THERMAL RADIATION AND HEAT GENERATION EFFECTS ON UNSTEADY MAGNETOHYDRODYNAMIC FREE CONVECTION FLOW PAST AN INFINITE VERTICAL PLATE WITH COUPLED HEAT AND MASS TRANSFER

Abstract

Magnetohydrodynamic (MHD) free convection flow with coupled heat and mass transfer plays a vital role in nuclear cooling, polymer processing, and energy systems. However, the combined influence of thermal radiation and internal heat generation on unsteady Casson fluid flow past a vertical plate remains insufficiently explored. To address this limitation, the present study develops a comprehensive mathematical model incorporating magnetic field effects, buoyancy forces, radiation parameter (), and heat generation parameter (). The governing nonlinear partial differential equations are transformed into nondimensional form and solved numerically using the Crank–Nicolson implicit finite difference method with 101 spatial grid points and 200-time steps. Numerical results reveal that increasing the radiation parameter from  to  enhances the Nusselt number from −0.055 to −0.042 (≈24% improvement in heat transfer rate). Similarly, peak velocity increases from 1.6 to 4.4 as the thermal Grashof number rises from 2 to 10. Higher Schmidt number reduces concentration boundary thickness significantly. Overall, radiation and buoyancy enhance thermal transport, while magnetic effects suppress velocity, providing valuable insights for thermal system optimization.