Investigation on enhanced density ratio recovery and numerical stability in real physical field under multi-component multiphase LBM

Pseudopotential models, a type of lattice Boltzmann method, find wide application in phenomena like boiling and solid-liquid phase transitions. Extending the previous independent surface tension calculation to the nonorthogonal multiple relaxation time model aims to decouple the density ratio and surface tension. While prior studies focused on high-density ratio single-component systems, real-world scenarios often involve multicomponent systems. This paper simplifies the pseudopotential multi-component model based on component interaction principles. This simplification allows for decoupling the parameter adjustments and property reconstruction for water and air components, thereby reducing the iteration deviations coupled in the original model and improving convergence. Additionally, we propose numerical methods for model correction to enhance stability, applicable in cases of extreme density ratios (>10<^>4). Typically, the stability and accuracy of pseudopotential models are affected by spurious velocity near the phase interface and negative densities in local regions. This study observes a direct correlation between density decrease at the phase interface and increased spurious velocity and proposes two correction methods. The first method involves correcting negative density points during particle population movement, termed "Unphysical Distribution Function" (UDC) correction. The second method introduces "Extremely Low-Density Correction" (EDC) to smooth the density decrease at the phase interface.