考虑双电层内离子空间效应的行波交流电渗流计算模型研究

发布时间：2018-04-28 11:05

本文选题：电渗 + 反向流动　；参考：《科技通报》2017年02期

【摘要】：行波交流电渗流是微流体芯片中一种重要的流体驱动方式,但目前其常规理论的预测值仍与实验值有较大差异,甚至有时出现流向相反的情况。本文提出了一种用于估算行波电渗流速随频率和溶液电导率而变化的数学模型(包括反向电渗流)。在该模型中,通过综合考虑双电层内离子的空间立体效应和在双电层溶剂分子电粘阻滞效应,推导了双电层内的有效粘度。另外,模型中引入参数Kc和Kr用于校正双电层的等效电容和电阻,并进行了拟合计算。结果表明,在双电层内的粘度大于溶液粘度的十倍乃至百倍以上,双电层特征系数值在高频段的减小导致电极表面电渗作用的分布改变,从而使流动反向。实验结果与模型计算结果相近,论证了本模型较好的预测效果。
[Abstract]:Traveling wave alternating current is an important fluid driving method in microfluidic chips, but the predicted values of the conventional theory are still different from the experimental values, and even sometimes appear in the opposite direction. In this paper, a mathematical model is proposed to estimate the variation of the traveling wave electroosmosis velocity with the frequency and the solution conductivity (including the reverse. In this model, the effective viscosity in the double layer is derived by taking into account the spatial stereoscopic effect of the ions in the double layer and the electric viscosity block effect in the double layer solvent molecules. In addition, the parameters Kc and Kr are introduced to correct the equivalent capacitance and resistance of the double layer, and the fitting calculation is carried out. The results show that the double layer is in the double layer. The internal viscosity is more than ten times or more than the solution viscosity. The decrease of the value of the double layer characteristics at high frequency leads to the change of the distribution of electroosmotic effect on the electrode surface, which makes the flow reverse. The experimental results are similar to the model calculation results, demonstrating the better prediction effect of the model.

【作者单位】：河海大学机电工程学院;
【基金】：江苏省自然科学基金(批准号:BK20161197) 常州市科技计划(社会发展)项目(批准号:CE20165029) 中央高校基本科研业务费专项资金项目(批准号:2015B04414)资助的课题
【分类号】：O357.3

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