Abstract Water flow in nanoscale channel is demonstrated to be affected by the robust water-wall interactions, including that the flow significantly deviates from the conventional continuum flow. As suggested in different results of experimental observation and simulation in recent literature, nanopores exhibit higher/lower-than-expected flow capacity. Most existing studies are limited to simple geometry that displays a circular cross-section. However, the flow dynamics of water in noncircular pores significantly deviates from the Hagen–Poiseuille flow equation adopted in circular pores that exhibit different contact angles and dimensions. In this study, molecular interactions between water and the solid inner wall are substituted into the formulations of the Lattice Boltzmann method to simulate the flow dynamics in nanopores that exhibit different cross-sectional shapes and wettability. The results show that, under identical cross-sectional area injection pressure, the circular nanopore exhibits the maximum flow capacity. In terms of a circular cross-sectional shape, the constant density lines are also circular and concentric. For angular cross-sectional shape, the constant density lines do not comply with the cross-sectional shape, and the density varies significantly at the corner. The effects of geometry and density distribution of different contact angles are elucidated. An empirical formula under different geometry and wettability has been established, which is of high significance in modeling water flow in various engineering nano-systems such as shale matrix, membrane, and aquaporins.

中文翻译：

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纳米孔几何形状对承压水流的影响：格子 Boltzmann 模拟视图

摘要 纳米通道中的水流被证明受到强大的水壁相互作用的影响，包括流显着偏离常规连续流。正如最近文献中实验观察和模拟的不同结果所表明的那样，纳米孔表现出高于/低于预期的流动能力。大多数现有研究仅限于显示圆形横截面的简单几何。然而，非圆形孔隙中水的流动动力学显着偏离圆形孔隙中采用的 Hagen-Poiseuille 流动方程，这些方程表现出不同的接触角和尺寸。在这项研究中，水和固体内壁之间的分子相互作用被代入格子玻尔兹曼方法的公式中，以模拟表现出不同横截面形状和润湿性的纳米孔中的流动动力学。结果表明，在相同的横截面积注射压力下，圆形纳米孔表现出最大的流动能力。就圆形横截面形状而言，恒定密度线也是圆形和同心的。对于角截面形状，等密度线不符合截面形状，在拐角处密度变化很大。阐明了不同接触角的几何形状和密度分布的影响。建立了不同几何形状和润湿性下的经验公式，