Department of Energy and Mineral Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Key Laboratory of High Efficiency and Clean Mechanical Manufacture, Ministry of Education, School of Mechanical Engineering, Shandong University, Jinan 250061, China.
Phys Rev E. 2023 Jan;107(1-2):015304. doi: 10.1103/PhysRevE.107.015304.
The free-energy model can extend the lattice Boltzmann method to multiphase systems. However, there is a lack of models capable of simulating multicomponent multiphase fluids with partial miscibility. In addition, existing models cannot be generalized to honor thermodynamic information provided by any multicomponent equation of state of choice. In this paper, we introduce a free-energy lattice Boltzmann model where the forcing term is determined by the fugacity of the species, the thermodynamic property that connects species partial pressure to chemical potential calculations. By doing so, we are able to carry out multicomponent multiphase simulations of partially miscible fluids and generalize the methodology for use with any multicomponent equation of state of interest. We test this fugacity-based lattice Boltzmann method for the cases of vapor-liquid equilibrium for two- and three-component mixtures in various temperature and pressure conditions. We demonstrate that the model is able to reliably reproduce phase densities and compositions as predicted by multicomponent thermodynamics and can reproduce different characteristic pressure-composition and temperature-composition envelopes with a high degree of accuracy. We also demonstrate that the model can offer accurate predictions under dynamic conditions.
自由能模型可以将格子玻尔兹曼方法扩展到多相系统。然而，目前缺乏能够模拟部分混溶性多组分多相流体的模型。此外，现有的模型无法推广到尊重任何所选多组分状态方程提供的热力学信息。在本文中，我们引入了一种自由能格子玻尔兹曼模型，其中强迫项由物种逸度决定，逸度将物种分压与化学势计算联系起来。通过这种方式，我们能够对部分混溶性流体进行多组分多相模拟，并将该方法推广到任何感兴趣的多组分状态方程。我们针对不同温度和压力条件下的二元和三元混合物的汽液平衡情况，对基于逸度的格子玻尔兹曼方法进行了测试。我们证明该模型能够可靠地再现多组分热力学预测的相密度和组成，并能够以高精度再现不同的特征压力-组成和温度-组成包络线。我们还证明该模型在动态条件下也能提供准确的预测。
