有机蒸气-空气扩散系数的分子动力学模拟

气体扩散系数是一个重要的传质基础数据,基于分子模拟理论,利用分子模拟软件Materials Studio 7.0对部分有机蒸气-空气扩散系数,包括正戊烷、正己烷、正庚烷、正辛烷,进行分子动力学模拟,建立气体分子结构模型,构建晶胞,经弛豫、分子动力学运行后,对平衡体系进行分子动力学运行和分析,得到气体分子的均方位移曲线。输出相关数据并计算扩散系数,然后分析分子量及体系温度对模拟结果的影响情况,同时将扩散系数模拟值与实测值进行对比分析,从而验证了该方法的可行性。

Molecular dynamics simulation of organic vapor-air diffusion coefficients

Gas diffusion coefficient is an important basic data of mass transfer. Based on the molecular simulation theory, molecular simulation software of Materials Studio 7.0 was used to simulate the molecular dynamic processes of some organic vapor-air diffusion, including n-pentane, n-hexane, n-heptane, and n-octane. The gas molecular structure model and unit cell were established, and the molecular dynamics of the balanced cell was analyzed after the relaxation and molecular dynamics of the cell was run, and then the curve of the mean square displacement (MSD) was obtained and the diffusion coefficients were calculated. Moreover, the effects of gas molecular weight and system temperature on the coefficients were discussed. Finally, the calculated coefficients and the measured coefficients were compared the errors were analyzed, and the result shows that the simulation method for the diffusion coefficient is feasible.