In many engineering applications, understanding gas adsorption and its induced swelling in nanoporous materials is crucial. In this study, we propose a novel coarse-grained molecular dynamics (CGMD) model with gas-gas, solid-solid, and gas-solid interactions explicitly controlled to achieve the coupling between gas transport and solid deformation at the microscale. The CGMD model has the capability to recover solid and gas properties, including density, Young's modulus of the solid, and viscosity of the gas to generate a broad range of swelling ratios relevant to nanostructures by using the innovative bead-spring chain networks. A comparison is made between gas transport through deformable and non-deformable nanochannels of varying sizes (35.4–123.9 nm), which is also compared with the macroscopic Hagen-Poiseuille equation. The proposed model has been further tested in a simplified nanoporous medium composed of four randomly distributed spherical solids. The Kozeny-Carman equation can generally describe the relationship between permeability and porosity, but small deviations are observed in the case of swelling porous media. Our results justify the effect of swelling on reducing gas permeability and provide a new approach to modeling gas transport in swelling porous media at the microscale within the framework of CGMD, with potential applications spanning nanofluidics, energy storage technologies, and environmental nanotechnology.

中文翻译：

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一种在膨胀多孔介质中模拟气体传递的粗粒度方法


在许多工程应用中，了解纳米多孔材料中的气体吸附及其诱导溶胀至关重要。在这项研究中，我们提出了一种新的粗粒分子动力学 （CGMD） 模型，其中气体-气体、固体-固体和气-固体相互作用受到明确控制，以实现微观尺度气体传输和固体变形之间的耦合。CGMD 模型能够恢复固体和气体特性，包括密度、固体的杨氏模量和气体的粘度，以通过使用创新的珠弹簧链网络生成与纳米结构相关的广泛膨胀比。比较了通过不同尺寸 （35.4–123.9 nm） 的可变形和不可变形纳米通道的气体传输，并将其与宏观 Hagen-Poiseuille 方程进行了比较。所提出的模型已在由四个随机分布的球形固体组成的简化纳米多孔介质中进行了进一步测试。Kozeny-Carman 方程通常可以描述磁导率和孔隙率之间的关系，但在膨胀的多孔介质中观察到很小的偏差。我们的结果证明了膨胀对降低气体渗透性的影响，并提供了一种在 CGMD 框架内在微尺度上模拟膨胀多孔介质中气体传输的新方法，潜在应用涵盖纳米流体、储能技术和环境纳米技术。