and Arrhenius Chemical Reaction on Third-Grade Hybrid Nanofluid Mixed Convection Flow through a Porous Medium

Abstract

The increasing need for efficient and sustainable thermal systems has driven the exploration of non-Newtonian models such as third-grade fluids, which capture the nonlinear, memory-dependent behavior of many real-world industrial and biological fluids. This study aims to analyze the thermal and flow behavior of a third-grade fluid under the combined influences of mixed convection (through thermal and concentration Grashof numbers), Arrhenius-type chemical reactions, solar radiation, and a transverse magnetic field, while also considering slip boundary effects and a porous channel structure. The model accounts for buoyancy-driven forces coupled with externally imposed flow, as well as temperature-sensitive reaction rates governed by the Arrhenius relation, making it highly relevant to solar energy systems, catalytic reactors, and advanced heat exchangers. The resulting non-linear partial differential equations (PDEs) describing the flow are reduced to ordinary differential equations (ODEs) using suitable similarity transformations. These ODEs, along with their boundary conditions, are numerically solved via the Galerkin Weighted Residual Method (GWRM) implemented in MATHEMATICA 11.3. The findings show that mixed convection significantly enhances heat and mass transfer, while Arrhenius chemical reactions alter the temperature and concentration fields, influencing flow stability. Moreover, strong magnetic fields and thermal radiation improve energy transport, offering key insights into optimizing third-grade fluid-based thermal systems for solar and industrial applications. Keywords: Third-grade fluids, Hybrid nanofluids, Mixed convection, Solar radiation, Solar Radiation, Magneto-hydrodynamics. Nomenclature and abbreviations list