Estimation of Joule heating effect on temperature and pressure distribution in electrokinetic‐driven microchannel flows

Abstract

In this study we present simple analytical models that predict the temperature and pressure variations in electrokinetic-driven microchannel flow under the Joule heating effect. For temperature prediction, a simple model shows that the temperature is related to the Joule heating parameter, autothermal Joule heating parameter, external cooling parameter, Peclet number, and the channel length to channel hydraulic diameter ratio. The simple model overpredicted the thermally developed temperature compared with the full numerical simulation, but in good agreement with the experimental measurements. The factors that affect the external cooling parameters, such as the heat transfer coefficient, channel configuration, and channel material are also examined based on this simple model. Based on the mass conservation, a simple model is developed that predicts the pressure variations, including the temperature effect. An adverse pressure gradient is required to satisfy the mass conservation requirement. The temperature effect on the pressure gradient is via the temperature-dependent fluid viscosity and electroosmotic velocity.

Highly Efficient Circulating Tumor Cell Isolation from Whole Blood and Label-Free Enumeration Using Polymer-Based Microfluidics with an Integrated Conductivity Sensor

“…19 In addition to these three metrics, highly efficient quantification of the number of enriched cells must be provided as well.…”

Micro freef‐low IEF enhanced by active cooling and functionalized gels

“…Because Joule heating increases roughly with the voltage squared, higher applied voltages require much more heat dissipation, perhaps more than what is possible by natural convective cooling to the environment. Models for Joule heating in microfluidic channels [17] have explored the effect of insulating material as well as autothermal (runaway) liquid heating.…”

Joule heating in electrokinetic flow

“…However, these authors admitted that their analytical model applied only to cases with not-too-strong electric field due to the linear assumption made in their derivation. This restriction was recently released in Chein et al's [77] analytical model that predicted in good accuracy the experimentally measured temperatures. Their model, however, failed to predict properly the flow field because a uniform electric field had been assumed throughout the channel.…”