Research Projects

The objective of the proposed project is to mathematically study the EOF modulation of non-Newtonian fluids through a nanochannel under an applied electric field. The flow modulation can be done either by changing the material properties of the channel walls and/or by changing the physicochemical properties of the liquid-filled nanochannel. This study will provide a new perspective to address the unaddressed issues, such as (a) charge-regulated PEL or channel walls, (b) the effect of hydrodynamic slip length, (c) nanochannel filled with polyelectrolyte, (d) Ion partitioning effect, (e) Ion steric effect, (f) various type of non-Newtonian models such as power-law, Herschel-Bulkley, Casson and Bingham model on the modulation of EOF. We aim to develop a generalized framework for electrokinetic effects by considering the most general convective-diffusive-electromigration process. The governing equations for EOF are the Poisson equation for electric potential, Nernst-Planck equations for transport of ionic species, Cauchy momentum equations for non-Newtonian fluids in electrolyte region, and Darcy-Brinkman equations for fluid flow through polyelectrolyte region which may be obtained from the Cauchy momentum equations with an additional frictional force due to the presence of the polymer segments in the nanochannel. The governing system of non-linear equations will be solved numerically in a coupled manner through the finite volume method over a staggered grid arrangement without imposing any restriction on parameters like the applied electric field, Debye length, and surface charge density. The most widely used numerical technique SIMPLE (Semi-Implicit Method for Pressure-Linked Equations) will solve the discretized form of the momentum equations. The higher-order upwind scheme QUICK (Quadratic Upwind Interpolation for Convection Kinematics) will be employed to discretize the convection and electromigration terms in the Nernst-Planck equations, ensuring the stability of the numerical scheme. We may further implement analytical methods to deduce approximate analytical results for electric potential and velocity field under various physically meaningful limits. The outcome of the project will provide insights into how electroosmotic forces interact with the rheological properties of non-Newtonian fluids in confined geometries, using theoretical and computational approaches to develop predictive models.