缔合型链式硬球自扩散系数方程

Associating Hard Sphere Chain Equation for Self-diffusion Coefficient

将链式硬球模型自扩散系数方程与统计缔合流体理论(SAFT)相结合起来。实际非球状的缔合分子以有缔合点的硬球链来模拟。缔合流体中自扩散系数被认为是由非缔合贡献和氢键缔合贡献两部分组成: 链式硬球自扩散系数方程用以计算非缔合流体的自扩散系数,而统计缔合流体理论描述了氢键数与密度和温度的关系,从而得到缔合对自扩散系数的影响。对于水(包括超临界水)、醇类和HF等流体在宽广的压力和温度范围内, 使用实验数据对本方程进行检验,其自扩散系数的相对平均偏差在7.5%左右。

The new associating hard sphere chain equation combined the hard sphere chain model (HSC) of self-diffusion coefficient with the statistical associating fluid theory (SAFT). The real non-spherical associating molecules were modeled as chains of tangent hard sphere segments with association sites. An equation for the self-diffusion coefficient in a polyatomic associating fluid was presented as a product of a non-hydrogen-bond contribution and a hydrogen-bond contribution. The HSC equation was used to calculated the self-diffusion coefficient for a non-associating fluid and the SAFT equation provides the relation of the density and temperature with the average number of hydrogen bonds in a molecule. The equation reproduces the experimental self-diffusion coefficient with average relative error of about 7.5% for water (including the super-critical water), alcohols and hydrogen fluoride over wide ranges of temperature and pressure.