MHD Heat Transfer Enhancement in TiO2-Fe3O4/Water Hybrid Nanofluid Over a Porous Stretching/Shrinking Surface With Suction/Injection and Heat Source Effects

Abstract

Hybrid nanofluids have gained considerable attention in engineering and industrial applications due to their superior thermal conductivity compared to conventional fluids and single component nanofluids, leading to enhanced heat transfer performance. This study investigates the magnetohydrodynamic (MHD) flow and heat transfer characteristics of a TiO₂-Fe₃O₄/water hybrid nanofluid over a porous stretching/shrinking sheet under the influence of suction and injection. The analysis incorporates important energy dissipation mechanisms, including Joule heating, internal heat generation, and thermal radiation effects. A mathematical formulation based on the governing Navier–Stokes and energy equations is developed and subsequently reduced to a system of nonlinear ordinary differential equations using suitable similarity transformations. The resulting boundary value problem is solved numerically using the shooting method in combination with a fourth-order Adams–Moulton scheme. The results reveal that heat transfer is significantly enhanced with increasing Eckert number and radiation parameter, while stronger suction diminishes thermal transport by thinning the thermal boundary layer and increasing the magnetic parameter suppresses velocity while elevating temperature due to Lorentz and Joule heating effects. Increasing the hybrid nanoparticle volume fraction leads to notable enhancements in both velocity and temperature profiles due to improved momentum and energy diffusion. Furthermore, the skin friction coefficient decreases for stretching surfaces, promoting flow stability, whereas an opposite behavior is observed for shrinking surfaces. The magnitude of skin friction increases with higher TiO₂ volume fraction, consistent with the progressive thinning of the boundary layer.