Thermal and flow analysis of penta-hybrid nanofluids over a 3D bi-directional stretching surface under MHD, radiative effects and slip conditions

With growing demands for efficient thermal management in advanced engineering systems, the use of multi-component nanofluids has gained significant attention. Among them, penta-hybrid nanofluids represent a promising class due to their enhanced thermal conductivity, stability, and flow tunability. This study explores the three-dimensional flow and heat transfer characteristics of penta and ternary hybrid nanofluids over a bi-directionally stretching surface, subject to velocity slip and convective thermal boundary conditions. The mathematical model accounts for the influence of a magnetic field, internal heat generation, thermal radiation, Joule heating, and viscous dissipation. To simplify the complex system of governing partial differential equations, appropriate similarity transformations are employed to reduce them to a set of coupled ordinary differential equations. These transformed equations are then numerically solved using the built-in MATLAB solver bvp4c. The results revealed penta hybrid nanofluid to be thermally superior to ternary hybrid nanofluid with greater values of the Nusselt numbers and skin friction coefficients in the x and y directions. The x-direction velocity decreased with increasing the magnetic field parameter, x-direction velocity slip parameter, and velocity ratio parameter, and the y-direction velocity increased with x-direction velocity slip parameter and velocity ratio parameter while decreased with magnetic field parameter along with the y-direction velocity slip parameter. The temperature profile increases with increasing magnetic field parameter, heat source, and Eckert number in the x and y directions. At fixed values, using penta hybrid nanofluid instead of ternary hybrid nanofluid reduces the skin friction coefficient in the x and y directions by 7.61% and 8.33%, respectively, and increases the Nusselt number by 7.61%. The results indicate the superior thermal performance along with the flow controlling nature of penta hybrid nanofluid, and it emerges as a prime future candidate for application in energy as well as thermal management.