CO₂ hydrates are ice-like substances in which CO₂ molecules are encapsulated in water and are known to reduce the rate at which CO₂ dissolves in water. It is believed that the thickness of the hydrate film is dominant in the dissolution rate. In this study, we have developed a model that takes into account two factors: the permeation of H₂O molecules and the change in film thickness. First, mass transfer coefficients were measured from dissolution experiments of CO₂ hydrate, and it was found that existing empirical equations could predict the mass transfer coefficients near the hydrate. Next, molecular dynamics simulations were carried out to determine the self-diffusion coefficients between CO_2. In these calculations, intercage hopping and intracage migration of the molecules were identified based on their migration distances. These results indicate that the kinetic model proposed in this study can reproduce the CO₂ hydrate film thickness well.

中文翻译：

---

基于分子动力学的 CO2 水合物层形成与生长模型

CO ₂水合物是冰状物质，其中CO ₂分子被包裹在水中，并且已知会降低CO ₂在水中溶解的速率。据信，水合物膜的厚度在溶解速率中起主导作用。在这项研究中，我们开发了一个模型，该模型考虑了两个因素：H ₂ O 分子的渗透和薄膜厚度的变化。首先，通过CO ₂水合物的溶解实验测量了传质系数，发现现有的经验方程可以预测水合物附近的传质系数。接下来，进行分子动力学模拟以确定 CO 之间的自扩散系数_2.在这些计算中，分子的笼间跳跃和笼内迁移是根据它们的迁移距离确定的。这些结果表明，本研究提出的动力学模型可以很好地再现CO ₂水合物膜厚。