RSM analysis of MHD hybrid nanofluid flow over a magnetized stretching surface with Cattaneo–Christov heat flux in a porous medium

Efficient heat transfer in hybrid nanofluids is essential for many industrial and biomedical applications. This study investigates magnetohydrodynamic hybrid nanofluid flow over a stretching surface embedded in a porous medium using the Cattaneo-Christov heat flux model, which accounts for finite-speed thermal propagation through thermal relaxation. The analysis incorporates convective heating, thermal radiation, and velocity slip, with water containing titanium dioxide and lead nanoparticles as the working fluid. The governing equations are transformed and solved numerically in Mathematica. Response surface methodology and analysis of variance are employed to evaluate parameter sensitivity and validate the statistical significance of the model. Residual analysis and the adjusted (R^2) confirm excellent predictive accuracy. The results indicate that magnetic fields suppress fluid velocity, whereas mixed convection enhances it. Nanoparticle concentration and flow parameters strongly influence skin friction and heat transfer rates, providing useful guidance for the design and optimization of advanced hybrid nanofluid thermal systems.