Influence of melting surface and multi-slip boundary conditions on MHD Oldroyd-B nanofluid flow over a stretching sheet in porous media with radiation and dissipative effects

• A viscoelastic Oldroyd-B nanofluid model with melting and multi-slip effects is developed. • Nonlinear radiation, Joule heating, and chemical reactions are incorporated. • Velocity, temperature, and concentration slip effects significantly alter boundary layers. • Melting reduces wall resistance and enhances heat and mass transfer performance. • Results provide insight for nano-engineered thermal systems and biomedical devices. This study investigates the combined effects of melting surface conditions and multi-slip boundary interactions on MHD Oldroyd-B nanofluid flow through a porous medium, capturing wall-fluid interactions relevant to modern microfluidic and biomedical applications. Similarity transformations reduce the governing partial differential equations to a system of coupled nonlinear ordinary differential equations, which are solved numerically using a shooting technique combined with the fourth-order Runge–Kutta method. The results reveal that both melting and slip parameters significantly modulate the thermal and solutal boundary layers. An increase in the melting parameter weakens the thermal gradient at the wall, reducing the Nusselt number, while slip conditions suppress shear stress and enhance near-wall fluid mobility. Additionally, velocity-slip reduces wall drag, temperature-slip retards heat exchange, and concentration-slip diminishes nanoparticle diffusion. These findings are critical for optimizing heat and mass transfer in advanced polymeric drug delivery systems and industrial nanofluid-based processes involving viscoelastic media and porous substrates.