论文标题
从蒸气 - 液体共存区域到超临界流体：范德华流体
From the vapor-liquid coexistence region to the supercritical fluid: the van der Waals fluid
论文作者
论文摘要
在这项工作中，通过使用与平均场理论合并的密度梯度理论研究范德华流体的界面系统。基于Maxwell构造产生的平均场分隔界面，我们为密度梯度理论提出了一个高度准确的密度谱模型，该模型促进了对界面区域各种特性的可靠预测。发现局部固有的Helmholtz自由能在界面处在界面处，并且压力张量的正常和切向成分的最大差异对应于固有的Gibbs自由能的最大值。发现整个相空间被由平均场界面和Widom线组成的单线分为气状和液体样区域。因此，超临界流体的两流体特征是从共存区域遗传的。因此，通过状态的范德华方程，使用蒸气 - 液体平衡问题的解决方案完成了所有温度压力 - 体积平面中共存区域的相图。
In this work the interface system of the van der Waals fluid is investigated by using the density gradient theory incorporated with the mean-field theory. Based on the mean-field dividing interface generated by the Maxwell construction, we propose a highly accurate density profile model for the density gradient theory, which facilitates reliable predictions of various properties for the interface region. It is found that the local intrinsic Helmholtz free energy peaks at the interface and that the maximum difference of the normal and tangential components of the pressure tensor corresponds to the maximum of the intrinsic Gibbs free energy. It is found that the entire phase space is divided into gas-like and liquid-like regions by the single line composed of the mean-field interface and the Widom line. The two-fluid feature of the supercritical fluid is hence inherited from the coexistence region. Phase diagrams extended into the coexistence region in all the temperature-pressure-volume planes are thus completed with the solutions to the vapor-liquid equilibrium problem by the van der Waals equation of state.
