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动电学效应对微通道内流体流动特性影响很大,其对通道内粒子分布特性的影响使得通道近壁面流体流动特性极不稳定。本文采用分子动力学方法模拟了二维矩形微通道内NaCl稀电解质溶液的流动特性,考虑存在于不同粒子间的Lennard-Jones势能、静电力、以及带电离子与水分子间的相互作用,得到了粒子在通道内的分布特征。结果显示在动电学效应主要作用于通道壁面附近,而主流区域影响极小。Na~+离子在无量纲通道高度达到0.08和0.91时其浓度达到最大值,沿远离壁面其浓度逐渐降低,与壁面电性相反的Cl~-离子则在无量纲通道高度达到0.15和0.84附近浓度最高。其结果与基于连续介质解理论的Boltzamnn统计分布一致。水分子的浓度在壁面附近也较通道中心处高。
The electrokinetic effect has a great influence on the fluid flow characteristics in the microchannel, and its influence on the particle distribution in the channel makes the fluid flow near the wall of the channel extremely unstable. In this paper, the molecular dynamics simulation was used to simulate the flow characteristics of dilute electrolyte solutions in two-dimensional rectangular microchannels. Considering the Lennard-Jones potential energy, the electrostatic force and the interaction between charged ions and water molecules, Particle distribution in the channel. The results show that the electrokinetic effect mainly acts on the channel wall, while the influence of the mainstream area is minimal. The concentration of Na ~ + ions reaches the maximum when the dimensionless channel height reaches 0.08 and 0.91, and decreases gradually along the distance away from the wall. The Cl ~ - ion with the opposite conductivity to the wall surface reaches the maximum when the dimensionless channel height reaches 0.15 and 0.84 highest. The results are consistent with the Boltzamnn statistical distribution based on continuum solution theory. The concentration of water molecules is also higher near the wall than near the center of the channel.