Thermal gradient and elastic dependence of induced charge electro-osmosis in viscoelastic fluids

Abstract

Induced charge electro-osmosis has notable implementation possibilities in thermal management and efficient electrokinetic micropumps. We present the coupled numerical implementation around a polarized cylinder subject to an external electric field with the influence of different polymer elasticity and thermal gradients. The azimuthal velocity, flow types, kinetic energy, elastic energy, ion transport behavior, and heat transfer capability are investigated in detail. The results show that the inflow and outflow rates approximately overlap for a typical small voltage limit ϕ < 0.1. The Rayleigh number (Ra) significantly influences the elastic energy accumulation and evolution time to the final steady state. The thermal buoyancy forces are not sufficient to create typical thermogravitational convection with passive heat transfer when Ra < 1.3 × 10−3, resulting in heat diffusion and electro-osmosis velocity dominating the temperature distribution. The Nusselt number (Nu) plot with a weak viscoelastic effect implies an asymptotic Nu=0.44+2.65Ra0.35 relation. Relevant results open possibilities for enhanced mixing and heat transfer in microdevices, providing insight into barriers to the non-Newtonian nature of electrokinetic dynamics.