A Diffuse Interface Lattice Boltzmann Model : Limitations, Capabilities, and Modification

The present study is focused on the capabilities and limitations of Lee-Liu’s diffuse interface lattice Boltzmann model, which is applicable to immiscible two-phase flow displacement processes with high-density ratios in porous media. Benchmark problems such as phase separation, the Laplace’s law at a high density and viscosity ratio for a stationary droplet, equilibrium contact angle for high-density ratio fluids, and poiseuille flow at various flow conditions were conducted to validate the model. The issue of mass-conservation violence was investigated for each case and the effect of mobility parameter ( M c ) on the simulation results is discussed in detail. According to the results, this model suffers from the mass-conservation violence especially in the regions where the fluid is in contact with the solid surface . It becomes evident that the geometry of the solid surface has a remarkable impact on this issue. To improve the issue of mass-conservation disobedience, we proposed a modification to this model and compared the predictions of the modified model with the original one