加压下混合流体汽液界面张力的分子热力学模型

Molecular thermodynamic models ofinterfacial tension for fluid mixtures at high pressure

建立了两个计算近临界点区域混合流体的汽液界面张力统计力学模型：一是将范德华理论１混合规则引入Ｋｉｒｋｗｏｏｄ－Ｂｕｆ纯流体界面张力模型；另一模型是建立在Ｄａｖｉｓ混合流体汽液界面张力模型。Ｄａｖｉｓ模型对单一纯组分流体可还原为Ｋｉｒｋｗｏｏｄ－Ｂｕｆ模型。对２１个纯组分流体的界面张力进行了关联，得到模型的分子参数，对纯流体平均标准差为１２０μＮ／ｍ，温度范围从常温到临界点，压力范围从常压到临界压力。应用两种模型计算了二氧化碳／丁烷混合体系的界面张力。

Two new statistical thermodynamic models for the interfacial tension of mixture near critical points are established. One is based on KirkwoodBuff theory and VdW1 mixing rule with LennardJones fluid, while the other uses Davis interfacial tension model of fluid mixtures, in which some assumptions are introduced. By using these models, the interfacial tensions of 21 pure fluids are correlated to get molecular parameters. The calculated standard deviations (SD) are 120μN/m. At the same time, interfacial tension of a binary mixture for carbon dioxide/butane is calculated up to critical pressure while the average deviations are 102μN/m and 0.270mN/m respectively for two models. The results are satisfactory for engineering application.