Stability Analysis for Dual Solutions of Casson Tetrahybrid Nanofluid Flow with Homogenous–Heterogenous Reactions in a Porous Curved Surface

This study focuses on enhancing thermal conductivity and improving heat transfer, which are critical for applications in industrial processes, engineering systems, and electronics cooling. The investigation presents a stability analysis of dual solutions for Casson tetra-hybrid nanofluid flow over a porous, curved surface with homogeneous and heterogeneous reactions. By employing a non-Newtonian fluid model coupled with the Tiwari-Das approach, the study examines the effects of various factors including nanoparticle volume fraction, Darcy-Forchheimer drag, non-linear mixed convection, magnetic field, mass suction/injection, slip, and convective boundary conditions on velocity, temperature, and concentration profiles, as well as on skin friction and the Nusselt number. The governing equations are transformed via similarity transformations into a system of ordinary differential equations and solved numerically using the MATLAB bvp4c solver. Results indicate that Forchheimer drag, slip velocity, and Casson parameters have similar effects on the velocity profile, while mixed convection and non-linear convection parameters exert opposite influences. Tetra-hybrid nanofluids exhibit superior heat transfer enhancement compared to tri-hybrid and hybrid nanofluids. Increasing homogeneous and heterogeneous reaction parameters decreases the dual solutions of the concentration profile. The first solution of the skin friction coefficient decreases, whereas the dual solutions of the Nusselt number increase due to the effects of mass suction/injection, local porosity, mixed convection, slip velocity, and Casson parameters. Stability analysis confirms that the first solution is stable, while the second solution is unstable. Grid independence tests and agreement with previous studies validate the accuracy and reliability of the results.