Electro-osmotic nanofluid flow in a curved microchannel

Abstract

Biological mechanisms offer significant improvement in the efficiency of next generation energy systems. Motivated by new developments in distensible pumping systems, ionic electro-kinetic manipulation and nanoscale liquids (”nanofluids”), in the present study a mathematical model is developed to simulate the entropy generation and electro-osmotic transport of nanofluids in a curved deformable microchannel driven by peristaltic transport. Both thermal and species (nano-particle) buoyancy effects are included and Soret and Dufour cross-diffusion effects. The appropriate conservation equations are normalized with scaled variables and the resulting dimensionless nonlinear boundary value problem is solved in a transformed coordinate system. Simplification of the mathematics is achieved via lubrication approximations and low zeta potential (Debye Hückel linearization). The effects of various parameters, i.e. electro-osmotic velocity, EDL (electrical double layer) thickness and zeta potential ratio on velocity profile and temperature profiles are computed. The effects of Brinkman number (viscous heating parameter) and Joule (electrical field heating) parameter on nano-particle concentration profiles are also simulated. The micro-channel curvature effects on the nanofluid flow characteristics and thermal characteristics are also computed. Furthermore, streamline patterns, temperature contours, nano-particles concentration contours and entropy generation rate contours are plotted for various curvature parameters. Results indicate that the curvature of the channel and electro-osmotic body force influence strongly the sources of entropy generation rate. The study finds applications in bio-inspired electro-osmotic nanofluid pumping in microscale energy applications.