Buongiorno Model-Based Entropy Analysis of Reiner–Philippoff Nanofluid Flow in Tapered Peristaltic Geometries

This study investigates irreversibility patterns in confined flow systems, focusing on entropy generation during nanofluid transport through irregularly shaped channels. Specifically, it examines an asymmetric tapered channel with peristaltic wall motion where the fluid is modeled as a Reiner–Philippoff nanofluid. Utilizing Buongiorno's nanoscale transport framework, the analysis captures the complex dynamics of nanoparticle distribution mechanisms. The mathematical model incorporates critical physical factors, including variable thermal conductivity and viscosity, magnetic field effects, enhanced wall-slip conditions, and dual-mode particle migration driven by Brownian motion and thermophoresis. The governing equations, simplified under long wavelength and low Reynolds number assumptions, are solved using the optimal homotopy analysis method (OHAM). Key system characteristics such as local pressure distribution, thermal fields, velocity profiles, and nanoparticle concentrations are quantified. The results reveal that diffusion mechanisms substantially enhance thermal transport, while magnetic fields exert competing influences on temperature development. Notably, magnetic field intensity correlates positively with entropy generation rates but inversely with the Bejan number. Through detailed parametric studies supported by rigorous mathematical formulations and graphical illustrations, this work elucidates the interplay among system variables and transport phenomena. These findings advance fundamental understanding of irreversible processes in complex fluid flows and provide valuable insights for optimizing heat transfer in industrial and technological applications involving non-Newtonian nanofluids.