Abstract: A mathematical model was developed to investigate the effect of transient thermal effect on capillary electroosmotic flow. The model consisted of the Poisson-Boltzmann equation, the Navier-Stokes equation, and the energy equation coupled through temperature. Transient developments of the velocity and temperature profiles were obtained. Since the change in the velocity profile with time was mainly caused by the temperature change, the evolutions of the velocity profiles and temperature profiles always synchronized with each other.The developments of temperature profile, as well as velocity profile due to thermal effects were obtained and discussed under different cooling conditions and different electric field strengths. The present model enabled the determination of a suitable cooling condition at the outer surface of the capillary tube to avoid overheating and provided an adequate migration velocity for given dimensionless numbers, which characterized thermal hydraulic fluid flow due to electrokinetic effects.

摘要： 建立微细圆管内电渗流动的非稳态数学模型，模型通过温度将电渗流的Poisson-Boltzmann方程、动量守恒和能量守恒方程耦合起来.详细讨论了在电渗流的初始阶段，焦耳效应对温度场和速度场演化的影响.同时讨论了不同冷却条件和外部电势场强度条件下，电渗流速度场及温度场变化的特点以及自热的发生过程.研究发现，由于速度场的发展主要受温度主控的电解液黏度影响，因此速度场和温度场是同步发展起来的.通过所得到的结果可以为微细管内的电渗流确定合适的冷却条件，以便同时达到有效抑制样品温度和获得较高流动速度的目的.