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甲烷水合物导热系数是甲烷水合物勘探、开采、储运以及其他应用过程中一个十分重要的物理参数.我们采用平衡分子动力学(EMD)方法Green-Kubo理论计算温度203.15～263.15K、压力范围3～100MPa、晶穴占有率为0～1的sI甲烷水合物的导热系数,采用的水分子模型包括TIP4P、TIP4P-Ew、TIP4P-FQ、TIP4P/2005、TIP4P/Ice.研究了主客体分子、外界温压条件等对甲烷水合物导热性能的影响.研究结果显示甲烷水合物的低导热性能由主体分子构建的sI笼型结构决定,而客体分子进入笼型结构后,使得笼型结构导热性能增强,同时进入笼型结构的客体分子越多,甲烷水合物导热性能越强.研究结果还显示在高温区域(T>TDebye/3)内不同温度作用下,所有sI水合物具有相似的导热规律.压力对导热系数有一定影响,尤其是在较高压力条件下,压力越高,导热系数越大.而在不同温度和不同压力作用过程中,密度的改变对导热系数的增大或减小几乎没有影响.
Methane hydrate thermal conductivity is a very important physical parameter in methane hydrate exploration, mining, storage and transportation, and other applications.We use the method of equilibrium molecular dynamics (EMD) Green-Kubo theory to calculate the temperature of 203.15 ~ 263.15K, the pressure range The thermal conductivity of sI methane hydrate with 3 ~ 100MPa and 0 ~ 1 occupancy of the crystal lattice was investigated by using water molecule models including TIP4P, TIP4P-Ew, TIP4P-FQ, TIP4P / 2005 and TIP4P / , External temperature and pressure conditions on the thermal conductivity of methane hydrate.The results show that the low thermal conductivity of methane hydrate is determined by the sI cage structure of the host molecule, and the guest molecules into the cage structure, making the cage structure of the thermal conductivity The more guest molecules entering the cage structure, the stronger the thermal conductivity of methane hydrate.The results also show that all sI hydrates have similar thermal conductivity at different temperatures in the high temperature region (T> TDebye / 3) The pressure on the thermal conductivity has a certain impact, especially in the higher pressure conditions, the higher the pressure, the greater the thermal conductivity.At different temperatures and different pressures in the process, the secret It changes little effect on increasing or decreasing the thermal conductivity.