基于扩散势能和自由体积的扩散系数模型

为探讨流体扩散机理进而研究流体传递性质，在同时考虑自由体积和活化能的基础上，提出一种计算自扩散系数模型，并给出新模型中各个因子的物理含义．还提出一种计算扩散势能的新方法，并应用于新模型．同时将衍生Vander Waals状态方程应用于求解自由体积，式中所需径向分布函数由Morsali—Goharshadi方程得到．结果表明在相同条件下，新模型比原自由体积模型更准确．因此在计算自扩散系数时，需要同时考虑自由体积和活化能．

Diffusion Coefficient Model Based on Potential Energy and Free Volume

In order to explore the diffusion mechanism and study the transport properties of fluids, a new model of self-diffusion coefficients was proposed based on the concepts of molecular free volume and activation energy. The unknown parameters of this model were defined. At the same time a new method to calculate activation energy was devised and applied to the new model for calculating self-diffusion coefficients. In addition, the free volume was defined by implementing the generic Van der Waals equation of state, the radial distribution function of which was obtained by using the Morsali-Goharshadi empirical formula. Under the same conditions, the new model is more accurate than the original free volume one. So both free volume and activation energy should be considered while computing self-diffusion coefficient.