论文标题
异质多孔介质中电流流的涡流
Vortices of Electro-osmotic Flow in Heterogeneous Porous Media
论文作者
论文摘要
多孔培养基中电动传输的传统模型基于均质的材料特性，该特性忽略了微观波动的任何宏观效应。这种观点不仅是为了方便起见，而且是出于与电场成正比的无关电渗透流的预期，以均匀带电的表面（或恒定的Zeta电位）在薄双层的极限下。在这里，我们表明多孔介质的固有异质性通常会导致宏观涡流模式，这对对流的运输和混合具有重要意义。这些涡流流是由于压力驱动和电渗透流之间的竞争，其大小的特征在于渗透率或表面电荷中异质性的相关长度。涡流的出现由单个无量纲控制参数控制，该参数定义为典型的电渗透速度与总平均速度的比率。
Traditional models of electrokinetic transport in porous media are based on homogenized material properties, which neglect any macroscopic effects of microscopic fluctuations. This perspective is taken not only for convenience, but also motivated by the expectation of irrotational electro-osmotic flow, proportional to the electric field, for uniformly charged surfaces (or constant zeta potential) in the limit of thin double layers. Here, we show that the inherent heterogeneity of porous media generally leads to macroscopic vortex patterns, which have important implications for convective transport and mixing. These vortical flows originate due to competition between pressure-driven and electro-osmotic flows, and their size are characterized by the correlation length of heterogeneity in permeability or surface charge. The appearance of vortices is controlled by a single dimensionless control parameter, defined as the ratio of a typical electro-osmotic velocity to the total mean velocity.
