Thermal analysis for magneto- Carreau based ternary hybrid nanofluids over stretchable surfaces under convective conditions

• Heat generation/absorption effects in the magnetohydrodynamic (MHD) flow of Carreau ternary hybrid nanofluids is studied. • Three types of nanoparticles, namely Fe₃O₄, CuO, and MoS₂, dispersed in a sodium alginate-based fluid with various volume fractions. • Numerical treatment is accomplished by using the bvp4c MATLAB solver. • Nusselt number decreases with increased Weissenberg number and magnetic field strength but increases with enhanced nanoparticle volume fraction. This study investigates the magnetohydrodynamic (MHD) mixed convection flow of a Carreau-based ternary hybrid nanofluid past a nonlinearly stretching surface with convective heating, internal heat generation, and radiative effects in a porous medium. The Carreau rheology accounts for shear-thinning behavior under varying Weissenberg numbers, while magnetic and radiation parameters model electromagnetic damping and thermal diffusion. The governing nonlinear partial differential equations are transformed via similarity variables and solved numerically using the Runge–Kutta–Fehlberg (RKF-45) method with a shooting technique. A comprehensive parametric study shows that increasing the Weissenberg number (We = 0–2) reduces the velocity by up to 16.8% , whereas a higher magnetic parameter (M = 0–2) enhances thermal profiles by 12–15% due to Joule heating. The radiation parameter (Rd = 0–1.2) elevates the wall temperature gradient, increasing the Nusselt number by 10.6% , while the Biot number (Bi = 0.5–1.5) intensifies convective heat transfer by nearly 18%. Conversely, increasing the viscosity index (n = 1.0–1.8) raises skin friction by 11%, confirming the shear-thickening influence of the Carreau model.