A lattice Boltzmann model for multi-component two-phase gas-liquid flow with realistic fluid properties

Multi-component multi-phase flows are of significant interests in nature and engineering problems of different fields. Modeling the phenomena involved in multi-phase flows is challenging, attributed to the complexity in simulating phase interface dynamics and diffusion processes. Owing to its kinetic nature, lattice Boltzmann (LB) method emerges as an attractive computational approach, in dealing with complicated fluid flow problems and microstructure geometries with effectiveness of parallelized processing. However, some critical drawbacks of basic multi-phase LB models, such as the low density and kinematic viscosity ratios, thermodynamic inconsistency, and dependence of surface tension and density distribution on relaxation times, limit its application in realistic multi-component multi-phase systems. Based on the original pseudopotential model and progresses in single-component multi-phase model, a multi-component LB model was proposed to study the two-phase gas-liquid flow with realistic fluid properties. The importance of improved model is in simultaneously realizing the realistic fluid flow characteristics for multi-component two-phase system, including high density and viscosity ratios, good thermodynamic consistency, independently tunable surface tension and appropriate two-phase boundaries. The proposed LB model is validated with Laplace law and visualization experiment results, and the effects of surface tension, gas flow velocity and wall wettability on dynamic behaviors of fluid flow are investigated.