Electrokinetic flow in a microchannel driven by charged surface heterogeneity in the presence of an external electric field is investigated by three-dimensional simulations. A computational framework is developed coupling a two-relaxation-time lattice Boltzmann solver for the transport equations of fluids, charged species, and passive tracing scalars and a fast Poisson solver for the electric potential. The two-relaxation-time lattice Boltzmann method is used to resolve the spatiotemporal distribution of flow field, ion concentration, and two passive tracing scalars. The fast Poisson solver is used to solve the electric potential at every time step. Three charged surface patterns together with various external electric fields are investigated. The induced electrokinetic vortices contribute to the mixing and transport enhancement of the passive scalars, depending on the surface patterns and the external electric field. The transport enhancement is found to follow a power law with respect to the magnitude of the external electric field.

中文翻译：

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具有带电表面异质性的电动流动增强了微通道中的混合和传输

通过三维模拟研究了在存在外部电场的情况下由带电表面异质性驱动的微通道中的电动势流动。开发了一个计算框架，该框架结合了用于流体，带电物质和无源跟踪标量的输运方程的两弛豫时间晶格玻尔兹曼求解器和用于电势的快速泊松求解器。两次弛豫时间格子Boltzmann方法用于解析流场，离子浓度和两个被动跟踪标量的时空分布。快速泊松求解器用于在每个时间步求解电位。研究了三个带电的表面图案以及各种外部电场。取决于表面图案和外部电场，感应的电动涡流有助于无源标量的混合和传输增强。发现传输增强遵循关于外部电场的大小的幂定律。