Entropy generation and irreversibility analysis of tangent hyperbolic nanofluid flow with slip and convective boundary effects over a porous stretching surface

Abstract

This study undertakes a detailed examination of steady, two-dimensional boundary layer flow of a tangent hyperbolic nanofluid past a stretching sheet embedded within a porous medium, subjected to the action of a transverse magnetic field. The mathematical formulation accounts for the effects of velocity slip, viscous dissipation, Joule (Ohmic) heating, first-order homogeneous chemical reactions and wall heat transfer governed by Newtonian convective cooling. Furthermore, the thermodynamic irreversibilities resulting from fluid friction, heat transport and magnetic field effects are evaluated by entropy production and Bejan number analyses. While previous studies have examined Newtonian and conventional non-Newtonian nanofluid flows, the combined influence of electromagnetic forces, non-Newtonian rheology, slip mechanisms, reactive transport, convective thermal conditions and thermodynamic irreversibility for tangent hyperbolic nanofluids remains largely unexplored—a gap addressed in this work. The governing partial differential equations are reduced to a system of ordinary differential equations through similarity transformations and solved numerically using both the three-stage Lobatto IIIa collocation scheme (bvp4c in MATLAB) and the shooting method with a classical fourth-order Runge–Kutta algorithm. The findings reveal that higher Eckert number $\left(\mathrm{Ec}\right)$ values lead to a substantial reduction in the Nusselt number by 18.3%–53% due to intensified viscous dissipation, but cause a moderate increase in the Sherwood number by 0.5%–1.5%. From the thermodynamic perspective, entropy generation increases with increasing Eckert number and Joule heating parameter and rises with higher chemical reaction parameter and Biot number as well. These patterns offer helpful recommendations for reducing losses and improving thermal efficiency in procedures including biofluid transport and polymer extrusion.