Ⅰ型甲烷水合物稳定性的分子动力学模拟

The Impact of the Stability of DtructureⅠMethane Hydrate by Molecular Dynamics Simulation

利用计算机模拟研究了CH4笼型水合物中的晶穴占有率对甲烷水合物稳定性的影响。模拟结果表明晶穴在部分被占有的情况下,水合物的笼型结构依然能够保持稳定,水合物的势能和压力与晶穴占有率有关,势能随着晶穴占有率的增大而减小,且表现为负值,压力则表现为正值,并且随着占有率的增大而减小,晶体结构被分解的情况除外,通过模拟结果与实验结果的比较,最后推断出最有可能稳定存在的是晶穴被全部占有时的水合物。

The possible hydration numbers of CH4 clathrate hydrates were investigated by computer simulations. Molecular dynamics simulations were performed for the various cage occupancies at the constant - NVT condition. The simulations results showed that even the partial occupation of the cages the clathrate host lattice remained stable. The system potential energy was negative and decreased as a function of cage occupancies. The pressure was positive and decreased roughly as a function of cage occupancies, except for the case when the host lattice was melting. The CH4 molecules exert on stabilization of the cages through the vander Waals intermolecular interactions. The simulation results were compared with experimental hydration numbers.