Electrohydrodynamics within electrical double layer in a pressure-driven flow in presence of finite temperature gradients

TL;DR

This paper investigates how finite temperature gradients influence electrohydrodynamics and streaming potential in pressure-driven flows within narrow channels, incorporating thermoelectric effects without simplifying assumptions.

Contribution

It introduces a comprehensive model coupling electric potential, ionic distribution, fluid velocity, and temperature, addressing non-isothermal electrohydrodynamics in flow-induced electrokinetics.

Findings

Temperature gradients significantly affect streaming potential.

Thermoelectric effects alter flow behavior.

Coupled model provides detailed insights into non-isothermal electrokinetics.

Abstract

A wide spectrum of electrokinetic studies is modelled as isothermal ones to expedite analysis even when such conditions may be extremely difficult to realize in practice. As a clear and novel departure from this trend, we address the case of flow-induced electrohydrodynamics, commonly referred to as streaming potential, in a situation where finite temperature gradients do indeed exist. By way of analysing a model problem of flow through a narrow parallel plate channel, we show that the temperature gradients have a significant effect on the streaming potential, and, consequently, on the flow itself. We incorporate thermoelectric effects in our model by a full-fledged coupling among the electric potential, the ionic species distribution, the fluid velocity and the local fluid temperature fields without resorting to ad hoc simplifications. We expect this expository study to contribute towards more sophisticated future inquiries into practical micro-/nano-fluidic applications coupling thermal field focusing with electrokinetic effects.