Multiphysics analysis of cilia-induced peristalsis in fractional second-grade biofluids: electro-osmosis, heat transfer, and entropy production

Mathematical modelling of biological fluids is essential for understanding physiologically relevant transport mechanisms in micro-scale biomedical systems. This study examines the peristaltic transport of an ionized non-Newtonian biological fluid, modelled as a fractional second-grade fluid, through a ciliated micro-vessel under electro kinetic effects. The analysis emphasizes the role of the electric double layer formed near the peristaltic wall and its influence on fluid motion. The governing nonlinear equations are simplified using the long-wavelength and low-Reynolds-number approximations together with the Debye-Hückel linearization. Thermal effects are incorporated through a modified bio heat equation accounting for viscous dissipation and heat conduction. Thermodynamic irreversibility is evaluated by quantifying entropy generation due to temperature gradients, viscous effects, and electric field interactions. Exact analytical solutions of the resulting boundary value problem are derived and illustrated using Mathematica. The results reveal that increasing the Helmholtz-Smoluchowski velocity UHs and Debye length parameters m significantly enhances axial velocity due to intensified electroosmotic forces. Parameter polarity strongly influences near-wall and core flow behavior. Additionally, increased cilia length (ε) and electrokinetic width retard core flow while accelerating transport near the walls. These findings provide valuable insights for the modelling-based design and optimization of biomedical microfluidic devices, including artificial cilia systems.