中文摘要：

基于自由体积理论和摩擦理论，提出了一个新的用于预测流体自扩散系数的理论模型。基于该理论模型，通过结合文献给出的分子动力学模拟数据，推导出了一个可以用于计算Lennard．Jones流体自扩散系数的半经验方程，与文献给出的分子动力学模拟数据相比，方程的平均相对偏差为3．71％。同时，选取了4种不同分子结构的流体作为计算工质，对其自扩散系数进行了计算，结果显示：与文献给出的实验数据相比，作者提出的方程的平均相对偏差为9．32％。

英文摘要：

Based on the free-volume theory and the friction theory, a new theory model for the prediction of self-diffusion coefficient of fluid was proposed. With the proposed model and the molecular dynamics （MD） simulation data obtained from the literature, a new semi-empirical equation for the calculation of self-diffusion coefficient of Lennard-Jones fluid was derived. The calculated results show that, compared with the MD simulation data, the average absolute deviation of using the new semi-empirical equation for Lennard-Jones fluid is 3.71%. In order to further confirm the accuracy of the new semi-empirical equation, the self-diffusion coefficients of four fluids （krypton, hydrogen, carbon dioxide, cyclohexane） with different molecular structures were calculated by the new semi-empirical equation and other two equations in literatures. The results show that, compared with the experiment data in literatures, the average absolute deviation of the calculating results of using the new semi-empirical equation is 9.32%.