Heat and mass transfer analysis in magneto-electroosmotic Oldroyd 8-constant fluid flow through a serpentine passage: a comparative FDM-CSCM analysis under convective and soret effects

Abstract

In this draft, an analysis is carried out for Hall currents and variable transport characteristics in an electro-osmotically driven flow inside a serpentine wavy channel. The Oldroyd 8-constant model, along with heat and mass transfer, is taken into account. Assuming a low zeta potential, the Poisson-Boltzmann equation are used to simulate the electric double layer (EDL), and it is linearized using the Debye-Hückel approximation. The flow structure is altered by the Lorentz body force introduced by the interplay between electroosmotic forces and magnetohydrodynamics (MHD). The dimensionless governing equations for momentum, heat, and species concentration are solved numerically using a finite difference method (FDM), with results rigorously validated against an independent Chebyshev spectral collocation method (CSCM). A comprehensive parametric study is conducted to assess the influence of the Helmholtz–Smoluchowski velocity, Hartmann number, Hall parameter, viscoelastic time constants, and thermo-solutal parameters, including the Brinkman, Biot, Schmidt, and Soret numbers. Our results show that near-wall flow acceleration is greatly enhanced by raising the Helmholtz–Smoluchowski velocity, but Hall currents efficiently counteract the resistive Lorentz force exerted by the magnetic field.