Lattice Boltzmann study of two-phase hydrocarbon fluids based on Peng-Robinson free energy model

In this paper, a lattice Boltzmann (LB) model is presented to study the two-phase hydrocarbon fluid systems. Based on the Peng-Robinson (P-R) free energy model, a Cahn-Hilliard type equation is derived to describe the interfacial properties. In the corresponding LB method, the gradient contribution of chemical potential is treated as source term, while the homogeneous part is put in the equilibrium distribution function, which guarantees its scale order in the Chapman-Enskog analysis. In the numerical experiments, the realistic hydrocarbon components of propane are numerically studied by the presented LB model in three dimensions. The numerical results show that the predicted surface tension and capillary pressure are in good agreement with laboratory data.